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Quantum DAT 24 Drive User's Guide

1. Bits Byte 7 6 5 4 3 2 1 0 0 0 0 0 0 1 0 0 0 1 0 0 0 0 0 0 SILI Fixed 2 MSB Transfer Length 3 Transfer Length 4 Transfer Length LSB 5 vendor unique 0 0 0 0 Flag Link This vendor unique field is reserved and must be set to zero Command Descriptor Block Field Description The following table defines the fields in the CDB Field Name Bytes Bits Description Fixed bit 1 0 If this bit is 1 the size of the blocks is fixed as specified by the MODE SELECT Block Descriptor If it is 0 the transfer length contains the number of bytes in the block Suppress 1 1 The SILI Suppress Incorrect Length Indicator bit is used to Incorrect suppress incorrect length error reporting when reading variable Length length blocks Indicator If the SILI bit is 1 and the Fixed bit is 1 the drive returns a Check Condition with Illegal Request sense key with an additional sense code of Invalid Field in CDB When the SILI bit is 1 and Fixed bit is 0 and the only error encountered by the drive is that the actual block length differs from the requested transfer length then the drive Returns a Check Condition if the actual block length is larger than the requested transfer length and the Block Length field in the Mode Parameter block descriptor is nonzero Does not return a Check Condition if the actual block length is smaller than the requested transfer length or if the actual block is larger than the requested block and the block
2. Following the page header are 0 or more log parameters Each log parameter is a special data structure that contains several description bytes and the parameter value itself Subsequent subsections describe the log parameter fields The following table details the log sense page code field Bits 5 4 3 2 1 0 Page Page Information 0 0 0 0 0 0 0 List of available pages 0 0 0 0 1 0 2 Write error counts 0 0 0 0 1 1 3 Read error counts 1 0 1 1 1 0 2E Tape Alert Flags 1 1 0 0 0 0 30 DDS tape log vendor unique 1 1 0 0 0 1 31 Tape capacity vendor unique 1 1 1 0 0 1 39 Data compression transfer log Commands Log Sense 4Dh Page 59 Using Page Control Bits The Page Control PC bits specify the type of counts that the initiator is requesting For page 0 the PC bits are ignored For other pages the PC bits specify the type of parameter values The following table lists the Page Control bit values Bits 7 6 Type Requested Counts 0 0 0 Threshold values 0 1 1 Accumulated values 1 0 2 Default threshold values 1 1 83 DBefaltacumuatedvaues Threshold Values The type 0 indicates the current threshold values If threshold values are requested the drive returns the maximum count that each parameter code can attain the default or the last threshold values set by the last LOG SELECT command Threshold values for pages 2 and 3 can by changed by the initiator through the LOG SELECT command The drive does not change
3. The Selection and Reselection Phases can be terminated for either of the following reasons e A Selection Reselection time out occurs A Target or Initiator did not respond to a Selection or Reselection Phase within a maximum abort time of 200 Sec e A reset signal occurs on the SCSI bus All sequences are terminated and signals are released by all Targets and Initiators The Initiator can use the ATN signal to notify the DAT drive that an IDENTIFY message from the Initiator is ready To ensure that the Target recognizes the Attention condition before the Command Phase is entered the ATN signal must be low before SEL is asserted and BSY de asserted Select With Attention The host system can select the drive only using Select With Attention The Select With Attention allows the host to send the Identify message to specify that the host supports disconnect The host can also use the Select With Attention to send messages other than the Identify message For example a Bus Device Reset or Abort message can be sent to cause the drive to reset itself without affecting any other device on the SCSI bus The DAT drive responds appropriately to the host messages If the drive receives an illegal message it enters the Message Out Phase and sends the Reject message to the host If any reserved bit bits 5 4 or 3 is set an Identify message is rejected Responses to Identify messages with a non zero LUN are described in the following subse
4. 11 Bits 0 1 Description The Page Code field must be set to 02h to select this page The Page Length field must be set to 14 OEh which indicates that 14 parameter bytes follow the Page Length byte The Maximum Burst Size field specifies the maximum amount of data that the drive can transfer during a Data phase before disconnecting if the initiator granted the disconnect capability This value is in increments of 512 bytes That is a value of one means 512 bytes a value of two means 1024 bytes and so forth A value of zero 0000h indicates that no limit exists on the amount of data transferred per connection In that case the drive does not have to disconnect until all requested data is transferred On read operations the drive disconnects when drive buffer is empty and the Allocation Length has not been satisfied On write operations the drive disconnects when the drive buffer is full and the Transfer Length has not been exhausted The Data Transfer Disconnect Control DTDC field values are as follows 00 Data transfer disconnect control is not used 01 The target does not attempt to disconnect once the data transfer of a command has been started until all data the command is to transfer has been completed 10 Reserved 11 The target does not attempt to disconnect once the data transfer of command has been started until the command is complete Control Mode Page 0Ah The Control Mode page allows the
5. Page 3 The drive SCSI interface consists of eighteen signals Nine are control lines and eighteen are data lines Data lines include the parity signal option These signals are described in the following table Signal Name Description BSY SEL C D 0 MSG REQ ACK ATN RST DB 7 0 DB 8 15 DB PO DB P1 Busy Select Control Data Input Output Message Request Acknowledge Attention Reset Data Bus Data Bus Data Bus Data Bus OR tied signal used to show that the data bus is in use Signal used by an Initiator to select a Target or by a Target to reselect an Initiator SEL is driven by the Initiator during the Selection Phase and driven by the Target during a Reselection Phase Target driven signal used to indicate whether Control or Data information is on the data bus True low indicates Control and false high indicates Data Target driven signal used to control data movement direction on the data bus with respect to an Initiator This signal is also used to distinguish between the Selection and Reselection Phases True low indicates input to the Initiator and false high indicates output from the Initiator Target driven signal used to indicate the presence of a Message Phase on the bus True low indicates Message Phase and false high indicates Data Command or Status Phase Target driven signal used to indicate a request for a REQ ACK data transfer
6. The data in the Element Address Assignment page informs the host of which type of elements and how many elements of each type are supported by the current configuration of the Autoloader as defined in the EXCHANGE MEDIUM COMMAND drive The following table shows the layout of this page Bits Byte 7 6 5 4 3 2 1 0 0 Page Code 1Dh 1 0 0 0 1 0 0 1 0 2 0 0 0 0 0 0 0 0 3 0 0 0 0 0 0 0 0 4 0 0 0 0 0 0 0 0 5 0 0 0 0 0 0 0 1 6 0 0 0 0 0 0 0 0 7 0 0 0 0 0 0 1 0 8 0 0 0 0 0 0 0 0 9 Number of Slots in the Magazine 10 0 0 0 0 0 0 0 0 11 0 0 0 0 0 0 0 0 12 0 0 0 0 0 0 0 0 13 0 0 0 0 0 0 0 0 14 0 0 0 0 0 0 0 0 15 0 0 0 0 0 0 0 1 16 0 0 0 0 0 0 0 0 17 0 0 0 0 0 0 0 1 18 0 0 0 0 0 0 0 0 19 0 0 0 0 0 0 0 0 The MODE SENSE parameter list header is different for LUN 0 and LUN 1 For LUN1 bytes 1 and 2 are always zero Also the MODE SENSE parameter list block descriptor is different for LUN 0 and LUN 1 For LUN 1 bytes 0 5 6 and 7 are always zero Device Capabilities Page Autoloader Only 1Fh The following table shows the layout of this page Bits Byte 7 6 5 4 3 2 1 0 0 Page Code 1Fh 1 0 0 0 1 0 0 1 0 2 0 0 0 0 1 0 1 0 3 0 0 0 0 0 0 0 0 4 0 0 0 0 0 0 0 0 5 0 0 0 0 1 0 0 0 6 0 0 0 0 0 0 0 0 7 0 0 0 0 0 0 1 0 8 0 0 0 0 0 0 0 0 9 0 0 0 0 0 0 0 0 Commands Mode Sense 1 Ah Page 101 Bits Byte 7 6 5 4 3 2 1 0 10 0 0 0 0 0 0 0 0 11 0 0 0 0 0 0 0 0 12 0 0 0 0 0 0 0 0 13 0 0 0 0 1 0 0 0 14 0 0 0 0 0 0 0 0 15
7. 9 Block Number 10 Block Number 11 Block Number 12 Block Number 13 Block Number 14 Block Number 15 Block Number LSB 16 File Number MSB 17 File Number 18 File Number 19 File Number 20 File Number 21 File Number 22 File Number 23 File Number LSB 24 Set Number MSB 0 25 Set Number 0 26 Set Number 0 27 Set Number 0 28 Set Number 0 29 Set Number 0 30 Set Number 0 31 Set Number LSB 0 READ POSITION Data Format Field Descriptions The following table lists the field descriptions Page 122 Field Name BOP bit EOP bit BPU Partition Number Block Number File Number Set Number Reserved Bytes Bits 0 7 0 6 0 3 0 2 4 7 8 15 16 23 24 31 DDS 4 SCSI Interface Manual Rev B Description 0 The current logical position is not at BOT 1 The current logical position is at Beginning of Partition BOT 0 The current logical position is not between early warning and end of tape 1 The current logical position is between early warning and end of tape 0 File Number field is valid 1 File Number field is invalid 0 Block Number field is valid 1 Block Number field is invalid This field is always 0 This field indicates the number of logical blocks including filemarks between beginning of medium and the current logical position This field indicates the number of filemarks between beginning of medium and the current logical positi
8. Description Peripheral Device Type Page Code 00h Reserved Page Length 05h Supported Pages 00h Firmware Designation Page 03h Drive Serial Number Page 80h Controller Firmware Revision Page COh Drive Firmware Revision Page C1h The Firmware Designation Page 03h is defined as follows Byte 0 1 2 3 4 11 12 15 16 31 Description Peripheral Device type Page Code 03h Reserved Page Length 1Ch Reserved REV Level Reserved The Controller Firmware Revision Page COh is defined as follows Byte Co m o 4 5 8 9 18 19 22 Description Peripheral Device Type Page Code COh Reserved Page Length 13h ASCII Length 12h REV Level Build Date format yyyy mm dd OEM Model Number The Drive Firmware Revision Page C1h is defined as follows Byte Qoi co m o Description Peripheral Device Type Page Code C1h Reserved Page Length 04h ASCII Length 03h Drive Firmware Revision Level Page 44 DDS 4 SCSI Interface Manual Rev B INQUIRY Drive Serial Number Data Format Page The following table describes the drive serial number which is sent from the drive to the host as data formatted in a parameter list Bits Byte 7 6 5 4 3 2 1 0 Peripheral Device Type Page code 80h Reserved Page Length 7 Drive Serial Number Drive Serial Number Drive Serial Number Drive Serial Number Drive Serial Number Drive Serial Number o CO N oo
9. Mode Select 15h Page 75 Parameter List Header Field Descriptions The following table defines the fields in the Parameter List Header Field Name Buffered Mode Block Descriptor Length Bytes 2 Bits 6 4 Description This field sets the buffering mode of the drive The default mode is 001 buffered The drive may report good status on write commands as soon as all the data specified in the write command has been transferred to the drive s buffer Mode 000 is unbuffered The drive will not report good status on write commands until the data is actually written on the tape This field indicates the number of bytes of block descriptor information that follow the MODE SELECT header The block descriptor length may be set to 00h which indicates that no block descriptor bytes are included in the parameter list This selection is valid and is not considered an error If the block descriptor length is 08h eight bytes of block descriptor information are specified in the parameter list The mode pages can be sent immediately following the header depending on the specified parameter list length Parameter List Block Descriptor The following table presents the Parameter List block descriptor Bits Byte 7 6 5 4 3 2 1 0 0 Density Code 1 0 0 0 0 0 0 0 0 2 0 0 0 0 0 0 0 0 3 0 0 0 0 0 0 0 0 4 0 0 0 0 0 0 0 0 5 MSB Block Length 6 Block Length 7 Block Length LSB Page 76 DDS 4 SCSI Interface Ma
10. SDA search failed 4 44 BB Internal error tape erase failed 4 44 BC Internal error invalid append AFC 4 44 BD Internal error missed R3CP 4 44 BE Hardware adjustment error 4 44 CO Loader error initialization failed at first reference point 4 44 C1 Loader error initialization failure 4 44 C2 Loader error magazine ejection failed 4 44 C3 Loader error elevator cannot move upward 4 44 C4 Loader error elevator cannot move downward 4 44 C5 Loader error cartridge cannot be moved into drive 4 44 C6 Loader error cartridge cannot be inserted into magazine slot 4 44 C7 Loader error cartridge cannot be extracted from magazine slot 4 44 C8 Loader error cartridge cannot be moved from drive 4 44 C9 Loader error magazine cannot be moved into loader 4 44 CA Loader error magazine platform cannot rotate 4 44 CB Loader error unable to lock door 4 44 CC Loader error internal error A 4 44 CD Loader error internal error B 4 44 DO AIC internal DMA FIFO over under run 4 44 D1 AIC internal DMA offset error 4 44 D2 AIC internal DMA parity error Commands Request Sense 03h Page 139 Byte 2 Sense Byte 12 Byte 13 Definition Key ASC ASCQ Additional sense code 4 44 D3 AIC internal read parity error 4 44 D4 Microprocessor Cache Failure 4 44 D5 EEPROM failure 4 44 EO Loader clamp failure 4 44 E1 Loader cassette arm failure 4 44 E2 Loader error LCP failure 4 44 E3 Loader h
11. The tape cartridge is not data grade Any data you back up to the The drive has not been tape is at risk able to read the MRS Replace the cartridge with a data grade tape stripes You are trying to write to a write protected cartridge Write command is Remove the write protection or use another tape attempted to a write protected tape Cleaning Media The tape in the drive is a cleaning cartridge Cleaning tape If you want to back up or restore insert a data grade tape encountered during backup or restore Unsupported Format You have tried to load a cartridge of a type that is not supported by Attempted loaded of this drive unsupported tape format e g DDS1 or DDS2 tapes The operation has failed because the tape in the drive has snapped Tape snapped cut in the 1 Discard the old tape drive where media can be ejected Recoverable Snapped Tape 10 No Removal You cannot eject the cartridge because the tape drive is in use Manual or s w unload Wait until the operation is complete before ejecting the cartridge attempted when prevent media removal on S 2 Restart the operation with a different tape Commands Log Sense 4Dh Page 67 Unrecoverable The operation has failed because the tape in the drive has snapped Tape snapped cut in the Snapped Tape 1 Do not attempt to extract the tape cartridge drive where media cannot 2 Call the tape drive supplier helpline be ejected 16 Forced Eject C The operation has fa
12. drive to report information exception conditions if reporting of recovered errors is allowed by returning a Check Condition status on the next SCSI command excluding Inquiry and Request Sense after an informational exception condition was detected The sense key shall be set to RECOVERED ERROR and the additional sense code shall indicate the cause of the information exception condition Commands Mode Select 15h Page 87 which is 5DOOh for a Tape Alert event The command that has the Check Condition shall complete without error before any exception condition may be reported and thus does NOT need to be repeated 0x4 Unconditionally generate Recovered Error This method instructs the tape drive to report information exception conditions by returning a Check Condition status on the next SCSI command excluding Inquiry and Request Sense after an informational exception condition was detected The sense key shall be set to RECOVERED ERROR and the additional sense code shall indicate the cause of the information exception condition which is 5DOOh for a Tape Alert event The command that has the Check Condition shall complete without error before any exception condition may be reported and thus does NOT need to be repeated 0x5 Generate No Sense This method instructs the tape drive to report information exception conditions by returning a Check Condition status on the next SCSI command excluding Inquiry and Request Sense after an i
13. the SCSI device does not assert a BSY and its SCSI ID if more than a bus settle delay 1 8 Sec has passed since the Bus Free Phase was last observed 4 After waiting at least an Arbitration delay 2 2 Sec measured after asserting a BSY signal the SCSI device examines the data bus If a higher priority SCSI ID bit is true then the SCSI device loses the Arbitration The SCSI device releases its signals and returns to Step 1 If no higher priority SCSI ID bit is true on the bus then the SCSI drive wins the Arbitration and asserts the SEL signal Any other device that participated in the Arbitration Phase and lost Arbitration releases BSY and its SCSI ID bit within a bus clear delay after SEL becomes true A SCSI device that loses Arbitration returns to Step 1 5 The SCSI device that wins Arbitration waits at least one bus clear delay plus a bus settle delay of 1 200 nSec after asserting the SEL signal and changing the condition of other signals NOTE The single SCSI ID bit on the data bus corresponds to the unique ID code of the SCSI device All other SCSI data bus bits are released by the SCSI device Parity is not valid during the Arbitration Phase During the Arbitration Phase DB P may be undriven or driven true but not false Selection and Reselection Phases The Selection and Reselection Phases provide a method for establishing a link between the Initiator and Target When selected by an Initiator that supports disconnects the Ta
14. 0 0 Page 134 Byte 15 16 17 Bits 7 SKSV 6 C D DDS 4 SCSI Interface Manual Rev B 5 4 3 2 1 0 0 0 BPV Bit Pointer MSB Field Pointer Field Pointer LSB Sense Data Field Descriptions The Sense Data field descriptions are shown in the following table Field Name Valid bit Error Code FM bit EOM bit Incorrect Length Indicator ILI Sense Key Information Additional Sense Length Additional Sense Code Additional Sense Code Qualifier SKSV bit C D bit BPV bit Bit Pointer Bytes 0 Bits 7 Description The Valid Bit indicates that the Information field Bytes 3 to 6 contains a valid residual length If the Valid Bit is 1 Residual Length is the requested length minus the actual length in blocks or bytes For example If Write Transfer Length 1000 blocks Residual Length 896 blocks Blocks transferred to drive 192 Transfer Length Residual Length Data written to tape 1000 896 108 And Blocks transferred to drive Data to tape Data trapped in buffer 192 108 84 70h Indicates current errors 71h Indicates a deferred error Then The FM bit indicates that the current command has read a Filemark or a Setmark if the RSMK bit is set The EOM bit indicates one of the following Early warning has been reached or passed in the forward direction The command could not be completed because BOP was encountered in a space reverse command I
15. 0 1 1 1 1 0 0 0 3rd Pty 3rd Pty ID 0 2 0 0 0 0 0 0 0 0 3 0 0 0 0 0 0 0 0 4 0 0 0 0 0 0 0 0 5 vendor unique 0 0 0 0 Flag Link This vendor unique field is reserved and must be set to zero Note The drive also supports the SCSI 3 10 byte Reserve Unit Command We recommend using the 10 byte Reserve Unit Command since the older 6 byte command can only specify a Device ID in the range of 0 to 7 whereas the drive supports a Device ID in the range of 0 to 15 Commands Reserve Unit 16h 56h Page 147 10 byte version The drive also supports the SCSI 3 10 byte Reserve Unit Command The table below shows the descriptor block for the 10 byte CDB Bits Byte 7 6 5 4 3 2 1 0 0 0 1 0 1 0 1 1 1 1 0 0 0 3rd Pty 0 0 LongID 0 2 0 0 0 0 0 0 0 0 3 Third Party Device ID 4 0 0 0 0 0 0 0 0 5 0 0 0 0 0 0 0 0 6 0 0 0 0 0 0 0 0 7 Parameter List Length MSB 8 Parameter List Length LSB 9 vendor unique 0 0 0 0 Flag Link These fields must be set to zero Command Descriptor Block Field Description The following table defines the fields in the CDB Name Bytes Bits Field 3rd Pty 1 bit 3rd Pty 1 ID 4 1 3 Description The Third Party bit indicates whether or not the reservation is for a third party The Third Party ID specifies an Initiator ID for which the release was intended This field is meaningful only when the 3rd Pty bit is set to 1 The drive does not release a third party reservation if this fie
16. 0 bytes 0 1 kilobytes 1 0 megabytes Medium Format Recognition field must be set to 3 indicating the drive is capable of recognizing both the format and the partitions The Partition Size field indicates the size of the additional partition partition 1 formatted on the tape when formatting a dual partition tape The first physical partition is partition 1 The remainder of the tape is partition O Commands Mode Select 15h Page 85 Tape Alert Mode Page 1C Bits Byte 7 6 5 4 3 2 1 0 0 0 Page Code 1Ch Page Length OAh Perf Reserved DExcpt Test Reserved LogErr Reserved MRIE Interval Timer MSB Interval Timer Interval Timer Interval Timer LSB Report Count Test Flag Number MSB Report Count Test Flag Number OO CON oi ol B OO MM ech e Report Count Test Flag Number Report Count Test Flag Number LSB ch DExcpt Default set to 1 When this bit is set to zero the reporting method indicated by the MRIE field is used When this bit is set to one this indicates that the drive disables all information exception operations ignoring the MRIE field In this mode the software must poll the TapeAlert Log page Thus to enable check condition mode set the bit to zero LogErr Default set to 0 When this bit is set to zero this indicates that the logging of informational exception is vendor specific this setting is reserved in Scorpion 40 When this bit is set to one Scorpion 40 logs inform
17. All other pages return a page header followed by zero or more variable length log parameters Page 0 is valid only for the LOG SENSE command When page 0 is requested the four byte page header is returned followed by the page codes used one byte for each the available page codes are returned in ascending order The following table shows the page 0 data format Byte HEX Code Description 0 00 Header page 0 1 00 Header reserved 2 00 Header page length MSB 3 09 Header page length LSB 4 00 Page 0 5 02 Page 2 6 03 Page 3 7 2E Page 2E 8 30 Page 30 9 31 Page 31 10 39 Page 39 11 3A Page 3A 12 3C Page 3C Page Code Data Format for Pages The parameter data returned consists of a four byte page header followed by zero or more log parameters as shown in the following illustration Page Header First Log Parameter Last Log Parameter A log parameter is made up of e A two byte parameter code followed by e A Parameter Control byte e A Parameter Length byte e One or more parameter bytes Parameter Code Field The following table presents the Parameter Code Field format Page 62 DDS 4 SCSI Interface Manual Rev B Bits Byte 7 6 5 4 3 2 1 0 MSB Parameter Code Parameter Code LSB Parameter Control Parameter Length n 3 Parameter Value z 5 o m 2ajo Parameter Value The Parameter Code field identifies the log parameter being returned to the initiator If the Parameter Pointer field of the
18. BLOCK 0 10h M WRITE FILEMARKS 0 11h M SPACE 0 12h M INQUIRY 0 13h O VERIFY 0 15h M MODE SELECT 0 16h M RESERVE UNIT 0 17h M RELEASE UNIT 0 19h M ERASE 0 1Ah M MODE SENSE 0 1Bh O LOAD UNLOAD 0 1CH O RECEIVE DIAGNOSTIC RESULTS 0 1Dh M SEND DIAGNOSTIC 0 1Eh O PREVENT ALLOW MEDIUM REMOVAL 0 2Bh O LOCATE 1 34h O READ POSITION 1 3Bh O WRITE DATA BUFFER 1 3Ch O READ DATA BUFFER 1 44h M REPORT DENSITY SUPPORT SCSI 3 2 4Ch O LOG SELECT 2 4Dh O LOG SENSE 2 56H O RESERVE UNIT SCSI 3 2 57H O RELEASE UNIT SCSI 3 2 A5H A MOVE MEDIUM 5 A6H A EXCHANGE MEDIUM 5 B8H A READ ELEMENT STATUS 5 M Mandatory Command V Vendor Unique Command O Optional Command A Autoloader Command Only SCSI Interface Description Page 5 ANSI X3 131 199x Conformance Statement SCSI 2 General features e Disconnect reconnect arbitration required in SCSI 2 e Supports LVD and single ended drivers e Fixed and variable block transfer lengths e Hard reset e Synchronous data transfers e Parity implemented switch option e Space blocks filemarks EOD and setmarks e Supports third party reservation e Log Sense and Log Select for managing soft errors reporting e MODE SENSE SELECT page to control and report operation of data compression in sequential access devices e Complies with SCSI 2 Section 16 Medium Changer Devices Interface standards conformance The Small Computer System Interface is described in standards including sev
19. Buffer 2 ID ADRS 3 5 Byte 6 8 Transfer Length Description If MODE 0 only the data buffer is loaded If MODE 2 data is loaded starting at the offset location specified by ADRS If Mode 5 the data is transferred to the controller s flash EEPROM and the firmware is restarted For mode 4 and 5 the total transfer length must be A00000h with a starting offset of zero Multiple mode 4 commands can be issued to transfer the data The last micro code transfer mode must be mode 5 to initiate transfer of the micro code to the Flash memory Transfer lengths of zero are valid on any command Only Buffer ID 0 is valid If MODE 2 4 or 5 then ADRS is the offset where data loading begins Otherwise ADRS should be all zeros The Byte Transfer Length specifies the maximum number of bytes transferred to the drive If MODE O it contains a four byte header thus the data length to be stored in the buffer of the drive is Byte Transfer Length minus 4 If MODE 2 4 or 5 the header is not used A Byte Transfer Length of zero indicates that no data are transferred This condition is not an error It is not an error to request a Byte Transfer Length less than the Available Length reported by the READ DATA BUFFER command If MODE O the initiator should ensure that the Byte Transfer Length is not greater than 4 plus the Available Length that is returned in the header of the READ DATA BUFFER command If the Byte Transfer Length is greater th
20. CON OD oa B S YM oO OC OF OF CO CO Of OF CO OF OF O oO OC OF OF CO CO CO OF CO OF OF O oO CO OF OF CO CO CO OF CO OF OF CO oO OC OF OF CO CO CO OF CO OF OF CO oO CO OF OF CO CO CO OF CO OF OF O oO OF OF OF CO CO CO OF CO OF OF O oO CO OF CO CO CO CO OF CO OF OF O oO OC OF CO CO Of CO OF CO CO OF O sech 1 O Commands Read Element Status B8h Page 117 Storage Element Descriptor The 12 byte storage element descriptor is returned within the CDB request for each cartridge slot in the magazine six The following table shows the storage element descriptor Bits Byte 7 6 5 4 3 2 1 0 0 0 0 0 0 0 0 0 1 Element Address 2 0 0 0 0 1 0 0 Full 3 0 0 0 0 0 0 0 0 4 0 0 0 0 0 0 0 0 5 0 0 0 0 0 0 0 0 6 0 0 0 0 0 0 0 0 7 0 0 0 0 0 0 0 0 8 0 0 0 0 0 0 0 0 9 0 0 0 0 0 0 0 0 10 0 0 0 0 0 0 0 0 11 0 0 0 0 0 0 0 0 A Full bit byte 2 bit 0 with a value of 1 indicates that the element contains a cartridge A Full bit with a value of 0 indicates that the element does not contain a cartridge Data Transfer Element Drive Descriptor The Autoloader has only one data transfer element the drive The following table shows the data transfer element descriptor Bits Byte 7 6 5 4 3 2 1 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 1 2 0 0 0 0 1 0 0 Full 3 0 0 0 0 0 0 0 0 4 0 0 0 0 0 0 0 0 5 0 0 0 0 0 0 0 0 6 0 0 1 0 0 0 0 0 7 SCSI Bus Address 8 0 0 0 0 0 0
21. Completion Status for the SEEK BLOCK command is shown in the following table Code Message Description 00h Good e The drive is ready to perform any appropriate command Status e The drive remains in any previously set mode e The tape is positioned before the requested block 02h Check Extended Sense Byte 02h Condition Code Message Description 02h Not Ready No cartridge is inserted in the drive 03h Media Error Unrecoverable data error encountered 04h Hardware Error Drive hardware failure detected 05h Illegal Request The CDB contains an invalid bit Block count of zero was issued 06h Unit Cartridge was changed prior to accepting Attention this command The drive was reset prior to this command 08h Blank Check EOD was encountered The requested block number is greater than the last block written on tape Page 152 DDS 4 SCSI Interface Manual Rev B SEND DIAGNOSTIC 1Dh The SEND DIAGNOSTIC command requests the drive to perform diagnostic operations on itself The diagnostic tests are part of the drive firmware and are more extensive than the power on self tests Two tests are supported as defined in the CDB with bits 2 0 of byte 2 The self test does not require media and will not change any data on media in the drive The Enhanced Diagnostic read write test checks the drive error rates during reading and requires a cartridge All data on the inserted cartridge is destroyed during this test Users should allow up
22. Description The following table defines the fields in the CDB Field Name Bytes Bits Description PC bits 2 6 7 These Page Control bits select one of four possible types of log information These bit settings are shown in Using Page Control Bits Page 2 0 5 This field indicates the requested page code Code Parameter 5 6 7 0 This two byte field specifies the beginning parameter code to be Pointer returned to the initiator All remaining parameter codes are returned in ascending order This field is invalid of page code 0 If the Parameter Pointer field is nonzero when page 0 is requested a Check Condition is returned The sense data are set to Illegal Request Invalid Field in CDB Allocation 7 8 7 0 The Allocation Length field specifies the maximum amount of Length memory space in bytes that the initiator has reserved for log sense data The drive returns the amount of bytes contained in the requested page or the requested Allocation Length whichever is less If the Allocation Length is greater than the actual page length the transfer is truncated The data for only one log sense page can be transferred with any one CDB Log sense data is organized by pages The parameter data for each page is preceded by a four byte page header The page header specifies the page code returned and the length of that page in bytes If the Parameter Pointer field is used to specify a starting parameter code a page header is still returned
23. ELEMENT STATUS Command Descriptor Block The following table shows the layout of the CDB Bits Byte 7 6 5 4 3 2 1 0 0 1 0 1 1 0 0 0 1 LUN 0 0 Element Type Code 2 0 0 0 0 0 0 0 0 3 Starting Element Address 4 MSB Number of Elements 5 Number of Elements LSB 6 0 0 0 0 0 0 0 0 7 MSB Allocation Length 8 Allocation Length 9 Allocation Length LSB 10 0 0 0 0 0 0 0 0 11 vendor unique 0 0 0 0 Flag Link This vendor unique field is reserved and must be set to zero The starting element address specifies the minimum element address to report Only element addresses greater than or equal to the starting element address are reported If the starting element address is undefined an Illegal Request Check Condition is generated The number of elements specifies the maximum number of element descriptors to be reported by the target for this command If the Allocation Length is not sufficient to transfer all of the requested element descriptors the Autoloader transfers all the descriptors that can be completely transferred This situation is not considered an error Element Status Data The data returned by the READ ELEMENT STATUS command consists of an 8 byte header followed by one or three element status pages Within each status page are the appropriate element descriptors The Element type Code can be 0 1 2 or 4 Commands Read Element Status B8h Page 115 The following example illustrates the data structure returned for
24. ID in the range of 0 to 15 Commands Report Density Support 44h Page 127 10 byte version Bits Byte 7 6 5 4 3 2 1 0 0 0 1 0 1 0 1 1 1 1 0 0 0 3rd Pty 0 0 LongID 0 2 0 0 0 0 0 0 0 0 3 Third Party Device ID 4 0 0 0 0 0 0 0 0 5 0 0 0 0 0 0 0 0 6 0 0 0 0 0 0 0 0 7 Parameter List Length MSB 8 Parameter List Length LSB 9 vendor unique 0 0 0 0 Flag Link These fields must be set to zero Command Descriptor Block Field Description The following table defines the fields in the CDB Field Name Bytes Bits Description 3rd Pty bit 1 4 The Third Party bit indicates when a release is for a third party 3rd Pty ID 1 1 3 The Third Party ID specifies a device ID for which the release was intended This field is meaningful only when the 3rd Pty bit is set to 1 The drive does not release a third party reservation if this field does not identify the device for which the drive is currently reserved Completion Status The Completion Status for the RELEASE UNIT command is shown in the following table Code Message Description 00h Good The drive is ready to perform any appropriate command Status e The drive remains in any previously set mode The drive accepts commands from any Initiator The tape position is not changed 02h Check Extended Sense Byte 02h Condition Code Message Description 04h Hardware Error Drive hardware failure detected 05h Illegal Request The CDB contains an invalid bit 06h U
25. In Out Out In In Out In Out Out In Out Supports only two extended messages Synchronous Data Transfer Request and Wide Data Transfer Request SCSI Interface Description Page 19 The following table lists SCSI messages and their definitions Hex Code 00h 02h 04h 05h 06h 07h 08h 09h 0Ah Message Command Complete Save Data Pointer Disconnect Initiator Detected Error Abort Message Reject No Operation Parity Error Linked Command Complete Definition This message is sent from the drive to inform an Initiator that execution of a command terminated and that valid status was sent to the Initiator After successfully sending this message the drive goes to the Bus Free Phase by releasing BSY NOTE The command may have been executed successfully or unsuccessfully as indicated in the status This message is sent from the drive to direct the Initiator to save a copy of the present active data pointer for the drive This message is sent from the drive to inform an Initiator that the present physical path is going to be broken DAT drive plans to disconnect by releasing BSY and a later reconnect is required to complete the current operation If the Initiator detects the Bus Free Phase other than as the result of a Reset condition without first receiving a Disconnect or Command Complete message the Initiator considers this as a catastrophic error condition The
26. In Phase Transfer Period represents the actual transfer period in nanoseconds divided by 4 The REQ ACK Offset is the maximum number of pulses that can be sent by the DAT drive in advance of the number of ACK pulses received from the host establishing a pacing mechanism If the number of REQ pulses is greater than the number of ACK pulses by the REQ ACK Offset the DAT drive stops sending data until after the leading edge of the next ACK is received The ACK REQ Offset is used to prevent an overflow condition in the host s reception buffer during the Data In Phase The REQ ACK Offset should be set to the size of the host s reception buffer minus one To set up a new synchronous data transfer agreement the host asserts the ATN signal and sends an SDTR message The Transfer Period must be set to one of a set of specific values equal to or greater than OAh and less than the maximum rate of the host s reception buffer The ACK REQ Offset will be set to a nonzero value between 4 and the size of the host s reception buffer minus 1 but it must not exceed 32 If the Transfer Period and the ACK REQ Offset are within the ranges described above the DAT drive goes to the Message In Phase and returns an SDTR message with the same Transfer Period and ACK REQ Offset This return indicates a successful completion of the SDTR message exchange The implied synchronous data transfer agreement remains in effect until e A Bus Device Reset message is rec
27. LOG SELECT command affects all initiators Note The subsequent section discusses the LOG SENSE command The log page codes and the log parameter codes are described in that section Parameter data is made up of one or more page descriptors A page descriptor is made up of a four byte page header and one or more log parameters A log parameter is made up of a four byte parameter header and one or more associated parameter data bytes The parameter header contains a two byte parameter code to identify the parameter a Parameter Control byte and a parameter length byte When a counter reaches its maximum value a log exception Check Condition is generated if the RLEC bit is set in the Mode Select Control Mode page The sense data is set to Recovered Error key 01 Log Counter at Maximum qualifier 5B 02 Bytes 15 17 of the Request Sense data specify the page MSB and LSB of the Parameter Code respectively which caused the Log Exception The counters are defined in a following section The drive uses pages 0 2 3 30 and 31 However the LOG SELECT command can only select pages 2 and 3 The following table lists the LOG SELECT page codes Bits Page Page Information 5 4 3 2 1 2 Write error counts 0 0 0 0 1 3 Read error counts 0 0 0 0 1 1 Pages 30 and 31 are vendor unique and refer to the DDS Tape Log and Tape Capacity respectively Page 0 the list of supported pages is available only to the LOG SENSE command Although the cou
28. Link This vendor unique field is reserved and must be set to zero Page 90 DDS 4 SCSI Interface Manual Rev B Command Descriptor Block Field Description The following table defines the fields in the CDB Field Name Bytes Bits DBD bit 1 3 PC field 2 6 7 Page Code 2 0 5 Allocation 4 Length Description If the Disable Block Descriptors DBD bit is set to 0 the drive always returns the block descriptor in the MODE SENSE data If the DBD bit is set to 1 the drive does not return the block descriptor in the MODE SENSE data NOTE When the DBD is 1 the Block Descriptor Length in the parameter header is set to 0 The Page Control field defines the type of parameter values to be returned Valid values are 76 Unit 00 Report current values 01 Report changeable values 10 Report default values 11 Report saved values Note the default values are always the saved values If parameter type 00 report current values is specified the drive returns its current configuration to the host If parameter type 01 report changeable values is specified any values that may be altered by a subsequent MODE SELECT command are returned Any bit that can be changed is set to 1 otherwise the bits are set to 0 If parameter type 10 report default values is specified the drive returns its default power up or reset configuration The Page Code field lets the initiator select the page or pages to be returned by the
29. Miscompare VERIFY data miscompare Page 162 DDS 4 SCSI Interface Manual Rev B WRITE 0Ah The WRITE command transfers one or more data blocks from the Initiator to the drive If the Transfer Length is zero no data is transferred and the current position of the tape is not changed This condition is not considered an error WRITE Command Descriptor Block The following table shows the layout of the Command Descriptor Block Bits Byte 7 6 5 4 3 2 1 0 0 0 0 0 0 1 0 1 0 1 0 0 0 0 0 0 0 Fixed 2 MSB Transfer Length 3 Transfer Length 4 Transfer Length LSB 5 vendor unique 0 0 0 0 Flag Link This vendor unique field is reserved and must be set to zero Each partition on a tape has an Early Warning Point EWP Approximately 10 megabytes can be written to tape after the EWP before reaching the Virtual End of Partition VEOP This allows most write commands that encounter the EWP to successfully complete and not return a residual of unwritten blocks When the EWP is encountered during a write command the drive attempts to complete the current write command and return a check condition status EOM bit set sense key equal to 0 If VEOP is encountered during a write command the sense key is equal to ODh volume overflow All write commands issued when the tape is between the EWP and VEOP will complete with check condition and a sense key with EOM set If volume overflow is reported the sense will have the valid bit set
30. REQ is asserted and then signals its acceptance of the data by asserting the ACK t4 ACK goes low at the Target and the Target de asserts REQ t5 The REQ signal is false The Initiator de asserts ACK After the ACK signal is high the Target can continue the transfer by repeating the steps from t4 Figure 2 4 Signals Used in Transfer from Target to Initiator REG DEAS SER TED eg E a ASSERTED AG E rt r DEASSERTE ES Transfer from Initiator to Target Transfer from Initiator to Target is described in the following table and illustrated in Figure 2 5 Timing Point Action ty The I O signal is de asserted and the Target asserts REQ to request information to The Initiator drives the data and parity signals to their desired values t3 The Initiator asserts the ACK t4 The Target de asserts REQ signaling its acceptance of data The Initiator then releases the data and parity signals t5 The Initiator de asserts ACK The Target can then continue to transfer by asserting the REQ signal SCSI Interface Description Page 13 Figure 2 5 Signals Used in Transfer from Initiator to Target DEASSERTED ASSERTED ACK DEASSERTED ASSERTED l DATA Synchronous Data Transfer Both the Initiator and Target must send a SYNCHRONOUS DATA TRANSFER REQUEST SDTR message in order to set up synchronous data transfer parameters The drives supports both SDTR WDTR extended multibyte messages The hos
31. SCSI Interface Manual Rev B Move Medium Command The SMC Move Medium command moves a cassette from one address to another by specifying a Source Address and a Destination Address Scorpion 240 requires that one of the addresses be 1 the DTE drive This command cannot be used to move a cassette from one magazine slot directly to another However when a cassette is moved from the DTE it is not required that it be placed back in the slot from which it came the Source Storage Element Address will then indicate the last slot it occupied Exchange Medium Command The SMC Exchange Medium command is used to swap the tape in the DTE for another one The command specifies a Source Address First Destination Address and Second Destination Address Scorpion 240 requires that the Source and Second Destination addresses be storage elements magazine slots and the First Destination Address must be the DTE The command moves the cassette in the DTE to the Second Destination Address and the cassette in the Source Address to the DTE Both of the above commands check that there is a cassette in the source address es and no cassette in the destination address before attempting to execute the command If an address is invalid or an element is inappropriately empty or full the autoloader mechanism will not move Furthermore if one of the above commands is invoked with a cassette in the DTE all buffered data will be written to the tape and the tape
32. The Parameter Length byte is the byte count of the parameter value that follows This length is not adjusted to match any truncation The Parameter Value bytes are the actual data requested according to the PC bits of the CDB Write Error Counts page 2 Page 2 contains the Write Error counts which are tabulations of the possible errors if any encountered during writing to tape The page 2 parameter codes for write errors are listed in the following table Parameter Code Length Name 0002 2 Total rewrites 0003 3 Total errors corrected Commands Log Sense 4Dh Page 63 0004 2 Not applicable always returns 0 0005 8 Total bytes processed written 0006 2 Total uncorrectable errors 8007 2 Rewrites since last read type operation The total rewrite count is incremented each time a frame sequence is rewritten on tape Rewrites are used to recover from media errors detected by the RAW read after write checking feature of the drive The total errors corrected count is the same as the total rewrite count The total bytes written count is incremented by the size of each group in bytes that is successfully written to tape This count includes any fill bytes needed to fill a group before the group is written to tape However this count does NOT include the count of additional bytes written during rewrites Also it is greater than the count of write data bytes transferred to the drive The total bytes written count includes
33. a pending Unit Attention Condition before the DAT drive reports Check Condition Status the DAT drive performs the Inquiry Command and does not clear the Unit Attention Condition SCSI Interface Description Page 25 Buffered Mode If the Request Sense Command is received from an Initiator with a pending Unit Attention Condition before the DAT drive reports Check Condition Status the DAT drive reports unit attention sense key and clears the Unit Attention Condition for that Initiator Buffered Mode allows the most efficient operation of the DAT drive The drive defaults to Buffered mode In this mode the drive signals Command Complete when all requested data for a WRITE command has been transferred from the host to the DAT buffer This mode provides data to maintain operation while the host readies a new WRITE Command If an error occurs in writing data to the tape after the DAT drive signals Command Complete an error status is sent on the next Command issued Immediate Function For Initiators that do not support the disconnect feature the Immediate bit provides a means of releasing the bus while the drive is busy completing a function such as repositioning the tape If a command is sent by the Initiator after a previous Immediate Command was accepted the drive continues the Immediate Function it is currently performing and returns a Busy Status for the new command An immediate bit of zero means that the status is returned to the I
34. available Element Status Page Header Each of the three Autoloader element status pages includes an 8 byte header followed by one or more element descriptors The following table shows the header for an element status page Page 116 DDS 4 SCSI Interface Manual Rev B Bits Byte 7 6 5 4 3 2 1 0 0 Element Type Code 1 0 0 0 0 0 0 0 0 2 MSB Element Descriptor Length 3 LSB Element Descriptor Length 4 0 0 0 0 0 0 0 0 5 MSB Byte Count of Descriptor Available 6 Byte Count of Descriptor Available 7 Byte Count of Descriptor Available LSB 8 Element Descriptor n Element Descriptor The element type code field indicates the element type reported in this field The following table defines the element type codes Code Element Type Number of Descriptors Oth Medium Transport changer 1 02h Storage 6 04h Data Transfer drive 1 The byte count of descriptor data available field indicates the number of bytes of element descriptor data available for elements of this element type meeting the request in the CDB This value is not adjusted to match the allocation length available If the magazine is not mounted both Medium Transport Element Type Page and the Storage Element Type Page are not returned Medium Transport Element Changer Descriptor The Autoloader has only one medium transport element the changer The following table shows the medium transport element descriptor Bits Byte N o 5 A e N ch o OO
35. by Position Functions The Count field is not applicable in space to EOD functions In the space to EOD function the tape is positioned such that a subsequent WRITE command appends data to the last recorded information on the tape This positioning is done at high search speed The space to EOD function is useful in support of user defined directories located at the end of recorded data e f physical EOT is encountered while spacing to end of data Check Condition Status is returned and Extended Sense is set to Medium Error e f unrecoverable data error is encountered Check Condition Status is returned Extended Sense Key is set to Medium Error and Extended Sense Valid bit is set indicating Residual Length is non zero Space and the RSMK Bit A Report Setmark RSMK bit determines whether or not the drive recognizes setmarks during a SPACE operation If the value of the RSMK bit is 1 the drive recognizes and reports setmarks when searching for the target If the value of the bit is 0 the drive ignores setmarks during execution of the SPACE command Assume that the data was written on the tape as shown in the following table Position A B C D E F Similar with the LOCATE command if the RSMK bit is 0 when the SPACE command is issued all the setmarks are logically grouped with its nearest Data Block on its BOT side to form a single logical block The following table shows the logical blocks when the RSMK bit is set to O In the
36. command as a diagnostic function for testing the drive buffer memory and confirming the SCSI bus integrity The tape is not accessed during execution of this command READ DATA BUFFER Command Descriptor Block The following table shows the layout of the CDB Bits Byte 7 6 5 4 3 2 1 0 0 0 1 1 1 1 0 0 0 0 0 0 0 Mode Buffer ID MSB Offset Offset Offset LSB Ol CO Noj Oil Pl N vendor unique MSB Allocation Length Allocation Length Allocation Length LSB 0 0 0 0 Flag Link This vendor unique field is reserved and must be set to zero Command Descriptor Block Field Description The following table defines the fields in the CDB Field Name Bytes Bits MODE 1 0 2 Buffer ID 2 Offset 3 5 Allocation 6 8 Length Description If MODE is O data is read starting at offset 0 If MODE is 3 a maximum of four bytes of READ DATA BUFFER Header information is returned Only Buffer ID 0 is valid If MODE is 2 Offset is the offset where data reading begins If MODE is 0 or 3 Offset must equal 0 The Allocation Length specifies the maximum number of bytes the Initiator allocated for returned data For Mode O it includes a four byte header followed by the drives buffer data bytes returned to the Initiator during the Data In Phase For Mode 2 it is the total number of drive buffer data returned Commands Read Data Buffer 8Ch Page 113 READ DATA BUFFER Header The following table shows
37. encountered Page 164 DDS 4 SCSI Interface Manual Rev B WRITE DATA BUFFER 3Bh The WRITE DATA BUFFER command is used in conjunction with the READ DATA BUFFER command as a diagnostic function for testing the data buffer memory of the drive and confirming the SCSI bus integrity The medium is not accessed during the execution of this command The WRITE DATA BUFFER command can also be used to download the controller firmware if the drive is equipped with flash EEPROM Only firmware supplied by Seagate should be downloaded Once the valid firmware is downloaded to the buffer the flash EEPROM is programmed Then within 30 seconds control is transferred to the new firmware and a power on reset occurs The drive is then ready to accept further commands WRITE DATA BUFFER Command Descriptor Block The following table shows the layout of the Command Descriptor Block Bits Byte 7 6 5 4 3 2 1 0 0 0 0 1 1 1 0 1 1 1 0 0 0 0 0 MODE 2 Buffer ID 3 MSB ADRS 4 ADRS 5 ADRS LSB 6 MSB Byte Transfer Length 7 Byte Transfer Length 8 Byte Transfer Length L SB 9 vendor unique 0 0 0 0 Flag Link This vendor unique field is reserved and must be set to zero ADRS is the buffer offset for Mode 2 and is the buffer address for Modes 4 and 5 Commands Write Data Buffer 3Bh Page 165 Command Descriptor Block Field Descriptions The following table provides descriptions of the CDB fields Field Name Bytes Bits MODE 1 0 2
38. equals the difference between the CDB transfer length and the number of actual blocks read e If the Fixed bit is 0 it equals the CDB transfer length On termination the tape is positioned after the filemark on the EOT side of tape Setmarks If the RSMK bit in the Device Configuration Page parameter of the MODE SELECT command is reset 0 Setmarks are ignored and skipped over If the RSMK bit is set 1 and a setmark is encountered the command terminates with a Check Condition The Filemark bit byte 2 bit 7 and the Valid bit byte O bit 7 of the sense data are set The Residual Length field is then set as follows e If the Fixed bit is 1 it equals the difference between the CDB transfer length and the number of actual blocks read e If the Fixed bit is 0 it equals the CDB transfer length On termination the logical position is after the Setmark Commands Read 08h Page 107 Transfer Length Satisfied If the CDB Transfer Length is satisfied the command completes successfully with a Good Status and the tape is positioned on the EOT side of the last block read End of Tape EOT or End of Partition EOP When the end of tape or end of partition position is encountered the command terminates with a Check Condition and Medium Error 03h sense key The Valid bit byte 0 bit 7 and the EOM bit byte 2 bit 6 are set The Residual Length field is then set as follows e If the Fixed bit is 1 it equals the diffe
39. host issues a READ command with a CDB Transfer Length of 514 indicating 514 bytes of data to be read The drive transfers the first 512 bytes of block N then stops because of an Incorrect Length error The logical position after the error is after byte 512 of block N If the SILI bit is set 1 the drive does not report a Check Condition caused by Incorrect Length error If the SILI bit is reset 0 the drive reports a Check Condition and the residual is set to 2 CDB Transfer Length 514 In the above example if the block size of block N is 514 bytes and a READ command specifies a Transfer Length of 512 bytes the drive transfers the first 512 bytes of block N then skips the last two bytes to position itself at the end of byte 514 of block N The residual is set to 2 Because the actual block length exceeds the CDB Transfer Length the drive unconditionally reports Check Condition In this case the residual is set to 2 Completion Status The Completion Status for the READ command is shown in the following table Code Message Description 00h Good e The drive is ready to perform any appropriate command Status e The drive remains in any previously set mode e The tape is positioned on the EOT side of the last block read 02h Check Extended Sense Byte 02h Condition Code Message Description 02h Not Ready No cartridge is inserted in the drive 03h Media Error Unrecoverable data error encountered 04h Hardware Error Drive hardw
40. information about total and remaining storage capacity for each partition Host software can use this page to determine cassette size and remaining capacity while writing to the tape The Tape Capacity Page parameter codes area given in the following table Parameter Code Length Name 0001h 4 Remaining capacity partition O Kbytes 0002h 4 Remaining capacity partition 1 Kbytes 0003h 4 Maximum capacity partition 0 Kbytes 0004h 4 Maximum capacity partition 1 Kbytes All capacities are estimates as to the maximum available user data capacities The actual capacity may be slightly less because of rewrites All values are in kilobytes Partition 1 is the first partition on a dual partition tape For single partition tapes only partition 0 is used The remaining capacity reflects the current head position Thus a rewind will reset the remaining capacity to the maximum capacity The remaining capacity of the partition that is not current will be the same as its maximum capacity The maximum capacity never changes for a particular formatted cartridge To obtain capacity estimates multiply the values returned by 1 024 Commands Log Sense 4Dh Page 71 Data Compression Transfer Log Page Page 39 Page 39 the Data Compression Transfer Log Page allows you to monitor the performance of data compression The Data Compression Page Parameter Codes are given in the following table Name Code Length Description Number of
41. length in the Mode Parameter block descriptor is 0 Transfer 2 4 This field specifies the number of bytes or blocks to be read When a transfer length is 0 no data is transferred This condition is not considered an error Page 106 DDS 4 SCSI Interface Manual Rev B Description of the READ Command The READ command is complete when one of the following conditions is met These conditions are described in the following paragraphs e End of Data EOD is reached e A filemark FM is read e Transfer length is satisfied e End of Tape EOT or end of partition EOP is reached e Unrecoverable data error occurs e Detection of incorrect block length End of Data If EOD is encountered the command terminates with a Check Condition status and a Sense Key of 08h If the Valid bit byte O bit 7 is set indicating a residual count the Residual length field is determined as follows e If the Fixed bit is 1 it equals the difference between the CDB transfer length and the number of actual blocks read e If the Fixed bit is 0 it equals the CDB transfer length The tape is then positioned to allow an Append Data operation Filemark If a filemark is encountered the command terminates with a Check Condition and the filemark bit byte 2 bit 7 of the sense data is set to 1 If the Valid bit byte O bit 7 is set indicating a residual count the Residual length field is determined as follows e If the Fixed bit is 1 it
42. must be either the source or destination element MOVE MEDIUM Command Descriptor Block The following table shows the layout of the CDB Bits Byte 7 6 5 4 3 2 1 0 0 1 0 0 0 1 0 1 1 LUN 0 0 0 0 0 2 0 0 0 0 0 0 0 0 3 0 0 0 0 0 0 0 0 4 0 0 0 0 0 0 0 0 5 Source Address 6 0 0 0 0 0 0 0 0 7 Destination Address 8 0 0 0 0 0 0 0 0 9 0 0 0 0 0 0 0 0 10 0 0 0 0 0 0 0 0 11 vendor unique 0 0 0 0 Flag Link This vendor unique field is reserved and must be set to zero The source address specifies the location from which the cartridge is taken the destination address specifies the location to which the cartridge is moved If the changer is specified an Illegal Request error is returned The following table shows the addresses of the various elements Source Destination Address Source Destination Element 0 Drive Magazine slot 1 Magazine slot 2 Magazine slot 3 Magazine slot 4 Magazine slot 5 o o 5 o m 2 o Magazine slot 6 If the MOVE MEDIUM command is received and the source element is empty or the destination element if different from the source element is full the Autoloader returns a Check Condition and an Illegal sense key The source and destination address can be the drive element address 1 or a valid cassette storage element If the address specified is not assigned to a specific element or the drive is not the source or destination the Autoloader returns a Check Condition and an Illegal Request
43. null pointer SCSI null thread table pointer SCSI SAPI failed SCSI kernel message failed SCSI unknown BE state SCSI unknown FE state SCSI unknown SCSI interrupt SCSI unknown kernel message type SCSI unknown sender SCSI unknown SCSI message SCSI kernel message timeout SCSI unknown DMA message Timer failed SAPI transfer with zero length Unexpected command complete started Unexpected command complete not started Unexpected FE state Unexpected Self Test mode Page 142 DDS 4 SCSI Interface Manual Rev B Bytes 16 17 Definition vendor unique SKSV codes 54 Unexpected DSM primitive 55 Exhausted all command references 56 Unknown Inquiry page 57 Unknown initiator id 58 Unknown sense type 59 AIC internal DMA FIFO over under run 5A AIC internal DMA offset error 5B AIC internal DMA parity error 5C AIC internal read parity error 5D SCSI offset error 5E Unknown Mode page 5F Eject failed 60 Illegal SCSI bus message sequence 61 Invalid DSM command 62 Command should have return busy status 63 Unexpected Command reference found 65 DSM timeout 66 Unknown Kernel message MESSAGE_PARAMETER_T 67 Micro code download failure 68 Unknown Command Reference Type 69 SCSI waiting for RB data 6A pMainRoutine not found 6B pXferDoneRoutine not found DC pCompDoneRoutine not found 6D pDetect routine not found 6E pCmd lost in the FE head 6F pCmd lost in the BE head 70 pActive Cmd lost 71 Command Reference Pool sc Co
44. sense key Commands Move Medium A5h Page 103 Completion Status The Completion Status for the MOVE MEDIUM command is shown in the following table Code Message Description 00h Good Status e The drive is ready for another command The cartridge has been moved to the specified location If the cartridge was moved to the drive it is positioned at BOT 02h Check Extended Sense Byte 02h Condition Code Message Description 02h Not Ready No magazine present 04h Hardware Error Drive hardware failure detected 05h Illegal Request Source element is empty or destination is full Address specified is not assigned to a specific element The drive is not the source or destination 06h Unit Cartridge was changed prior to Attention accepting this command The drive was reset prior to this command Page 104 DDS 4 SCSI Interface Manual Rev B PREVENT ALLOW MEDIA REMOVAL 1Eh If the Prevent Allow Media Removal command is sent the cartridge cannot be ejected using the Eject button on the front of the drive After a Reset the default state of the drive is in the ALLOW command mode An UNLOAD command ejects the cartridge even aftera PREVENT command PREVENT ALLOW MEDIA REMOVAL Command Descriptor Block The following table shows the layout of the CDB Bits Byte 7 6 5 4 3 2 1 0 0 0 0 0 1 1 1 1 0 i E o o Gs o o o Oo 2 0 0 0 0 0 0 0 0 3 ow o o o 30x dz ODER 4 0 0 0 0 0 0 0 PRVNT 5 vendor u
45. size If the current block size differs from the actual block size of the block being read the drive reports an Incorrect Length error When the Fixed bit is reset 0 the CDB Transfer Length field indicates the number of bytes to be read When the actual block size found on tape differs from the CDB Transfer Length an Incorrect Length error is reported The drive reports the Incorrect Length error based on the Suppress Incorrect Length Indicator SILI bit as follows Page 108 DDS 4 SCSI Interface Manual Rev B e fthe actual block length exceeds the CDB Transfer Length the Incorrect Length error is reported e fthe actual block length is smaller than the CDB Transfer Length and the SILI bit is 1 the drive ignores that is suppresses the Incorrect Length error e If the actual block length is different than the CDB Transfer Length and the SILI bit is O the drive reports the Incorrect Length error The drive reports the Incorrect Length error by returning a Check Condition The Incorrect Length Indicator bit byte 2 bit 5 of the Request Sense data is set 1 indicating the Incorrect Length error The Valid bit byte 0 bit 7 of the Request Sense data is also set 1 indicating that the residual data bytes 3 through 6 is valid The meaning of the residual data depends on the setting of the Fixed bit For reading both fixed and variable length blocks the logical position after encountering an Incorrect Length error in bl
46. usage and error rates This information consists of counts related to particular events that occur Count thresholds can be established which automatically generate log exception conditions The LOG SELECT command is used to preset counts of pages 2 and 3 to a specific value or to reset the counts if the maximum count is reached The log sense data is also reset by a SCSI Bus Reset or a Bus Device Reset with the exception of the page 30 and 31 data That data cannot be reset by the initiator Counts of pages 2 and 3 can be read by the LOG SENSE command before a reset and then restored after the reset by issuing the LOG SELECT command The log select data is transferred to the drive by specifying the log select page or pages to initialize Multiple pages can be affected by a single log select CDB However the LOG SENSE command can only request one page at a time The log select parameter data is transferred to the drive to initialize page data The parameter data is organized using structures called og parameters A log parameter is made up of a parameter header that contains a parameter code that identifies the log parameter to be initialized The drive determines the pages used by reading log sense page 0 Any request to initialize an unused log page causes a Check Condition The request sense data is set to Illegal Request Invalid Field in the CDB The log parameter codes within each log page used by the drive are determined by reading ea
47. 0 REPORT DENSITY SUPPORT Ah 131 REPORT DENSITY SUPPORT Command Descriptor Block 131 Command Descriptor Block Field Description 131 REPORT DENSITY Response Data 131 REPORT DENSITY SUPPORT Header 132 REPORT DENSITY SUPPORT Data block descriptor 132 DENSITY SUPPORT Data Block Descriptor Field Descriptions 132 Completion Status eese ener trementem nnne 133 REQUEST BLOCK ADDRESS 02h sss eene 134 REQUEST BLOCK ADDRESS Command Descriptor Block 134 Command Descriptor Block Field Description 134 REQUEST BLOCK ADDRESS Address Data Format 134 REQUEST BLOCK ADDRESS Address Data Field Description 135 Completion Status ssssssssssssssseseseee eene nennen nnne 135 REQUEST SENSE 03h riii edi er dig cart ue d etd d dee cn 136 REQUEST SENSE Command Descriptor Block 136 Sense Data Format 136 Sense Data Field Descriptions sese 137 Page viii DDS 4 SCSI Interface Manual Rev B Definition of Sense kee 138 Additional Sense Code and Code Qualifier sesssssssss 138 Vendor Specific Code Oualters enee neeee enerne tnetennnnnnennnsne e 143 Completion StatUs nee nto PRA a A eR ets 148 RESERVE UNIT 16h P 149 RESERVE UNIT Command Descriptor Block 149 Command Descriptor Block Field Description 150 Completion Status ue
48. 0 the block descriptor length is set to 8 08h indicating that an eight byte block descriptor is returned Medium Type Reporting Byte 1 of the MODE SENSE header format as previously shown is the Medium Type byte accurate after tape motion completes after the initial tape insertion This field is available for reporting the cartridge type via the SCSI bus Because tape format selection is automatic software applications do not usually need to know the tape format However applications that need information about tape format and cartridge type can use the Medium Type field and the Density Code field The values for the Medium Type byte are as follows 33h DDS3 cartridge MRS 34h DDS4 cartridge MRS 35h DAT 72 cartridge MRS 3Fh Non DDS cartridge cleaning cartridge The Medium Type field is currently defined as RESERVED in the ANSI SCSI 2 standard This field has been used by QIC tape devices the above values avoid conflict with QIC drives Parameter List Block Descriptor The following table presents the block descriptor Bits Byte 7 6 5 4 3 2 1 0 0 Density Code 1 0 0 0 0 0 0 0 0 2 0 0 0 0 0 0 0 0 3 0 0 0 0 0 0 0 0 4 0 0 0 0 0 0 0 0 5 MSB Block Length 6 Block Length 7 Block Length LSB Parameter List Block Descriptor Field Descriptions The following table defines the fields in the block descriptor Field Name Bytes Description Commands Mode Sense 1 Ah Page 93 Density 0 The values for the D
49. 0 0 9 0 0 0 0 0 0 0 0 10 0 0 0 0 0 0 0 0 11 0 0 0 0 0 0 0 0 A Full bit byte 2 bit 0 with a value of 1 indicates that the element contains a cartridge A Full bit with a value of 0 indicates that the element does not contain a cartridge The SCSI bus address field provides the SCSI address binary representation of the DAT drive served by the Autoloader This field is set by the SCSI address dip switch or remote connector on the Autoloader unit Page 118 DDS 4 SCSI Interface Manual Rev B Completion Status The Completion Status for the READ ELEMENT STATUS command is shown in the following table Code Message Description 00h Good e The drive is ready for another command Status e All the status data has been sent 02h Check Extended Sense Byte 02h Condition Code Message Description 04h Hardware Error Drive hardware failure detected 05h Illegal Request The CDB contains an invalid bit or an invalid element address 06h Unit Cartridge was changed prior to accepting Attention this command The drive was reset prior to this command Commands Read Position 34h Page 119 READ POSITION 34h The READ POSITION command reports the block address of the current logical block The current logical block is the first logical block that would be read from the current tape partition if a READ command were issued READ POSITION Command Descriptor Block The following table shows the layout of the CDB B
50. 0 0 0 0 0 0 0 0 16 0 0 0 0 0 0 0 0 17 0 0 0 0 0 0 0 0 18 0 0 0 0 0 0 0 0 19 0 0 0 0 0 0 0 0 The data in the Device Capabilities Page informs the initiator of the following A cartridge can be stored in the data transfer and storage elements A MOVE operates from storage to data transfer elements as well as from data transfer to storage elements An EXCHANGE only operates such that the source and second destination addresses must be storage elements but the first destination address must be the data transfer element Completion Status The Completion Status for the MODE SENSE command is shown in the following table Code Message Description 00h Good Status e The drive is ready to perform any appropriate command The drive remains in any previously set mode MODE SENSE does not set or change any modes The tape position is not changed It remains at the previous position 02h Check Condition Extended Sense Byte 02h Code Message Description 02h Not Ready No cartridge is inserted in the drive 04h Hardware Error Drive hardware failure detected 05h Illegal Request The CDB contains an invalid bit 06h Unit Cartridge was changed prior to accepting Attention this command The drive was reset prior to this command Page 102 DDS 4 SCSI Interface Manual Rev B MOVE MEDIUM Autoloader only A5h The MOVE MEDIUM command requests that the Autoloader move a cartridge form a source element to a destination element The drive
51. 0 0 0 Flag Link ius lt c bi o oj o1 o ro o The following table describes the CDB fields common to all Group 0 1 and 2 commands CDB Field Description SCSI Interface Description Page 17 Group Code This field indicates which of eight possible SCSI command groups is specified Seagate drives support Group 0 Command This field indicates which of 32 possible command codes for a particular group Code code is specified Logical Unit The LUN must be set to zero Vendor Unique When set these bits select vendor unique functions in specified commands Flag bit The Flag bit is used only in conjunction with the Link bit and must be set to zero if the Link bit is zero When the Link bit is set the value of the Flag bit determines the appropriate message to send to the Initiator when a linked command completes successfully A 0 value indicates that the Linked Command Complete message is required A 1 value indicates that the Linked Command Complete with Flag message is required Typically the Flag bit is used to cause an interrupt in the Initiator at the end of or at logical intervals in linked command processing Link bit The Link bit is used to indicate that the Initiator desires automatic linking to the next command on successful completion of the current command When the Link bit is one on successful termination of the command the drive returns an Intermediate Status followed by one of the two Command Compl
52. 0001h 8 The total number of complete entities written to or read entities written from the tape since the last power on or Clear Log Number operation Number of 0002h 8 entities read Number of 0003h 8 The total number of records both compressed and records written uncompressed written to or read from the tape since the last power on or Clear Log operation Number of 0004h 8 records read Kilobytes to data 0005h 8 The total number of kilobytes written to or read from the compression tape since the last power on or Clear Log operation When reading this number may be greater than the number transferred to the host due to read ahead Kilobytes from 0006h 8 data compression Kilobytes to tape 0007h 8 The total number of kilobytes written to or read from the tape since the last power on or Clear Log operation Kilobytes from 0008h 8 tape Logical entity size 0009h 8 The logical size of the last entity written to or read from tape size number of records in entity X record size Physical entity 000Ah 8 The physical size of the last entity written to or read from size the tape size entity header length X uncompressed data length Uncompressed 000Bh 8 The total number of times a non compressed entity has entities been encountered on the tape during a read operation since the last power on or Clear Log operation Drive Configuration Information Page Page 3A Parameter Code Length Name 01 4 Raw switch settinas 02 4 Com
53. 1 False 0 True Information Transfer Phases use one or more REQ ACK handshakes to control the information transfer Each REQ ACK handshake allows the transfer of one byte of information During the information transfer phases BSY remains true and SEL remains false C D I O and MSG control signals are valid for a bus settle delay of 400 nSec before assertion of REQ signal at the first handshake and remain valid until negation of ACK at the end of the last handshake Asynchronous Data Transfer The Target controls the direction of information transfer with the I O signal When I O is asserted low information is transferred from the Target to the Initiator When I O is de asserted high information is transferred from the Initiator to the Target Figure 4 shows the data transfer signals for information transfer from Target to Initiator and Figure 2 5 shows the data transfer signals for information transfer from Initiator to Target Each direction of information transfer is discussed in detail in the following paragraphs Transfer from Target to Initiator The transfer from Target to Initiator is described in the following table and illustrated in Figure 2 4 Timing Point Action ty The I O signal is asserted the Target drives the data DB7 0 and parity signals to their desired values to The Target then asserts the REQ signal Page 12 DDS 4 SCSI Interface Manual Rev B ts The Initiator reads the data and parity signals after
54. 1 1 Page Length OEh 2 DCE DCC 0 0 0 0 0 3 DDE RED 0 0 0 0 4 Compression Algorithm 5 Compression Algorithm 6 Compression Algorithm 7 Compression Algorithm 8 Decompression Algorithm 9 Decompression Algorithm 10 Decompression Algorithm 11 Decompression Algorithm 12 0 0 0 0 0 0 0 0 13 0 0 0 0 0 0 0 0 14 0 0 0 0 0 0 0 0 15 0 0 0 0 0 0 0 0 Page 80 DDS 4 SCSI Interface Manual Rev B DC Control Page Field Descriptions The following table describes the fields in the DC Control page Field Name DCC DCE DDE RED Compression Algorithm Decompressi on Algorithm Bytes Bits 2 6 2 7 3 7 3 5 6 4 7 8 11 Description The DCC Data Compression Capable bit indicates that the drive is capable of data compression This bit is always 1 Note that data control compression may be disabled by the switches on the drive The DCE Data Compression Enable bit controls data compression If the value is 1 the drive compresses data received from the host during a WRITE command before it writes the data to tape in the DDS DC format If the value is 0 the drive does not compress data sent during a WRITE command and the host data is written to tape in the uncompressed DDS format The DDE Data Decompression Enable bit is for control of data decompression however for either value the drive decompresses data that has been compressed on the tape before it sends the data to the host during a READ command The RED
55. 2 0 0 0 0 0 0 0 0 3 Page Length n The Page Code field indicates which page is being sent to the drive The Page Length field indicates the length of log parameters in bytes that follow the page header If the LOG SELECT CDB parameter list length specified is too small to transfer complete log parameters for the specified page an Illegal Request Invalid Field in the CDB is returned The following table shows a typical log parameter format Bits Byte 7 6 5 4 3 2 1 0 MSB Parameter Code Parameter Code LSB DU 1 0 ETC TMC 0 0 Parameter Length n 3 Parameter Value 3 5 o m 2 o Parameter Value The Parameter Code field identifies which log parameter is being sent to the drive The parameter codes used for the page 2 Write Error and page 3 Read Error are listed in subsequent tables All of the bits in byte 2 of the Log Parameter are collectively referred to as the Parameter Control byte The Parameter Control byte specifies counter controls The host specifies the Parameter Control byte to control e Whether or not a counter is enabled e Whether or not a Check Condition is generated when a counter is incremented and if so how the Check Condition is generated Each Log Parameter contains only one control byte This control byte is shared between the threshold and accumulated parameters If a LOG SELECT command is Commands Log Select 4Ch Page 55 issued to specify the control bytes for the threshold paramet
56. 3 3B 02 Tape position error at end of medium 3 3B 08 Reposition error 3 3B BF Tape position error with head clog 3 50 00 Write append error 3 50 01 Write append position error 3 51 00 Erase failure 3 52 00 Cartridge fault 3 52 01 Media end of life 3 53 00 Media load or eject failed 3 53 01 Unload tape failure 3 70 nn Decompression exception short algorithm ID of nn 3 81 AO Media failed calibration 4 Hardware Error 4 15 01 Mechanical positioning error 4 40 81 Diagnostic failed FLASH memory checksum test 4 40 82 Diagnostic failed RAM test 4 40 83 Diagnostic failed memory controller test 4 40 84 Diagnostic failed counter timer test 4 40 85 Diagnostic failed SCSI LSI test 4 40 86 Diagnostic failed ECC processor test 4 40 87 Diagnostic failed tape formatter LSI test 4 40 88 Diagnostic failed compression LSI test 4 40 89 Diagnostic failed EEPROM test 4 40 AO Diagnostic initialization failed 4 40 Al Diagnostic SBIST failed 4 40 A2 Diagnostic BBIST failed 4 40 A3 Diagnostic DBIST failed 4 40 A4 Diagnostic DMA setup failed 4 40 A5 Diagnostic host interface RAM failed 4 40 A6 Diagnostic AIC RAM failed 4 40 A7 Diagnostic DMA write interrupt failed 4 40 A8 Diagnostic DMA write FIFO overrun 4 40 A9 Diagnostic DMA write offset error 4 40 AA Diagnostic DMA write host interface parity error 4 40 AB Diagnostic DMA write RD parity error 4 40 AC Diagnostic DMA write micro port access error 4 40 AD Diagnostic DMA write counter
57. 4 00 Logical unit is not ready cause not reportable 2 04 01 Logical unit is in process of becoming ready 2 04 03 Logical unit not ready manual intervention required 2 30 00 Incompatible medium installed 2 30 03 Cleaning cartridge installed 2 30 04 Cannot write medium unknown format 2 3A 00 Medium not present 2 3E 00 Logical unit has not self configured yet 2 3E 02 Timeout on logical unit 2 4C 00 Logical unit has not self configured yet 2 53 00 Media load or eject failed 2 5A 01 Eject button pushed 3 Medium Error 3 00 02 End of partition medium detected 3 03 02 Excessive write errors 3 03 BE Write failure with clogged head 3 0c 00 Write error 3 11 00 Unrecovered read error 3 30 00 Incompatible medium installed 3 30 01 Cannot read medium unknown format 3 30 02 Cannot read medium incompatible format 3 30 07 Cleaning failure 3 30 80 Firmware tape update failed 3 30 84 Entity header wrong length 3 30 85 Reserve byte not in entity header 3 30 86 Bad algorithm byte in entity header 3 30 87 Invalid entity record length field 3 30 88 Invalid entity record count field 3 30 C3 Compressed data format corruption Commands Request Sense 03h Page 137 Byte 2 Sense Byte 12 Byte 13 Definition Key ASC ASCQ Additional sense code 3 30 C4 Block Access Table corruption during reading 3 31 00 Medium format corrupted 3 3B 00 Sequential positioning error 3 3B 01 Tape position error at beginning of medium
58. 5 Message Phase ree e t ide cae s fe doe et ec tee e in Matis 15 Messagen Phase bete eH beate ire am teda 15 Page iv Commands DDS 4 SCSI Interface Manual Rev B Message Out Phase esee entes en tenerse 15 Command Descriptor Block 16 Logical Unit SuppOMt EE 17 SCSI Message Descriptions and Detinitons seen 18 SCSI Status Code Descriptions and Definitions esssssssssss 23 Attention Condltlori atte etu cete ei eee 24 Reset Condition EE ESE AT estne nnne enses E ns entree neis 24 Unit Attention Condition sess nnne nnns 24 Buffered Mode uet tb ten etd Ga ee tab eH dee 25 Immediate EI EE 25 Residual Length Funchon asoson erideiten E i EA T 25 Disconnect Reconnect Funchonm areetan 26 SCSI Memory Address Poimters 27 Current Data Pointers AA 27 Saved Data Pointers Zeg iion edo eh Eee 27 Early Warning F nctlon etiem iiie t it a nade etsi eee ate EENEG 27 Error Heporthg e ERE OU b AGED IER DE D E 28 SOft EITOIS oreet t C Wee tlt e pee dte Hei oe o t He miedos 28 Flair iio 28 Variable and Fixed Mode Recording eese enne 28 Autoloader Operation esssssssssssssssesee enne tnnnen nennen snnt entren 29 General SCSI Information nnne 29 SCSI Medium Changer Commande sse 29 General Operation sesssssssssssessseeeeee enne nnne nnne enne nnne nens 31 Eoading and InrtializatiQni noo cct Pere tine AR RE ether ehe 31 Front Panel Oper
59. 8h Blank Check EOD was encountered while executing a SPACE forward Page 158 DDS 4 SCSI Interface Manual Rev B TEST UNIT READY 00h The TEST UNIT READY command tests for three conditions e The drive is powered on e Acartridge is inserted in the drive e The drive is ready to accept a medium access command If these three conditions are met the drive returns Good Status This command does not access the medium or initiate a diagnostic routine Note For autoloaders the Test Unit Ready command will be accepted by LUN 1 and will test the readiness of the autoloader to accept media movement commands TEST UNIT READY Command Descriptor Block The following table shows the layout of the Command Descriptor Block Bits Byte 7 6 5 4 3 2 1 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 2 0 0 0 0 0 0 0 0 3 0 0 0 0 0 0 0 0 4 0 0 0 0 0 0 0 0 5 vendor unique 0 0 0 0 Flag Link This vendor unique field is reserved and must be set to zero TEST UNIT READY Detailed Operation The following text lists the sense keys plus the additional sense codes and qualifiers reported by the drive during various stages of loading and unloading cartridges The format of the values is additional sense code additional sense qualifier In all other cases CHECK 02 is returned In the following table and text NOT READY indicates a sense key of 02 and UNIT ATTN indicates a sense key of 06 Response while Action First TUR response Ejec
60. Bits Byte 7 6 5 4 3 2 1 0 0 0 0 0 1 0 1 1 1 0 0 0 0 BT CP IMMED 2 0 0 0 0 0 0 0 3 MSB Block Address 4 Block Address 5 Block Address 6 Block Address LSB 7 0 0 0 0 0 0 0 0 8 Partition 9 vendor unique 0 0 0 0 Flag Link This vendor unique field is reserved and must be set to zero Command Descriptor Block Field Description The following table defines the fields in the CDB Field Name Bytes CP bit 1 IMMED 1 bit BT bit 1 Block 3 6 Address Partition 8 Bits 1 Description If the Change Partition bit is 1 the drive changes to the partition whose partition number is specified in the Partition field If this bit is 0 the Partition field is ignored If the IMMED bit is 1 status is returned as soon as the operation is initiated If the IMMED bit is 0 status is not returned until the tape is positioned If the Block Address Type bit is 1 the Block Address field is the total number of logical blocks from the beginning of partition All filemarks and setmarks are ignored when searching the tape If this bit is 0 the Block Address field is the total number of logical blocks filemarks and setmarks from the beginning of partition Filemarks and setmarks are counted when searching the tape These fields specify the logical block address of the block to which the tape is to be positioned Block 0 is the first block in a partition This field is valid only when the CP bit is 1 In that case the field specifi
61. CDB is zero the parameter code of the first log parameter indicates the first parameter code supported by the drive for this log page Parameter codes are always returned in ascending order All of the bits in byte 2 of the log parameter are collectively referred to as the Parameter Control byte The bit descriptions as they are returned by the LOG SENSE command are given in the following table Bit Name Bytes Bits Description Disable Update DU 2 7 When set 1 this bit indicates that the particular parameter is not to be updated by the drive This bit is Set by the drive when the accumulated value reaches its maximum It is also returned set if the host set the bit for the last LOG SELECT command The default is zero For parameter types other than threshold and accumulated values this bit is always 0 Disable Save DS 2 6 A DS bit of zero indicates that the target supports saving for the specified log parameter A DS bit of one indicates that the target does not support saving for the specified log parameter in response to Log Select command Target Save Disable 2 5 Always 0 TSD Enable Threshold 2 4 This bit is returned as set by the last LOG SELECT Comparison ETC command The default is zero Threshold Met Criteria 2 3 2 This field is returned as set by the last LOG SELECT Field TMC command As the default both bits of this field are returned set List Binary Information 2 1 Always 0 List Parameter LP 2 0 Always 0
62. Commands Mode Select 15h Page 77 The following table explains the page layout fields Field Name Bytes Description Page Code 0 The Page Code field identifies the format and parameters for this page as follows Hex Code Page Name 02 Disconnect reconnect 0A Control mode OF Data compression control 10 Device configuration 11 Medium partition 1C Tape Alert Mode 1D Element address assignment Autoloader only 1F Device capabilities Autoloader only Page Length 1 The Page Length field specifies the length in bytes of the mode parameters that follow the Page Length field Mode 2 n The mode parameters are described in the following subsections Parameters Disconnect Reconnect Page 02h The Disconnect Reconnect page allows the host to tune performance of the SCSI bus The following table illustrates this page Bits Byte 7 6 5 4 3 2 1 0 0 0 0 Page Code 02h 1 Page Length OEh 2 0 0 0 0 0 0 0 0 3 0 0 0 0 0 0 0 0 4 0 0 0 0 0 0 0 0 5 0 0 0 0 0 0 0 0 6 0 0 0 0 0 0 0 0 7 0 0 0 0 0 0 0 0 8 0 0 0 0 0 0 0 0 9 0 0 0 0 0 0 0 0 10 MSB Maximum Burst Size 11 Maximum Burst Size LSB 12 0 0 0 0 0 0 DTDC 13 0 0 0 0 0 0 0 0 14 0 0 0 0 0 0 0 0 15 0 0 0 0 0 0 0 0 Page 78 DDS 4 SCSI Interface Manual Rev B Disconnect Reconnect Page Field Descriptions The following table describes the fields in the Disconnect Reconnect page Field Name Page Code Page Length Maximu m Burst Size DTDC Bytes 0 10
63. Disconnect message does not cause the Initiator to save the data pointer If Disconnect messages are used to break a long data transfer into two or more shorter transfers then a Save Data Pointer message is issued by the DAT drive before each Disconnect This message is sent from an Initiator to inform the DAT drive that an error such as a parity error occurred This message is sent from an Initiator to clear the present drive operation All pending data and status for the issuing Initiator are cleared and the drive goes back to Bus Free Phase No status or ending message is sent for the operation Any previously set modes are not changed This message is sent from the DAT drive to indicate the last message it received was inappropriate or was not implemented The DAT drive sends Message Reject and then goes to the Message In phase prior to requesting additional message bytes from the Initiator This sequence provides an interlock so the Initiator can determine which message was rejected This message is sent from an Initiator in response to a DAT drive request for a message when the Initiator does not currently have any other valid message to send This message is sent from the host to indicate that incorrect parity was detected See the following table This message is sent from the DAT drive to inform an Initiator that execution of a linked command is completed and that status was sent The Initiator can then set the pointers to
64. Excpt bits are set to one and Test Flag Number set to zero then the MODE SELECT command will return Check Condition with sense key set to Illegal Request and extended sense set to Invalid Field in Parameter List When the Test bit is set to one and the Test Flag Number is set to valid non zero value the drive will generate clear a test informational exception condition The value of the Test bit returned by a Mode Sense command will remain at zero The test action is based on the Test Flag Number value 1 to 64 This will set in the Log page the TapeAlert flag indicated by the Test Flag Number Once the TapeAlert flag is set it is processed normally based on the DExcpt MRIE Interval Count and Report Count values 1 to 64 This will clear the TapeAlert flag indicated by the absolute value of the Test Flag Number Clearing the flag in this way is equivalent to performing the specified corrective action for that flag thus allowing a real information exception condition to be set if the real error condition occurs for that flag 32767 OX7FFF This will set in the Log page all of the TapeAlert flags that are supported by the drive Once the supported TapeAlert flags are set they are processed normally based on the DExcpt MRIE Interval Count and Report Count values MRIE Default set to 3h This field indicates the method used by the drive to report informational exception conditions If the informational exception condition was generate
65. IUM Command Descriptor Block The following table shows the layout of the CDB Bits Byte 7 6 5 4 3 2 1 0 0 1 0 0 0 1 1 0 1 LUN 0 0 0 0 0 2 0 0 0 0 0 0 0 0 3 0 0 0 0 0 0 0 0 4 0 0 0 0 0 0 0 0 5 Source Address 6 0 0 0 0 0 0 0 0 7 0 0 0 0 0 0 0 1 8 0 0 0 0 0 0 0 0 9 Source Destination 10 0 0 0 0 0 0 0 0 11 vendor unique 0 0 0 0 Flag Link This vendor unique field is reserved and must be set to zero Command Descriptor Block Field Descriptions The source address field specifies the location from which the cartridge is taken the destination address field specifies the location to which the cartridge is moved The destination address must represent an empty storage element the cartridge in the drive is first moved to this location The source address must represent a full storage element this cartridge is then moved to the drive The following table shows the addresses of the various elements Source Source Destination Destination Element Address 0 0 1 Drive 2 Magazine slot 1 3 Magazine slot 2 4 Magazine slot 3 5 Magazine slot 4 6 Magazine slot 5 7 Magazine slot 6 Commands Exchange Medium A6h Page 39 Completion Status The following table lists the completion status for the EXCHANGE MEDIUM command Code Message Description 00h Good The cartridges have been moved to the specified destinations Status the cartridge in the drive is positioned at BOT The drive is ready for another comm
66. Identify Ignore Wide Residue Initiator Detected Error Linked Command Complete Vendor unique commands Seek Block Linked Command Complete with flag Message Reject No Operation Parity Error Message Save Data Pointer Synchronous Data Transfer Request Wide Data Transfer Request Request Block Address SCSI Bus Protocol Communication on the SCSI bus occurs between a host computer s SCSI controller and a peripheral controller The host controller is the nitiator and the peripheral device is the Target Some SCSI bus functions are assigned to the Initiator and others to the Target The Initiator arbitrates enters the Arbitration Phase of operation for control of the SCSI bus and enters the Selection Phase to select a specific Target such as a DAT drive The Target drive can request transfer of command data status information or disconnect from the bus While the tape drive is disconnected the bus is free to accomplish other tasks While disconnected the Target drive can process information obtained from the bus If the Target wants to reconnect it arbitrates for bus control For example a Target can reselect an Initiator or another Target to continue an operation SCSI Interface Description Page 7 Data transfer operations on the SCSI bus are either asynchronous or synchronous Asynchronous data transfer operations follow a defined request acknowledge REQ ACK handshake protocol Two eight bit bytes of information can b
67. List Length must be set to 0 Page 52 DDS 4 SCSI Interface Manual Rev B The drive presets the values as follows e The default accumulated values are set to all Os e The default threshold values are set to all 1s The default values cannot be changed If the host issues a LOG SELECT command with the PC bit specifying default values when the parameter list length is nonzero a Check Condition is returned The sense data is set to Illegal Request Invalid Field in the CDB The Parameter Control bytes of each parameter are preserved when the LOG SELECT command is issued with the PC bits specifying either of the default values SETTING ACCUMULATED VALUES DIRECTLY The host can set the accumulated values of pages 2 and 3 to any value by specifying the accumulated values in the PC bits and transferring the log parameters containing the new values and the Parameter Control bytes This ability to manually set the accumulated values allows the original counts previously read with the LOG SENSE command to be restored Thus the drive can continue to accumulate counts after a Bus Reset Bus Device Reset or a manual power cycle SETTING THE THRESHOLD VALUES DIRECTLY The host can set the threshold values of pages 2 and 3 to any value by specifying the threshold values in the PC bits and transferring the log parameters containing the new values and the Parameter Control bytes The threshold value is used in conjunction with the Log Paramet
68. MC LBIN O LP 0 5n 2 Parameter Length 1 5n 3 Value of Flag set when bit 0 1 There are 64 Tape Alert flags for drives and autoloaders Some are reserved The following table lists the flags supported by the drive Read Warning The tape drive is having problems reading data No data has been The drive is having lost but there has been a reduction in the performance of the tape severe trouble reading Write The tape drive is having problems writing data No data has been The drive is having Warning lost but there has been a reduction in the capacity of the tape severe trouble writing 3 Hard Error WwW The operation has stopped because an error has occurred while The drive had a hard read reading or writing data that the drive cannot correct or write error 4 C Your data is at risk Media can no longer be 1 Copy any data you require from this tape written read or 2 Do not use this tape again a is severely 3 Restart the operation with a different tape supplier helpline read data from the tape Write Failure C The tape is from a faulty batch or the tape drive is faulty The drive can no longer 1 Use a good tape to test the drive write data to the tape 2 If the problem persists call the tape drive supplier helpline 7 The tape cartridge has reached the end of its calculated useful life The media has exceeded Not Data Grade Write Protect 1 Copy any data you need to another tape its specified life 2 Discard the old tape
69. OCATE Block Address From BT bit Tape Position 1 BOT ON C 1 EOD ON C 1 BOT OFF A 1 EPD OFF A 4 BOT ON D 4 EOD ON D 4 BOT OFF B 4 EOD OFF B Commands Locate 2Bh Page 49 Completion Status The Completion Status for the LOCATE command is shown in the following table Code Message Description 00h Good The tape is positioned to the logical block address specified Status The drive remains in any previously set mode The drive is ready to perform any appropriate command 02h Check Extended Sense Byte 02h Condition Code Message Description 02h Not Ready No cartridge is inserted in the drive 04h Hardware Error Parity error on SCSI bus or drive hardware failure detected 05h Illegal Request An illegal partition number is requested The CDB contains an invalid bit CP bit is set when a single partition tape is installed 06h Unit Attention The cartridge was changed prior to accepting this command The drive was reset prior to this command 08h Blank Check The specified logical block address was not found on tape Tape is positioned at EOD That is it is positioned after the last filemark or set mark of the current partition The next WRITE command appends data to the tape Page 50 DDS 4 SCSI Interface Manual Rev B LOG SELECT 4Ch The LOG SELECT and LOG SENSE commands are used in conjunction with each other These commands allow the host to obtain and control statistical information about cartridge
70. SS Seagate DDS 4 and DAT 72 Tape Drives and Autoloaders Copyright 2003 Certance LLC All rights reserved Part Number 50000697 June 2003 Rev B Certance and the Certance logo are trademarks of Certance LLC Seagate is a trademark of Seagate Technology LLC Other product names are trademarks or registered trademarks of their respective owners Certance reserves the right to change without notice product offerings or specifications No part of this publication may be reproduced in any form without written permission from Certance LLC Important Information About This Manual All information contained in or disclosed by this document is considered proprietary by Certance By accepting this material the recipient agrees that this material and the information contained therein are held in confidence and in trust and will not be used reproduced in whole or in part nor its contents revealed to others except to meet the purpose for which it was delivered It is understood that no right is conveyed to reproduce or translate any item herein disclosed without express written permission from Certance Certance provides this manual as is without warranty of any kind either expressed or implied including but not limited to the implied warranties of merchantability and fitness for a particular purpose Certance reserves the right to change without notification the specifications contained in this manual Certance assumes no respon
71. T SENSE 03h The REQUEST SENSE command causes the drive to transfer status data to the Initiator pertaining to the last command REQUEST SENSE Command Descriptor Block The following table shows the layout of the CDB Bits Byte 7 6 5 4 3 2 1 0 0 0 0 0 0 0 0 1 1 1 0 0 0 0 0 0 0 0 2 0 0 0 0 0 0 0 0 3 0 0 0 0 0 0 0 0 4 Allocation Length 5 vendor unique 0 0 0 0 Flag Link This vendor unique field is reserved and must be set to zero Sense Data is updated with each command therefore the sense data only reports the status of the immediately previous command If a Check Condition status results a REQUEST SENSE command should be issued to recover the information form the Sense Data The REQUEST SENSE command returns Check Condition status only if a fatal error occurs during execution of the REQUEST SENSE command If nonfatal errors occur during the REQUEST SENSE execution Good Status is returned Sense Data may be invalid following a fatal error on a REQUEST SENSE command Sense Data Format The following table shows the format for the sense data Bits Byte 7 6 5 4 3 2 1 0 0 Valid Error Code 1 0 0 0 0 0 0 0 0 2 FM EOM ILI 0 Sense Key 3 MSB Residual Length 0 4 Residual Length 0 5 Residual Length 0 6 Residual Length LSB 0 7 Additional Sense Length 8 0 0 0 0 0 0 0 0 9 0 0 0 0 0 0 0 0 10 0 0 0 0 0 0 0 0 11 0 0 0 0 0 0 0 0 12 Additional Sense Code 13 Additional Sense Code Qualifier 14 0 0 0 0 0 0
72. T drive When Identify is sent from the drive to an Initiator during reconnection an implied Restore Pointers message is performed by the Initiator prior to completion of this message The following table describes the operation for each of the possible cases of parity error State or Phase Bus Free State Arbitration Phase Selection Phase Selection Message Out Phase Identify Message Reselection Message In Phase Identify Message Description The drive does not detect nor react to parity errors on the SCSI bus while the drive is in a bus free state The drive does not detect nor react to parity errors on the SCSI bus while arbitration is being performed The drive does not detect nor react to parity errors on the SCSI bus while the drive is being selected If the drive detects a parity error while the host is sending an Identify message the drive will attempt one retry then go to Bus Free If the drive is attempting to reconnect to the host and the host asserts ATN because it detected an error the drive e Switches the host to the Message Out Phase e Waits for the host to send a 09 Parity Error Message The drive then performs the retry option by e Switching the host to the Message In Phase e Resending the Identify Message SCSI Interface Description State or Phase Command Phase Data In Phase Data Out Phase Status Phase Message In Phase Page 21 Description If the drive detects a pari
73. Tagged Queuing is disabled DQUE Data Compression Control Page 0Fh The Data Compression DC Control page returns the last values set by the host with a MODE SELECT command for data compression control Also refer to the MODE SELECT command Data Compression Control page The following table illustrates the DC Control page Bits Byte 7 6 5 4 3 2 1 0 0 0 0 0 1 1 1 1 Page Length OEh DCE DCC 0 0 0 0 0 DDE RED 0 0 0 0 Compression Algorithm Compression Algorithm Compression Algorithm zl o or A N oO Compression Algorithm Page 96 DDS 4 SCSI Interface Manual Rev B Byte 10 11 12 13 14 15 Bits ojojo o ojojo jo bei Kai Kail A 3 2 1 0 Decompression Algorithm Decompression Algorithm Decompression Algorithm Decompression Algorithm 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 DC Conirol Page Field Descriptions The following table describes the fields in the DC Control page Field Name DCE DCC RED Compression Algorithm Decompressi on Algorithm Bytes 2 Bits 7 Description The DCE Data Compression Enable bit controls data compression This bit contains the last value set by the host with a MODE SELECT command If the value is 1 the drive compresses data received from the host during a WRITE command before it writes the data to tape in the DDS DC format If the value is 0 the drive does not compress data sent during a WRITE command and the h
74. These counts cannot be changed by the initiator When the cartridge is ejected or the UNLOAD command is received the current usage counts are saved in the previous counts The total counts are also updated to indicate the new totals This updated data is written to the tape in the Tape Log area The Tape Log data is not cleared by any reset and cannot be changed with the LOG SELECT command Note If power is lost before the update data is written to the tape the Tape Log area is not updated Also if the cassette is write protected the Tape Log area is not updated when the cassette is ejected The drive does NOT post a Check Condition for this case Each page 30 count is a positive binary value The counts do not overflow Once a count reaches its maximum value that maximum value is always returned The counts do not roll over at the maximum value A single partition tape contains one Tape Log a dual partition tape contains two Tape Logs The appropriate Tape Log is returned as determined by the previously selected partition The page 30 parameter codes are listed in the following table indicates that the most significant 4 bits are 0 Name Code Length Description Current 0001 3 This count is the number of groups written to the partition since Groups the cartridge was inserted Each group contains 126 KB of Written data Current 0002 2 This count is the number of rewritten frames within the Rewritten partitions since the cart
75. VER cause automatic loading e Ejection of a cleaning cassette after cleaning failed e Ejection of a data cassette by a SCSI Move Medium command e Ejecting the last cassette in the magazine i e the cassette in the highest numbered occupied slot Magazine Ejection The Eject button on the Autoloader can be used in two modes regular and emergency eject When the button is pressed for less than five seconds a regular eject begins The current SCSI command is completed and buffered data is written to the tape Pending commands are terminated with Not Ready Operator Medium Removal Request 02 5A 01 status the cassette is returned to its slot in the magazine and the magazine is ejected If the Eject button is held for more than five seconds emergency eject begins All commands are terminated within 35 seconds the cassette in the drive is placed in the magazine and the magazine is ejected If there is no cassette in the drive magazine ejection will occur immediately Pending commands are terminated with Not Ready Operator Medium Removal Request 02 5A 01 status Caution If the eject button is pressed for an emergency eject while a write operation is in progress the tape may not be appendable Stray Tape Recovery If the magazine is forcibly removed from the loader while it is powered off a stray tape may be left in either the drive or the elevator In this case the recovery procedure is to insert an empty magazine in
76. a 12 slot magazine Element Status Data 8 byte header Medium Transport Element changer Page 8 byte header Medium Transport element Descriptor 12 bytes Storage element Page 8 byte header Storage Element Descriptors 12 bytes each for a six slot magazine 72 bytes Data Transfer Element drive Page 8 byte header Data Transfer Element Descriptor 12 bytes Element Status Data Header The following table shows the header for the element status data returned from the drive Bits Byte 7 6 5 4 3 2 1 0 0 0 0 0 0 0 0 0 1 First element Address Reported 2 MSB Number of elements available 3 LSB Number of elements available 4 0 0 0 0 0 0 0 0 5 MSB Byte Count of Report Available 6 Byte Count of Report Available 7 Byte Count of Report Available LSB 8 Element Status Page n Element Status Page The first element address reported field indicates the element address of the element with the smallest element address found to meet the CDB request Refer to the MOVE MEDIUM command for the addresses of the various elements The number of elements field indicates the number of elements meeting the request in the CDB The status for these elements is returned if sufficient allocation length is specified The byte count of report available field indicates the number of bytes of element status page and descriptor data available for all elements meeting the request in the CDB This value is not adjusted to match the allocation length
77. a series of linked ate Status commands except the last command unless an error exception or abnormal condition causes either Check Condition or Reservation Conflict status to be set If this status is not returned the chain of linked commands is broken and no further commands in the series are executed Reser Ch 18h This status is returned when a device attempts to access a DAT vation drive when it is reserved for access to another device Conflict Page 24 DDS 4 SCSI Interface Manual Rev B Attention Condition The Attention Condition allows an Initiator to inform a Target that the Initiator has a message to send The DAT drive may read this message at its convenience by performing a Message Out phase The Initiator creates the Attention Condition by asserting the ATN signal at any time except during the Arbitration or Bus Free phases The DAT drive checks to see if ATN is set at every phase change If ATN is set the drive goes into the Message Out phase The Initiator may de assert the ATN signal at any time Normally the Initiator de asserts ATN during or before the last REQ ACK handshake of the Message Out phase The Attention signal must be present prior to a phase change to allow the DAT drive time to respond with a Message Out phase at the phase change Reset Condition The Reset Condition takes precedence over all phases and conditions and is used to immediately terminate operation and clear all SCSI devices from the bu
78. a total of e Al user data e ECC frames e Other structures in the group data as defined by the DDS format The total uncorrectable errors count is a tabulation of the times the drive could not correct a write error by any means including the rewrite retry limit being exceeded The rewrites since last read type operation count is similar to the total rewrite count 0002 except the counter is set to 0 in two cases e When the operation is changed to a read type operation e When a rewind operation is performed Read Error Counts page 3 Page 3 contains the Read Error counts which are tabulations of any errors encountered while reading the tape these tabulations include possible errors from media access commands The page 3 parameter codes for read errors are listed in the following table Parameter Code Length Name 0002 2 Total rereads 0003 3 Total errors corrected 0004 2 Total correctable ECC C3 errors 0005 8 Total bytes processed read 0006 2 Total uncorrectable errors 8007 2 Rereads since last write type operation The total reread count is incremented each time the tape is repositioned to reread a frame from the tape Page 64 DDS 4 SCSI Interface Manual Rev B The total errors corrected count is incremented each time the drive recovers from a read error This count includes the reread count and all C3 ECC errors that could be corrected Note This count does NOT include any frames read that were rewritte
79. ability If the value is 1 read after write check and rewrites are disabled If the value is 0 read after write is enabled The default value is 0 The EN C3 Enable C3 bit enables and disables C3 ECC code generation during writing if the value is 1 C3 ECC code is generated during writing if the value is 0 c8 ECC code is not generated The default value is 1 The N Group field specifies the number of repeats of each tape group to record Values greater than 0 can be used to increase reliability The default value is 0 The Active Partition field is set to the active partition either 00h or 01h The default is 0 The first partition on a dual partition tape is partition 1 The Write Delay Time field indicates the maximum time in multiples of 100 milliseconds which the drive waits with a partially full buffer before recording the data to tape The default value is 258h indicating a 60 second delay Not supported always 1 The Report Setmarks RSMK bit determines whether or not the drive recognizes setmarks If the value is 1 the drive recognizes and reports setmarks during appropriate read and space operations The default value is 1 If the value is 0 the drive ignores setmarks It skips setmarks as if they do not exist The Report Early Warning REW bit determines whether or not the drive reports an early warning condition for read operations For read type operations if this bit is 0 the drive does not report the
80. ag Link This vendor unique field is reserved and must be set to zero Command Descriptor Block Field Description The following table defines the fields in the CDB Field Name Bytes Bits Description Allocation 3 4 The drive returns 8 bytes of data with results from the last self test Length The following table shows the Diagnostic parameter values Value Description 00 Page code 80h 01 Reserved 00h 02 Reserved 00h 03 Additional length 04 04 Last successful test 05 Error code 06 FRA 07 Tape load count If the Enhanced Diagnostics were not invoked before the RECEIVE DIAGNOSTIC RESULTS command the last successful test field byte 4 is set to O If the Enhanced Diagnostics were invoked before the RECEIVE DIAGNOSTIC RESULTS command the last successful test field byte 4 is set to 7 If a failure Commands Receive Diagnostic Results 1Ch Page 125 occurred during one of the tests byte 4 is set to the previous test that passed successtully If no errors occurred during the Enhanced Diagnostics or the Enhanced Diagnostics were not invoked the Error code field byte 5 is set to 0 If an error occurred during the testing byte 5 will contain the Vendor specific Code Qualifier the meaning of which is defined in the Request Sense Command The FRA field byte 6 of the Diagnostics data is set as follows FRA Indication 0 No errors ni BDrveemos a a aS 2 Fautpmeia SoS 3 Power supply or cable prob
81. an the Available Length plus 4 the drive returns a Check Condition status with a Sense Key of Illegal Request WRITE DATA BUFFER Data Header The following table shows the layout of the data header Block Bits Byte 7 6 5 4 3 2 1 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 2 0 0 0 0 0 0 0 0 3 0 0 0 0 0 0 0 0 Page 166 DDS 4 SCSI Interface Manual Rev B Completion Status The Completion Status for the WRITE DATA BUFFER command is shown in the following table Code Message Description 00h Good e f Mode 0 The Data Header is accepted and verified if correct the data Status is accepted and written to the buffer at offset 0 the transfer length is the sum of the four byte header and the data to be written in the buffer f Mode 2 the data is written to the buffer starting at the specified offset f Mode 4 the micro code data is transferred to the buffer at the specified offset e f Mode 5 The micro code data is transferred to the buffer at the specified offset a zero length transfer is not an error and if there are no validation errors the micro code in the buffer is saved in the drive s flash memory 02h Check Extended Sense Byte 02h Condition Code Message Description 04h Hardware Error Drive hardware failure detected 05h Illegal Request The CDB contains an invalid bit Transfer Length exceeds the maximum if MODE 0 The download file is invalid if MODE 5 The additional sense code and quali
82. and 02h Check Extended Sense Byte 02h Condition Code Message Description 02h Not Ready No magazine is present 04h Hardware Error Parity error on SCSI bus or drive hardware failure detected 05h Illegal Request The source element is empty The drive is empty The destination element is full The source and destination address are the same 06h Unit Attention Cartridge was changed prior to accepting this command Drive was reset prior to this command Page 40 DDS 4 SCSI Interface Manual Rev B INITIALIZE ELEMENT STATUS AutoLoader Only 07h The INITIALIZE ELEMENT STATUS command causes the AutoLoader to eject the cartridge that is in the DAT drive if any and return it to the slot in the magazine Then the magazine is initialized checking each element for cartridges or any other status relevant to that element This command performs the same magazine initialization as is performed by mounting a magazine and powering up the drive except that no cartridge is inserted into the drive INITIALIZE ELEMENT STATUS Command Descriptor Block The following table shows the layout of the CDB Bits Byte 7 6 5 4 3 2 1 0 0 0 1 0 0 0 1 1 1 Hr UN o o o Oo Oo 2 0 0 0 0 0 0 0 0 3 o o o o o 0o O0 0o a o o o o B 0 O0 Oo 5 vendor unique 0 0 0 0 Flag Link This vendor unique field is reserved and must be set to zero Completion Status The following table lists the completion
83. and and in variable with the transfer allocation length of READ and WRITE commands The use of the MODE SENSE command determines the current block size The READ BLOCK LIMITS command indicates the minimum and maximum block size that the drive can support Because the MODE SELECT block descriptor block size field is 3 bytes in length the drive is logically limited to this imposed limit Therefore the maximum block size is ffffff hexadecimal or 16 777 215 bytes in length Commands Read Block Limits 05h Page 111 Completion Status The Completion Status for the READ BLOCK LIMITS command is shown in the following table Code Message Description 00h Good e The drive is ready to perform any appropriate command Status e The drive remains in any previously set mode e The tape position is not changed 02h Check Extended Sense Byte 02h Condition Code Message Description 02h Not Ready No cartridge is inserted in the drive 04h Hardware Error Drive hardware failure detected 05h Illegal Request The CDB or Parameter List contains an invalid bit 06h Unit Cartridge was changed prior to accepting Attention this command The drive was reset prior to this command Page 112 READ DATA BUFFER 3Ch DDS 4 SCSI Interface Manual Rev B The READ DATA BUFFER command returns the 4 byte Read Buffer header plus the number of bytes specified by the allocation Length field This command is used in conjunction with the WRITE DATA BUFFER
84. and the information field will contain the residual count of all blocks not written to tape Command Descriptor Block field description The following table defines the fields in the CDB Field Name Bytes Bits Description Fixed 1 0 If this bit is O the transfer length contains the number of bytes in the Block block IF this bit is 1 blocks are of fixed size as specified by the MODE Size bit SELECT Block Descriptor Transfer 2 4 0 7 These fields specify the number of bytes or blocks to be written at the Length current tape position if Fixed 0 Completion Status The Completion Status for the WRITE command is shown in the following table Commands Write OAh Page 163 Code Message Description 00h Good e The SCSI data has been transferred to the data buffer Status e The drive remains in any previously set mode 02h Check Extended Sense Byte 02h Condition Code Message Description 02h Not Ready No cartridge is inserted in the drive 03h Media Error Unrecoverable data error encountered Possibly bad cartridge 04h Hardware Error Drive hardware failure detected 05h Illegal Request The CDB contains an invalid bit 06h Unit Cartridge was changed prior to accepting Attention this command The drive was reset prior to this command 07h Write Protect The tape is write protected check the cartridge before continuing ODh Volume Overflow WRITE command completed with data in the buffer because the end of partition was
85. ands Page 35 Conventions The commands in this chapter are listed in alphabetical order Each command is described its Command Descriptor Block CDB illustrated and the Completion Status is given Bits and fields defined in the ANSI SCSI 2 document that are not used by the drive are not described in this document Rather those bits and fields are shown as 0 1 or X ignores as appropriate Bits and fields that are supported by the drive are described Command Descriptor Blocks CDBs A host makes request of the DAT drives by sending a command descriptor block CDB some commands also require a parameter list If the CDB or the parameter list contains an invalid parameter the drive terminates the command without altering the medium Command Descriptor Block Formats The SCSI 2 six byte CDBs are arranged in the format shown in the following table Bits Byte 7 6 5 4 3 2 1 0 0 Group Code Command Code 1 LUN Command Dependent 2 Command Dependent 3 Command Dependent 4 Command Dependent 5 vendor unique 0 0 0 0 Flag Link The SCSI 2 ten byte CDBs are arranged in the format shown in the following table Bits Byte 7 6 5 4 3 2 1 0 Group Code Command Code LUN Command Dependent Command Dependent Command Dependent Command Dependent Command Dependent Command Dependent Command Dependent Command Dependent Vendor Unique 0 0 0 0 Flag Link Oojo NI ojla AR oJ N o Page 36 DDS 4 SCSI Interface Manual Rev B Com
86. ape to block locations greater or less than the current block position Positioning is done with a high speed search and does not require a sequential read for the requested block The Initiator may obtain block addresses through the REQUEST BLOCK ADDRESS command as part of its tape write procedures The block addresses can in turn be recorded in a user defined directory When there is no exception condition during a SEEK BLOCK command the tape is logically positioned before the block specified in the block address The first logical block on tape is block 1 therefore a zero in the block address is considered an error SEEK BLOCK Command Descriptor Block The following table shows the layout of the CDB Bits Byte 7 6 5 4 3 2 1 0 0 0 0 0 0 1 1 0 0 1 0 0 0 0 0 0 0 IMMED 2 MSB Block Address 3 Block Address 4 Block Address LSB 5 vendor unique 0 0 0 0 Flag Link This vendor unique field is reserved and must be set to zero Command Descriptor Block Field Description The following table provides descriptions of the CDB fields Field Name Bytes Bits Description IMMED 1 0 If this bit is 1 the status is returned as soon as the operation is initiated If this bit is 0 the status is returned after the tape is positioned at the specified block Block 2 4 These fields specify the address of the block to which the tape is to be Address positioned Commands Seek Block 0Ch Page 151 Completion Status The
87. ardware failure 4 51 00 Erase failure 4 53 00 Media load or eject failure 4 53 01 Unload tape failure 5 Illegal Request 5 1A 00 Parameter list length error 5 20 00 Invalid command operation code 5 21 01 Invalid element address loader 5 24 00 Invalid field in CDB 5 25 00 Logical unit not supported 5 26 00 Invalid field in parameter list 5 26 01 Parameter not supported 5 26 02 Parameter value invalid 5 26 03 Threshold parameters not supported 5 39 00 Saving parameters not supported 5 3A 00 Medium or magazine not present 5 3B oD Medium destination element full loader 5 3B 0E Medium source element empty loader 6 Unit Attention 6 28 00 Not ready to ready change 6 29 00 Power on reset or bus device reset occurred 6 29 01 Power on occurred 6 29 02 SCSI bus reset occurred 6 29 03 Bus device reset function occurred 6 29 04 Device internal reset micro code load reboot 6 29 05 Transceiver mode changed to single ended 6 29 06 Transceiver mode changed to LVD 6 2A 01 Mode parameters changed 6 3F 01 Micro code has been changed 6 5A 01 Operator medium removal request 6 5B 01 Threshold condition met 6 5D 00 Tape Alert Flag threshold exceeded 6 5D FF Tape Alert Flag tested 7 Data Protect 7 27 00 Write protected 7 30 00 Incompatible medium installed non MRS 8 Blank Check 8 00 05 End of data detected 8 14 03 End of data not found 8 30 01 Incompatible medium installed unrecorded or unknown format 8 30 02 Cann
88. are failure detected 05h Illegal Request The CDB contains an invalid bit 06h Unit Cartridge was changed prior to accepting Attention this command The drive was reset prior to this command 08h Blank Check The drive encountered EOD Page 110 DDS 4 SCSI Interface Manual Rev B READ BLOCK LIMITS 05h The READ BLOCK LIMITS command causes the drive to transfer the block length limits to the Initiator The minimum block length is 1 byte the maximum is 224 1 bytes The minimum and maximum block limits are returned to the Initiator in a six byte data string READ BLOCK LIMITS Command Descriptor Block The following table shows the layout of the CDB Byte Bits 7 6 5 4 3 2 1 0 0 0 0 0 0 0 1 0 1 1 0 0 0 0 0 0 0 0 2 0 0 0 0 0 0 0 0 3 0 0 0 0 0 0 0 0 4 0 0 0 0 0 0 0 0 5 vendor unique 0 0 0 0 Flag Link This vendor unique field is reserved and must be set to zero Command Descriptor Block Field Description The Command Descriptor Block does not contain command dependent fields The values of the individual bytes in the Block Length fields are shown in the following table in hexadecimal notation Bits Byte 7 6 5 4 3 2 1 0 0 0 0 0 0 0 0 0 MSB Maximum Block Length FFH Maximum Block Length FFh Maximum Block Length LSB FFh MSB Minimum Block Length 00h Minimum Block Length LSB 01h aj A OJ N o Block Size Definition The host specifies the actual block size in fixed mode with the MODE SELECT comm
89. ata blocks REPORT DENSITY Response Data The response data for the REPORT DENSITY SUPPORT command contains e A four byte Report Density Support Header e One or more Report Density Support Data Block Descriptors The density support data blocks follow the header The density support data blocks are in numerical ascending order of the primary density code value Commands Report Density Support 44h Page 129 REPORT DENSITY SUPPORT Header The following table shows the header layout for the REPORT DENSITY SUPPORT command Bits Byte 7 6 5 4 3 2 1 0 0 1 Available density support length n Reevwed 3 Reserved The AVAILABLE DENSITY SUPPORT LENGTH field specifies the number of bytes in the following data that are available to be transferred The available density support length does not include itself This field is equal to 2 more than an integer multiple of 52 the length in bytes of a density support data block descriptor REPORT DENSITY SUPPORT Data block descriptor Bits Byte 7 6 5 4 3 2 1 0 0 Primary Density Code 1 Secondary Density Code 2 WRTOK DUP DEFLT Reserved 3 Reserved 4 Resewed n 5 7 Bits per mm 8 9 Media Width 10 11 Tracks 12 15 Capacity 16 23 Assigning Organization 24 31 Density Name 32 51 Description DENSITY SUPPORT Data Block Descriptor Field Descriptions Field Name Bytes Bits Description Primary 0 This contains a value returned by a Mode Sense command for the density density describe
90. ata format was encountered on tape The drive aborted the command This key is returned if a bus parity error is detected The Initiator may be able to recover by trying the command again The drive reached the physical EOT and write data remains in the buffer The source data did not match the tape data during a VERIFY command Additional Sense Code and Code Qualifier Additional sense codes and code qualifiers are returned in the REQUEST SENSE data in bytes 12 and 13 These byte codes are loaded whenever a Check Condition is returned for any SCSI CDB The purpose of the codes is to further define the cause of an error represented in the REQUEST SENSE Data Sense Key Page 136 DDS 4 SCSI Interface Manual Rev B The following table lists the additional sense code and code qualifiers Byte 2 Sense Byte 12 Byte 13 Definition Key ASC ASCQ Additional sense code 0 No Sense 0 00 00 No additional sense information 0 00 01 Filemark detected 0 00 02 End of partition medium detected 0 00 03 Setmark detected 0 00 04 Beginning of partition media detected 0 00 17 Cleaning requested 0 5D 00 Tape Alert Flag threshold exceeded 0 5D FF Tape Alert Flag tested 1 Recovered Error 1 18 01 Recovered data with error condition and retries applied 1 37 00 Rounded parameter 1 5B 00 Log exception 1 5B 02 Threshold condition met 1 5D 00 Tape Alert Flag threshold exceeded 1 5D FF Tape Alert Flag tested 2 Not Ready 2 0
91. ation 32 Cassette Selection siiani diii aido da eene nnne nnns nnne 32 Automatic Loading Mode estiren her enke e ENE SEER A EAEE EEEE SEERE 32 Magazine E Le 33 Stray Tape Recovery sssssssssssssseeeenneeeen nennen enne nennen snnt enne 33 34 dgigeje Pert 34 Command Reference Let 34 ele EE 35 Command Descriptor Blocks CDe 35 Command Descriptor Block Fomate 35 Command Descriptor Block Field Descriptions sssssssssss 36 Flag and Link Bit Descriptions ssseeeeeeeenm RART SE EKRANA 36 SENS AE D eh eei sf I LR LEE LL dE ae EE LIE 37 Contents Pagev ERASE Command Descriptor Block 37 Command Descriptor Block Field Description 37 Completion Status s oet a rei ed eerie Ore oi e aide 37 EXCHANGE MEDIUM AutoLoader Only A n 39 EXCHANGE MEDIUM Command Descriptor Block sess 39 Command Descriptor Block Field Descriptions sssssessss 39 Completion Status esssssssssssseseeeeee nennen en nennen snnt nnne 40 INITIALIZE ELEMENT STATUS AutoLoader Only 07h sss 41 INITIALIZE ELEMENT STATUS Command Descriptor Block 41 Gompletion Status edid eet t Ft e tiere ER Has ie Pep ead dE aa 41 INQUIRY 42H idi Eee ee Ee dea cy Pet iv al 42 INQUIRY Command Descriptor Block 42 Command Descriptor Block Field De
92. ational exception conditions Perf Default set to 0 When this bit is set to zero this indicates that informational exception operations that can cause delays are acceptable When this bit is set to one the drive shall not cause delays while doing informational exception operations In Scorpion 40 there is no significant performance impact from Tape Alert operations Test Default set to 0 When this bit is set to zero this indicates that the drive shall not generate any false test informational exception conditions When this bit is set to one and Test Flag Number is set to zero the drive will generate a false informational exception condition based on the MRIE field the Interval Timer field is ignored and the Report Count field is used as the Test Flag Number When a false information exception condition is posted the TapeAlert flags in the Log page are not modified However real informational exception conditions have priority over false informational exception conditions The Test bit will be automatically cleared when the false information exception condition is posted on the first command excluding Inquiry and Request Sense that is received with no real information exception condition pending The false informational exception condition will then be reported in the method specified by the MRIE value except with the additional sense code set to Ox5DFF If both the Page 86 DDS 4 SCSI Interface Manual Rev B Test and D
93. bi mM Oo 0 Drive Serial Number Drive Serial Number Data Format Field Descriptions The following table defines the fields in the Drive Serial Number Data Format Field Name Bytes Bits Description Peripheral 0 0 7 This field is set to 01h to indicate a sequential Device Type access device Page Code 1 0 7 The Page Code field is set to 80h to indicate that the data following contain the Drive Serial Number Page Length 3 0 7 This field specifies the length of the Drive Serial Number Drive s Serial 4 10 0 7 This field contains the drive s alohanumeric serial Number number Completion Status The Completion Status for the INQUIRY command is shown in the following table Code Message Description 00h Good Status The tape is not moved the current position is maintained The drive remains in any previously set modes The drive is ready to perform any appropriate command 02h Check Condition Extended Sense Byte 02h Code Message Description 04h Hardware Error Parity error on SCSI bus or drive hardware failure detected 05h Illegal Request The CDB contains an invalid bit Commands Load Unload 1Bh Page 45 LOAD UNLOAD 1Bh The LOAD UNLOAD command requests that the DAT drive enable or disable the logical unit for further operations When a LOAD command is executed the tape is positioned to LBOT and made ready for the next command When an UNLOAD command is executed the tape positions to BOT a
94. ceeds to the Command Out phase to request the next CDB Command linking continues as long as the Link bit is set in successive CDBs Linking stops when the drive detects an error and posts a Busy or Check Condition The Flag and Link bits are used by all commands These bits are defined in the following table If the and the Link bit Flag bit is is the resultis 1 0 The Target sends an Intermediate Good Status then a Linked Command Complete message and then requests the next command 1 1 The Target returns Immediate Status and then sends a Linked Command Complete with flag message then requests the next command 0 0 The Target performs normal termination and goes to Bus Free 0 1 Invalid the Target returns Illegal Request Commands Erase 19h Page 37 ERASE 19h The ERASE command creates an EOD end of recorded data marker at the current position of the tape when the command is issued thus rendering the remainder of the tape unreadable ERASE Command Descriptor Block The following table shows the layout of the CDB Bits Byte 7 6 5 4 3 2 1 0 0 0 0 0 1 1 0 0 1 1 0 0 0 0 0 0 IMMED Long 2 0 0 0 0 0 0 0 0 3 0 0 0 0 0 0 0 0 4 0 0 0 0 0 0 0 0 5 vendor unique 0 0 0 0 Flag Link This vendor unique field is reserved and must be set to zero Command Descriptor Block Field Description The following table defines the fields in the CDB Field Name Bytes Bits Description IMMED 1 1 I
95. ch correlates to the primary density code as follows 25h DDS3 26h DDS4 47h DAT 72 This field contains descriptive ASCII data The Completion Status for the REPORT DENSITY SUPPORT command is shown in the following table Code Message 00h Good Status 02h Check Condition Description e The drive is ready to perform any appropriate command e The drive remains in any previously set mode e The tape position is unchanged Extended Sense Byte 02h Code 02h 04h 05h 06h Message Description Not ready Media bit 1 and drive not in ready state Hardware Drive hardware error detected during Error command execution Illegal The CDB contains an invalid bit request Unit Cartridge change prior to accepting the Attention command Drive reset prior to accepting the command Commands Request Block Address 02h REQUEST BLOCK ADDRESS 02h Page 131 The REQUEST BLOCK ADDRESS command requests the drive to transfer the current block address to the Initiator This command returns the block address number on tape REQUEST BLOCK ADDRESS Command Descriptor Block The following table shows the layout of the CDB Bits Byte 7 6 5 4 3 2 1 0 0 0 0 0 0 0 0 1 0 1 0 0 0 0 0 0 0 0 2 0 0 0 0 0 0 0 0 3 0 0 0 0 0 0 0 0 4 Allocation Length 5 vendor unique 0 0 0 0 Flag Link This vendor unique field is reserved and must be set to zero Command Descriptor Block Field Description The follow
96. ch particular log sense page Any attempt to specify an unused parameter causes a Check Condition The sense data is set to Illegal Request Invalid Field in the parameter list LOG SELECT Command Descriptor Block The following table shows the layout of the CDB Bits Byte 7 6 5 4 3 2 1 0 0 0 1 0 0 1 1 0 0 1 0 0 0 0 0 0 PCR 0 2 PC 0 0 0 0 0 0 3 0 0 0 0 0 0 0 0 4 0 0 0 0 0 0 0 0 5 0 0 0 0 0 0 0 0 6 0 0 0 0 0 0 0 0 7 MSB Parameter List Length 8 Parameter List Length LSB 9 vendor unique 0 0 0 0 Flag Link This vendor unique field is reserved and must be set to zero Commands Log Select 4Ch Page 51 Command Descriptor Block Field Description The following table defines the fields in the CDB Field Name Bytes PCR bit 1 PC bits 2 Parameter 7 8 List Length Description The Parameter Code Reset PCR bit is used to reset log parameters If the bit is set 1 and the parameter list length is set to O all accumulated values are set to 0 All threshold values are set to the defaults Pages 0 30 and 31 are not reset with this bit When the PCR bit is set the PC bits in the CDB are ignored A PCR bit of 0 does not cause the parameters to be reset The Page Control bits select one of four possible types of log information The settings of these bits are shown in a subsequent table The Parameter List Length field specifies the length in bytes of the parameter list to be transferred during
97. code format is shown in the following table A status byte is sent from the DAT drive to the Initiator during the Status phase at the termination of each command unless the command is cleared by an Abort message by a Bus Device Reset message or by a Reset condition BITS 7 6 5 4 3 2 1 Content 0 0 0 Status Code 0 The DAT drive uses the 4 bit status codes shown in the following table Bits 4 3 2 1 0 Definition 0 0 0 0 X Good Status 0 0 0 1 X Check Condition 0 1 0 0 X Busy 1 0 0 0 X Intermediate Status 1 1 0 0 X Reservation Conflict Descriptions of the five supported SCSI status codes are given in the following table Byte 0 Status Status Message Code Phase Definition Busy 4h 08h This status DAT drive busy is returned when the drive is unable to accept a command from the Initiator For example it is returned during an intermediate disconnect or after an immediate command has completed and the request function is not done The normal Initiator recovery action is to issue the command at a later time Check 1h 02h Any error exception or abnormal condition that causes the Condition sense data to be set causes a Check Condition status A REQUEST SENSE command should be issued following a Check Condition status to determine the nature of the condition Good Oh 10h This status indicates that the DAT drive successfully completed Status the command Intermedi 8h 10h This status is returned for every command in
98. commend using the 10 byte Reserve Unit Command since the older 6 byte command can only specify a Device ID in the range of 0 to 7 whereas the drive supports a Device ID in the range of 0 to 15 The drive reservation once established remains in effect until occurrence of one of the following e Another RESERVE UNIT command arrives from the same Initiator that requested the current reservation for itself or for a third party The new reservation supersedes the current one and may be the same as the current one Redundant use of the command is not considered an error e A RELEASE UNIT command arrives from the same Initiator that requested the current reservation The drive returns to unreserved mode e A Bus Device Reset Message arrives from any Initiator e A Reset condition occurs e Firmware is updated When the drive is reserved it returns Reservation Conflict Status in response to any and all commands received from excluded Initiators An exception to this is in response to the RELEASE UNIT command and in response to a subsequent RESERVE UNIT command from the original reservation requester Also see the RELEASE UNIT command In addition INQUIRY REQUEST SENSE PREVENT MEDIUM REMOVAL with a prevent bit of zero and RELEASE UNIT commands will be accepted from any initiator RESERVE UNIT Command Descriptor Block 6 byte version The following table shows the layout of the 6 byte CDB Bits Byte 7 6 5 4 3 2 1 0 0 0 0 0 1
99. ction Identify Message Because the drive only supports Logical Unit 0 the Identify message is used solely to specify the Disconnect option The bit map for the Identify message is as follows Bits 7 6 5 4 3 2 1 0 DIS Reserved LUN If bit 7 is set the Identify message is indicated Bit 6 shown as DIS is set as follows Q The host does not support disconnects The drive does not disconnect from the SCSI bus during the current command SCSI Interface Description Page 11 1 The host supports disconnects The drive disconnects from the SCSI bus appropriately for the command in progress to relinquish the bus for other units Note LUN 1 is legal for Autoloader drives only Information Transfer Phases The Command Data Status and Message Phases are grouped together as the Information Transfer Phases because they are all used to transfer data or control information on the SCSI bus The following table shows the Control Data C D Input Output I O and Message MSG signals used to distinguish between the various Information Transfer Phases The Target drives these three signals and thereby controls all changes from one phase to another Signals MSG C D I O Phases Direction of Transfer 0 1 1 1 Data Initiator to Target 1 1 0 Data Target to Initiator C D 1 0 1 Command Initiator to Target 1 0 0 Status Target to Initiator MSG 0 0 1 Message Initiator to Target 0 0 0 Message Target to Initiator Key
100. d Tape Alert Flags The DDS 4 and DAT 72 drive autoloader conform to the Tape Alert v3 0 Standard The Tape Alert Log page can only be accessed by the Log Sense commands there are no Log Select actions defined in the Tape Alert specification The log page is used in conjunction with the Tape Alert Mode Page that controls the action taken by the drive when a flag is set and sets various other control mechanisms of the Tape Alert system A flag is set whenever the condition for setting the flag exists There are three types of flags Informational Warning and Critical The type of flag depends upon the severity of the condition that sets the flag Flags are cleared on the following conditions e At drive power on e When the TapeAlert Log page is read e When specified corrective action has been taken such as using a cleaning cartridge e On a SCSI bus reset or bus device reset message e OnLog Select reset note that the recommended action on receiving Log Select for the TapeAlert Log page is to reject the command with an error Commands Log Sense 4Dh Page 65 Additional information regarding the Tape Alert system is found in the SCSI 3 Stream Commands SSC Standard Page 66 DDS 4 SCSI Interface Manual Rev B The format of the Tape Alert Log Page is shown below Bits Byte 7 6 5 4 3 2 1 0 0 1 0 0 0 0 0 0 0 0 2 MSB Page Length 140h 3 LSB 5n 1 MSB Parameter Code 5n LSB Parameter Code 5n 1 DU 0 DS 1 TSD 0 ETC 0 T
101. d a 40h Sense data meaning EOM and no Sense Key 4 Subsequent WRITE commands write data and complete with check condition with EOM Status and No Sense Key until the physical tape end is encountered Page 28 Error Reporting Soft Errors Hard Errors DDS 4 SCSI Interface Manual Rev B Soft errors are generally tape quality related and occur more frequently during write operations than during read operations Soft errors indicate repeated attempts by the drive to read or write data on the tape Some soft errors are normal but an increase in the usual count can indicate deteriorating tape quality If the soft error count remains higher than normal clean the read write heads If this procedure does not clear the problem change to a new tape cartridge If a hard error unrecoverable error occurs during operation the drive terminates operation immediately and returns a Check Condition The Initiator should cease any further read or write functions and issue a Request Sense Command to determine the type of error When the drive detects a write error it attempts to rewrite the data up to 127 times After the 127th attempt the error is considered unrecoverable and the operation terminates In that case the appropriate LED on the drive front panel flashes rapidly When a hard error is encountered replace the tape with a new cartridge and repeat the function or clean the heads with a cleaning cartridge Variable and Fixed Mode Recordin
102. d by an event that caused a real Check Condition to occur then this real Check Condition will override i e be used instead of the Check Condition defined in MRIE modes 1h to 5h The values defined for the MRIE field are 0x0 No reporting of informational exception conditions This method instructs the tape drive to not report information exception conditions 0x1 Asynchronous Event Reporting This method instructs the tape drive to report information exception conditions by using the rules for asynchronous event reporting as described in the SCSI 3 Architecture Model and the relevant protocol standard The sense key shall be set to RECOVERED ERROR and the additional sense code shall indicate the cause of the information exception condition which is 5DOOh for a Tape Alert event 0x2 Generate Unit Attention This method instructs the tape drive to report information exception conditions by returning a Check Condition status on the next SCSI command excluding Inquiry and Request Sense after an informational exception condition was detected The sense key shall be set to UNIT ATTENTION and the additional sense code shall indicate the cause of the information exception condition which is 5DOOh for a Tape Alert event The command that has the Check Condition shall NOT be executed before the informational exception condition is reported and thus needs to be repeated 0x3 Conditionally generate Recovered Error This method instructs the tape
103. d in the remainder of the descriptor Values are code DDS3 25h DDS4 26h DAT 72 47h Secondary 1 This is the same as Primary density code there are no secondary density densities supported for any media recognized by the drive code WRTOK 2 7 When 1 indicates that this density code is valid for both read and write When 0 indicates that this density code is valid for read only DUP 2 6 This will always return 0 indicating no duplicate density support data blocks for this code DEFLT 2 5 One indicates this density code is a default for the drive Note that since the drive density depends upon the cassette mounted all density codes are a default for the drive thus this field will always be one Page 130 Field Name Bits per MM Media width Tracks Capacity Assigning organization Density name Description Completion Status Bytes 5 7 8 9 10 11 12 15 16 23 24 31 32 51 Bits DDS 4 SCSI Interface Manual Rev B Description Bits per millimeter per track Value depends on density code DDS3 DDS4 12C0h DAT 72 1838h Media width in tenths of millimeters Specification width is 3 8 mm this value is 26h Tracks on a helical scan drive are defined as 1 The capacity is in megabytes and the value correlates with the primary density code as follows 25h 2bEEOh 26h 4E20h 47h 8CAOh This field contains the ASCII text Seagate padded with blanks Density name is ASCII data whi
104. d is set to 08h to indicate a medium changer device if the drive is an Autoloader and the LUN 1 Value 7Fh indicates that a logical unit is not present This value is returned in the case where an invalid LUN was contained in the last Identify message sent by the Initiator ANSI Version 2 0 2 This field contains 2 in compliance with ANSI standard SCSI 2 The field may contain 3 for drives that are ANSI 2 3 compliant Additional Length 4 This field indicates that 31 bytes of additional INQUIRY command parameters follow beginning in Byte 05h This value is not changed if the Allocation Length in the CDB is too small or too large to accommodate the entire response Addr16 6 0 The Addr16 field contains 1 indicating that the device supports 16 bit wide SCSI addresses SCSI 3 Vendor 8 15 This field contains 8 bytes of ASCII data SEAGATE followed Identification by 1 space Product Name 16 27 This field contains 12 bytes of ASCII data DAT followed by four spaces followed by DAT72 Product Revision 28 31 This field contains 4 bytes of ASCII data xxx the xxx is the Level 3 digit firmware revision part number for example 001 Firmware Version 32 35 This field contains the firmware version Note See product manual xxxxxxxxxxxx for details of alternate Inquiry data for Vendor ID and Product Name Commands Inquiry 12h Page 43 The VPD pages supported are as follows Byte co 1 Oo O1 COo o O
105. d the buffer is empty e When spacing locating or generally performing any tape motion when data cannot be transferred on the SCSI bus During the time the Target is disconnected for one of these functions the bus is free for use by other devices Both disconnect and reconnect are initiated by the Target When the Initiator first selects the drive it sends an Identify Message indicating that it is allowing the drive to disconnect and reconnect and to be capable of supporting messages other than Command Complete and the host set its own ID during selection To disconnect from the bus the DAT drive performs the following procedure 1 The drive can send a Save Data Pointers Message if the disconnection function was a data transfer 2 The drive sends a Disconnect Message indicating it is going to disconnect 3 The drive disconnects from the bus by de asserting BSY and releasing control of all bus signals The bus is now free for an Initiator to select any device on the bus including the drive that initiated the disconnect The drive will respond to selection by another Initiator If the DAT drive is selected while disconnected it only allows the following actions e fthe command is from a different initiator or is from the same initiator but to a different LUN the DAT drive accepts the command and immediately returns Busy Status e Immediately following the selection the Initiator may send the Identify No Op Abort or Bu
106. drive If Page Code is 0 only the 4 byte header and 8 byte block descriptor are returned Hex Page Name 00 No page returned 02 Disconnect Reconnect 0A Control Mode OF Data Compression Control 10 Device Configuration 11 Medium Partition 1C Tape Alert 1D Element address assignment Autoloader only 1F Device Capabilities Autoloader only 3F All available pages The Allocation Length field specifies the number of bytes the host has allocated for returned MODE SENSE data An Allocation Length of 0 00h means that no parameter list data bytes are returned to the host This condition is not considered an error The drive terminates the Data In phase in one of two ways based on whichever is less When Allocation Length bytes have been transferred When all available data have been transferred to the initiator Commands Mode Sense 1 Ah Page 91 MODE SENSE Parameters The parameter list for the MODE SENSE command contains e A four byte header followed by e Zero or one eight byte Block Descriptor followed by e Zero or more variable length pages The following table illustrates the structure of the Mode Sense command Bits Byte 7 6 5 4 3 2 1 0 0 z Parameter List Header 3 4 S Block Descriptor 11 12 Mode Pages The MODE SENSE response data consists of a four byte header followed by an eight byte block descriptor The following table shows the header format Bits Byte 7 6 5 4 3 2 1 0 0 Mode Sen
107. e 02h The Disconnect Reconnect page allows the host to tune performance of the SCSI bus The following table illustrates this page Bits Byte 7 6 5 4 3 2 1 0 0 0 0 Page Code 02h 1 Page Length OEh 2 0 0 0 0 0 0 0 0 3 0 0 0 0 0 0 0 0 4 0 0 0 0 0 0 0 0 5 0 0 0 0 0 0 0 0 6 0 0 0 0 0 0 0 0 7 0 0 0 0 0 0 0 0 8 0 0 0 0 0 0 0 0 9 0 0 0 0 0 0 0 0 10 MSB Maximum Burst Size 11 Maximum Burst Size LSB 12 0 0 0 0 0 0 DTDC 13 0 0 0 0 0 0 0 0 14 0 0 0 0 0 0 0 0 15 0 0 0 0 0 0 0 0 Disconnect Reconnect Page Field Descriptions The following table describes the fields in the Disconnect Reconnect page Field Name Page Code Page Length Maximum Burst Size Data Transfer Disconnect Control DTDC Bytes Bits 0 0 5 1 10 11 12 0 1 Description The Page Code field must be set to 02h to select this page The Page Length field must be set to 14 OEh which indicates that 14 parameter bytes follow the Page Length byte The Maximum Burst Size field specifies the maximum amount of data the drive can transfer during a Data phase before disconnecting if the initiator granted the disconnect privilege This value is in increments of 512 bytes That is a value of one means 512 bytes a value of two means 1024 bytes and so forth The Data Transfer Disconnect Control DTDC field values are as follows 00 Data transfer disconnect control is not used 01 The target does not attempt to disconnect once the data trans
108. e transferred with each REQ ACK handshake The default data transfer mode is asynchronous Synchronous data transfer operations are initiated through the SYNCHRONOUS DATA TRANSFER REQUEST message from the Initiator The SCSI bus protocol is divided into three modes or phases of operation Waiting Phases Control Phases and Information Transfer Phases These phases are further subdivided into the eight operational phases as listed in the following table Information on these operational phases is contained in the following paragraphs Waiting Phases Control Phases Information Phases 1 Bus Free 2 Arbitration 5 Command 3 Selection 6 Data Data In Data Out 4 Reselection 7 Status 8 Message Message In Message Out Waiting and Control Phases The status of the SCSI bus is a function of the control signals These signals define the SCSI as in the Waiting Phase Bus Free Phase the Control Phases Arbitration Selection or Reselection or the Information Transfer Phases Command Data Status or Message Seagate DDS 4 and DAT 72 drives support both a SCSI system with Arbitration Phase and a SCSI system without Arbitration Phase non arbitrating system Arbitrating Systems In arbitration systems required in SCSI 2 the sequence of SCSI bus phases follows the sequence shown in Figure 2 1 on the following page Operation begins with the Bus Free Phase Normal progression is from the Bus Free to the Arbitration Phase During A
109. e and detects an error on a message bytes an asserts ATN the drive e Switches the host to the Message Out Phase Waits for the host to send 09 Parity Error Message e Switches the host to the Message In Phase and resends the message Page 22 DDS 4 SCSI Interface Manual Rev B State or Phase Description Message Out If the host is in the Message Out Phase and sends a Phase message bytes and the drive detects a parity error the drive e attempts one retry then goes to Bus Free An Initiator that accommodates disconnect reconnect can indicate this capability to the DAT drive during the Selection phase by asserting both its own Initiator SCSI ID bit as well as the DAT SCSI ID bit allows the DAT drive to know with which Initiator to reconnect The Initiator must also assert ATN before exiting the Selection phase prior to releasing SEL and send an Identify message out of COh to the DAT drive This sequence causes the drive to enter the Message Out phase when the Selection phase completes The first message sent by the host after the Selection phase is an Identify message Under normal conditions the first message sent by the DAT drive after a Reselection phase is also Identify Under certain exceptional conditions the host may send the Abort message or the Bus Device Reset message instead of Identify as the first message SCSI Interface Description Page 23 SCSI Status Code Descriptions and Definitions The status
110. e cylinder error EF Tape reel error FO Tape mechanical error F1 Tape cut F2 Tape jam F3 Write append positioning error F4 Internal tape reader error F5 Tape audio format F6 Tape write append error F7 Tape is not initialized F8 Emergency eject F9 Internal tape process error FA Initialize failed FB Erase failure FC Invalid append AFC FD Missed tape interrupt FE Tape HC write failure FF Tape HC position not found 100 SCSI power on occurred 101 SCSI bus reset occurred 102 SCSI bus device reset function occurred 103 SCSI internal firmware reboot 104 SCSI transceivers changed to single ended 105 SCSI transceivers changed to LVD 106 Tape eject button aborted command Completion Status The Completion Status for the REQUEST SENSE command is shown in the following table Code Message Description 00h Good The drive is ready to perform any appropriate command Status The drive remains in any previously set mode The tape position is not changed 02h Check Extended Sense Byte 02h Condition Code Message Description 05h Illegal Request The CDB contains an invalid bit Page 146 DDS 4 SCSI Interface Manual Rev B RESERVE UNIT 16h 56h The RESERVE UNIT command reserves the drive for exclusive use of the requesting Initiator or for the exclusive use of third party specified SCSI device Note The 6 byte version of the RESERVE UNIT command uses opcode 16h the 10 byte version uses opcode 56h We re
111. e field is reserved and must be set to zero Command Descriptor Block Field Description The immediate IMMED bit byte 1 bit 0 can be used to specify that status be returned as soon as the operation is initiated When this bit is 1 the status is returned as soon as the rewind operation is initiated When this bit is 0 the status is not returned until the REWIND operation is completed Completion Status The Completion Status for the REWIND command is shown in the following table Code Message Description 00h Good The drive is ready to perform any appropriate command Status e The drive remains in any previously set mode The tape position is BOP if not IMMED 02h Check Extended Sense Byte 02h Condition Code Message Description 02h Not Ready No cartridge is inserted in the drive or the cartridge is being positioned to BOT 03h Medium Error See previous Exception Condition 04h Hardware Error Drive hardware failure detected 05h Illegal Request The CDB contains an invalid bit The Link bit and IMMED bit are both set to 1 06h Unit Cartridge was changed prior to accepting Attention this command The drive was reset prior to this command 08h Busy An immediate command is in progress Page 150 DDS 4 SCSI Interface Manual Rev B SEEK BLOCK 0Ch The SEEK BLOCK command is used to position the tape to the specified block address in the current partition No data is transferred SEEK BLOCK positions the t
112. eaning cartridge The tape drive has a hardware fault The drive has a hardware 1 Eject the tape or magazine fault that requires reset to 2 Reset the drive ER 3 Restart the operation The tape drive has a hardware fault The drive has a hardware 1 Turn the tape drive off and then on again fault that is not read write 2 Restart the operation related or requires a d power cycle to recover 3 If the problem persists call the tape drive supplier helpline Check the tape drive users manual for device specific instructions on turning the device power on and off Interface Eject Media Download Fail The tape drive has a problem with the host interface The drive has identified 1 Check the cables and cable connections an interfacing fault 2 Restart the operation The operation has failed Error recovery action 1 Eject the tape or magazine 2 Insert the tape or magazine again 3 Restart the operation The firmware download has failed because you have tried to use the Firmware download failed incorrect firmware for this tape drive Obtain the correct firmware and try again Page 68 DDS 4 SCSI Interface Manual Rev B The following table lists the flags supported by the autoloader The changer mechanism is having difficulty communicating with the Loader mechanism is tape drive having trouble 1 Turn the autoloader off then on communicating with the 2 Restart the operation tape drive 3 If problem
113. early warning condition The default setting is 0 If this bit is 1 the drive reports the early warning condition when the logical early warning position is encountered during read operations The drive reports early warning at completion of READ with no residual Not supported always 1 If set to 1 the Synchronize at Early Warning SEW bit causes the drive to flush all buffered write data to tape when the early warning position is encountered If set to 0 this bit indicates that encountering the early warning position will cause the buffer to flush The default setting is O A value of 0 indicates the data is not to be compressed a value of 1 indicates that the data is to be compressed using the default compression algorithm All other values are invalid Commands Mode Sense 1Ah Page 99 Medium Partition Page 11h The Medium Partition page indicates single or dual partition tape format the MODE SENSE command specifying a Medium Partition page can be executed at any logical position The tape does not need to be positioned at BOM The layout of this page is shown in the following table Bits Byte 7 6 5 4 3 2 1 0 0 0 0 Page Code 11h 1 Page Length 06h 2 Maximum Additional Partitions 3 Additional Partitions Defined 4 0 0 0 PSUM 0 0 0 5 0 0 0 0 0 0 1 1 6 0 0 0 0 0 0 0 0 7 0 0 0 0 0 0 0 0 8 MSB Additional Partition Size 9 Additional Partition Size LSB Medium Partition Page Field Descriptions T
114. ed separately for the two LUs For example if the loader contains a magazine but no cassette has yet been loaded into the drive then LUN 1 will be ready and LUN 0 will not Whenever the drive contains a cassette both LUs will be ready e Reset conditions affect the Autoloader as one unit A Bus Device Reset or SCSI Bus Reset initializes both LUN 0 and LUN 1 e An Unload command to LUN 0 ejects the cassette from the drive and stores it in the magazine slot in which it last resided If the Autoload feature is enabled the next cassette in sequence is then loaded An Unload command to LUN will return a cassette in the drive if any to its original magazine slot and will then eject the magazine e Following is a list of Request Sense sense key additional sense code qualifier values that are particular to the medium changer A complete list appears in the Request Sense command discussion in Chapter 3 Sense Code Title 05 21 01 Invalid Element Address 05 3B 0D Medium Destination Element Full 05 3B 0E Medium Source Element Empty 02 3A 00 Medium Not Present Reported if there is no magazine in the loader or if the magazine is empty and the drive contains no cassettes 06 28 00 Not Ready To Ready Transition Reported after magazine is inserted or if cassettes are loaded or changed by front panel command Cassette movement by SCSI command will not result in this condition Loading and Initialization The Scorpion 240 a
115. efinition of Sense Keys The following table shows the definition of the sense keys Key 00h Oth 02h 03h 04h 05h 06h 07h 08h OBh ODh OEh Message No Sense Recovered Error Not Ready Medium Error Hardware Error Illegal Request Unit Attention Data Protect Blank Check Aborted Command Volume Overflow Miscompare Definition The Check Condition occurred in conjunction with detection of FM EOT or ILI or status was not available The Log Sense counter reached its maximum value and the RLEC bit is set The drive is not ready to accept tape access commands Operator intervention may be required to correct this condition or the drive may be coming ready The command terminated with a non recoverable error that was probably caused by a flaw in the medium or an error in the recorded data The drive detected a non recoverable hardware failure parity etc while performing the command Until the cartridge is ejected or a reset is received the drive continues to return this sense key to any tape motion command The CDB or command parameters contained an illegal parameter One of the following actions occurred the cartridge was changed the drive was reset the operational mode was changed a Log Exception occurred or the firmware was changed The cartridge is write protected the operation was not performed A no data condition was encountered on the tape or the wrong d
116. eived e A hard reset condition occurs e The successful completion of the next SDTR message exchange If the Transfer Period is less than OAh or the REQ ACK Offset less than 4 the drive returns either a Transfer Period of zero or a REQ ACK Offset of zero to indicate the request cannot be supported in a synchronous manner and use of asynchronous transfer is requested If the host specifies a REQ ACK offset of zero the DAT drive operates in the asynchronous data transfer mode Command Phase During the Command Phase the Target requests command information from the Initiator The Target asserts the C D signal and de asserts the I O and MSG signals thus denoting the Command Phase The REQ ACK then handshakes the command bytes across the SCSI bus Figure 2 5 The command bytes are also called the Command Descriptor Block CDB SCSI Interface Description Page 15 Data Phase The Data Phase is subdivided into the Data In and Data Out Phases Data In Phase During the Data In phase the Target requests that data be sent to the Initiator from the Target The Target asserts the I O signal and de asserts the C D and MSG signals thus denoting the Data In Phase The REQ ACK handshakes Figure 2 4 then transfer the requested byte count Data Out Phase Status Phase Message Phase During a Data Out phase the Target requests that data be sent from the Initiator to the Target The Target de asserts the C D I O and MSG signals thus den
117. ense code qualifier is set to Threshold Condition Met 5B 01 If the counter is disabled because the DU bit is set 1 no threshold conditions are compared because the counter will not be incremented After the log exception is signaled by the Check Condition the host may issue the LOG SENSE command to determine which page and which counter by parameter code met the criteria or may read the sense key specific field in the REQUEST SENSE data The criteria for generating a Check Condition are specified by the TMC field in bits 2 and 3 of byte 2 of the parameter header The possible settings and resulting operation are as follows TMC Field Bits 3 2 Generate a Log Exception Check Condition 0 0 Whenever the accumulated value is incremented 0 1 When the accumulated value equals the threshold 1 0 Whenever the accumulated value does not equal the threshold 1 1 Whenever the accumulated value is greater than the threshold value This setting is the default value Commands Log Sense 4Dh Page 57 LOG SENSE 4Dh The LOG SELECT and LOG SENSE commands are used in conjunction with each other These commands allow the host to obtain and control statistical information This information consists of counts related to particular events that occur Some tabulated events page 3 refer to errors that have occurred since the Mini cartridge drive was powered on or last cleared by a LOG SELECT command and that have accumulated across seve
118. ensity Code field are as follows Code 25h DDS 3 format 26h DDS 4 format 47h DAT 72 NOTE Although the above values are approved by the ANSI X3T9 Technical Committee the values are not published in the SCSI 2 standard Block 5 7 This field indicates the size of a fixed length logical block Byte 5 is the Most Length Significant Byte MSB byte 7 is the Least Significant Byte LSB The default fixed block size for the drive is 512 bytes 200h Block Length may be set in a range from 1 to 224 1 bytes as specified in the READ BLOCK LIMITS command When this field is 0 the Block Length bytes indicate variable block mode Mode Page Format The following table shows the generic Mode Page format Bits Byte 7 6 5 4 3 2 1 0 0 0 0 Page Code 1 Page Length 2 Mode Parameters n The following table explains the page layout fields Field Name Bytes Description Page Code 0 The Page Code field identifies the format and parameters for this page as follows Hex Code Page Name 02 Disconnect reconnect 0A Control mode OF Data Compression Control 10 Device configuration 11 Medium partition 1D Element Address Assignment 1F Drive Capabilities Page 1 The Page Length field specifies the length in bytes of the mode parameters Length that follow the Page Length field Mode 2 n The mode parameters are described in the following subsections Parameters Page 94 DDS 4 SCSI Interface Manual Rev B Disconnect Reconnect Pag
119. er the accumulated Parameter Control byte is affected The LOG SENSE data reflects the current setting of the control byte for the parameter The Parameter Control byte bits used by the drive are described in the following table Bit Name Bytes Bits Description Disable 2 7 When set 1 this bit indicates that the host does not want this Update DU counter to be updated Enable 2 4 When set 1 this bit enables the generation of a Check Threshold Condition when an accumulated counter is incremented and Comparison the new value meets the threshold criteria and MODE ETC SELECT SENSE Control Mode Page RLEC bit is set See the following heading Use of the TMC Field and the ETC Bit Threshold Met 2 3 2 This field indicates when a Check condition should be Criteria Field generated when the ETC bit is set and a counter is updated TMC and MODE SELECT SENSE Control Mode Page RLEC bit is set See the following heading Use of the TMC Field and the ETC Bit The Parameter Length byte is the byte count of the parameter value that is being sent This length must be equal to the length returned by the LOG SENSE command The Parameter Value bytes indicate the value of the selected parameter type indicated in the CDB Parameter Code field The initiator must select either the accumulated or threshold values by the PC bits of the LOG SELECT CDB to send Parameter Value bytes USE OF THE TMC FIELD AND THE ETC BIT The Threshold Met Cri
120. er Control byte of the log data and the RLEC bit of the Mode Select Sense Control Mode page to determine if and when a log exception Check Condition should be generated when an accumulated count is incremented MAXIMUM COUNTS Threshold values are not the same as the maximum count The maximum size of each counter is according to the size of the counter in bytes When the maximum count is reached the DU bit in the Parameter Control byte for the counter is set to 1 for the Log Sense data indicating that the parameter is no longer to be updated because the maximum count has been reached When a counter reaches the maximum the counter is no longer incremented If a maximum value for the parameter size is reached the count does NOT roll over and continue counting When any counter of a page reaches maximum all counters of that page are no longer incremented A LOG SELECT command can be issued with the PC bits specifying default accumulated values to reset the accumulated values and to allow counters to continue as normal The DU bit of the affected parameter is also reset to zero LOG SELECT Parameter Data The host should issue a LOG SENSE command to initialize host software that allows Commands Log Select 4Ch Page 53 e Correct determination of the pages the drive uses e Determination of the parameter codes and length of each parameter The drive does not maintain a separate set of log parameters for each initiator Therefore a
121. eral versions and a number of individual documents The original Small Computer System Interface Standard X3 131 1986 is referred to herein as SCSI 1 SCSI 1 was revised resulting in the Small Computer System Interface 2 X3 131 1994 referred to herein as SCSI 2 The set of SCSI 3 standards are collectively referred to as SCSI 3 The applicable SCSI 3 standards are as follows SCSI 3 Architecture Model SAM X3 270 1996 SCSI Architecture Model 2 SAM 2 INCITS 366 2003 SCSI Parallel Interface 2 SPI 2 X3 302 1998 SCSI Parallel Interface 3 SPI 3 NCITS 336 2000 SCSI 3 Primary Commands SPC X3 301 1997 SCSI Primary Commands 2 SPC 2 NCITS 351 2001 SCSI 3 Medium Changer Commands SMC NCITS 314 1998 SCSI 3 Stream Commands SSC NCITS 335 2000 The term SCSI is used wherever it is not necessary to distinguish between the versions of SCSI Page 6 DDS 4 SCSI Interface Manual Rev B Commands Erase Read Position Exchange Medium Release Unit Initialize Element Status Receive Diagnostic Results Inquiry Report Density Support Load Unload Request Block Address Locate Request Sense Log Select Reserve Unit Log Sense Rewind Mode Select Seek Block Mode Sense Send Diagnostic Move Medium Space Prevent Allow Media Removal Test Unit Ready Read Verify Read Block Limits Write Read Data Buffer Write Data Buffer Read Element Status Write Filemarks Autoloader only commands Messages Abort Bus Device Reset Disconnect
122. error 4 40 AE Diagnostic DMA write data compare error 4 40 AF Diagnostic DMA read interrupt failed 4 40 BO Diagnostic DMA read FIFO overrun 4 40 B1 Diagnostic DMA read offset error 4 40 B2 Diagnostic DMA read HI parity error 4 40 B3 Diagnostic DMA read RD parity error Page 138 DDS 4 SCSI Interface Manual Rev B Byte 2 Sense Byte 12 Byte 13 Definition Key ASC ASCQ Additional sense code 4 40 B4 Diagnostic DMA read micro port access error 4 40 B5 Diagnostic DMA read counter error 4 40 B6 Diagnostic DMA read data compare error 4 40 B7 Invalid SANCHO revision 4 40 B8 Diagnostic task status unknown 4 40 B9 Diagnostic cable problems 4 40 BA Diagnostic excessive reset conditions 4 40 BB Diagnostic AIC in reset mode 4 40 BC Diagnostic micro port access not cleared 4 40 BD Diagnostic task timeout 4 40 BE Diagnostic Flash test failure 4 40 BF Diagnostic SDRAM test failure 4 40 CO Diagnostic EEPROM test failure 4 40 C1 Diagnostic Cronus SRAM test failure 4 40 C2 Diagnostic Kukai DRAM test failure 4 40 C3 Diagnostic Cronus SRAM test failure 4 40 C4 Diagnostic Cronus RW pass through failure 4 40 C5 Diagnostic Cronus RW compression failure 4 44 00 Internal failure 4 44 AD Capstan servo error 4 44 AE Tape cylinder error 4 44 AF Tape reel error 4 44 B4 Internal tape process error 4 44 B7 Internal error invalid tape status 4 44 B9 Internal error drive error 4 44 BA Internal error
123. error Unknown status returned to DC task from low level function DC Command reference queue error Compression hardware error DC space encounter file mark DC space encounter set mark DC space encounter end of partition DC space encounter beginning of partition DC space position lost DC space internal error DC invalid command state DC dictionary SRAM failed DC R W pass through failed DC R W compression failed DC detected group out of sequence Loader No Magazine Loader Invalid Source Address Loader Invalid Destination Address Loader Source Empty Loader Destination Full Loader Elevator Full Loader Not Present Loader Command Invalid Loader DTE Initialize Timeout Loader Busy Loader Insert cassette to drive failed Loader Insert magazine failed Loader Scan Failed Loader Diagnostic Failed Loader Extract cassette from drive failed Loader Extract cassette magazine failed Loader Command Timeout Loader General Failure Loader Magazine Present Loader Initialization Failed Loader Raise Elevator Failed Loader Lower Elevator Failed Loader Rotate Magazine Failed Page 144 DDS 4 SCSI Interface Manual Rev B Bytes 16 17 Definition vendor unique SKSV codes B7 Loader Load Magazine Failed B8 Loader Unload Magazine Failed B9 Loader Open Door Failed BA Loader Close Door Failed BB Loader invalid element address BC Loader invalid initialization parameter BD Loader invalid message param
124. es the partition to select partition O 00h or partition 1 01h This selection should agree with the current tape format either single partition or two partition Partition 1 is the first physical partition on a dual partition tape Page 48 DDS 4 SCSI Interface Manual Rev B LOCATE and the BT Bit Assume that the data was written on the tape as shown in the following table FRI cec EE E per es cus quor gore EE ES Bor T p we ipe pee pe per gps E e p ops ES EE B C D Position A If the Block Address Type BT bit is set in the CDB when the LOCATE command is issued all the setmarks and or filemarks are logically grouped with its nearest Data Block on its BOT side to form one logical block The following table shows the logical blocks when the BT bit is set In the table the data block block number 0 and five setmarks block numbers 1 5 are grouped together to form one logical block the filemark in block number 9 would be grouped with the data block block number 8 to form another logical block If the BT bit is 0 in the CDB when the LOCATE command is issued then each filemark and setmark on the tape is counted like the logical block while searching the target See the table that follows Bock o t 2 3 4 5 je 7 sa e fio t fiz 13 Bor Ip s Js s js js o jb b jr jo jp b Leon Referring to the first table the table below shows the tape position after each LOCATE command is complete L
125. ete messages as determined by the Flag bit Refer to description of Flag bit above Together group code and command code make up the op code If the Link bit is used all applicable commands must have the Immediate bit set to zero or a Check Condition status is returned and Extended Sense Key is set to Illegal Request Logical Unit Support The Seagate DDS 4 and DAT 72 drive only supports Logical Unit LUN 0 except for the Autoloader which supports both LUN 0 and LUN 1 However it responds to a host command that tries to select or identify any other LUN The response of the drive to illegal LUNs varies depending on the command and the manner in which the host specifies the LUN The host can specify an LUN I only by sending an Identify message after the Selection Phase Because of the redundancy of specifying the LUN the Seagate DDS 4 and DAT 72 drive responds appropriately if the LUN is specified in both the Identify message and in the CDB If the drive is selected and a valid Identify message is received with LUN 0 or LUN 1 if the drive is an Autoloader the LUN field of the CDB is ignored Thus the Identify message overrides the CDB LUN specification Because the SCSI INQUIRY command determines what LUNs a particular SCSI device supports the response from the drive to this command is unique With the INQUIRY command when the drive receives an unsupported LUN the command completes normally The drive indicates that it d
126. eter BE Loader flash changer bit not set BF Loader cassette lost CO RTOS status task ID error C1 RTOS status no memory available C2 RTOS status mailbox in use C3 RTOS status zero message C4 RTOS status invalid system call C5 RTOS status timeout C6 RTOS status no message present C7 RTOS status queue id error C8 RTOS status queue full C9 RTOS status partition id error CA RTOS status invalid configuration parameter CB RTOS status invalid input parameter CC RTOS status task pending on queue CD RTOS status event flag group and virtual timer id error CE RTOS status event flag already set CF RTOS status unknown error DO Hardware adjustment error D1 Tape path error D2 Unable to calibrate media D3 Non specific MCP error D4 Command reject error D5 Skip Device Area of media failed D6 PG error D8 High C1 errors during diagnostic D9 Cassette load count too high for diagnostic use DA EEPROM hardware error DB EEPROM disabled DC EEPROM not ready DD EEPROM received unknown command EO Internal tape writer error E1 Tape hit End of Data E2 Tape hit EOT E3 Tape hit BOT E4 Tape lost position E5 Tape position not found E6 Tape volume overflow E7 Tape write protected E8 Tape blank E9 Tape no cassette present EA Tape write failure Commands Request Sense 03h Page 145 Bytes 16 17 Definition vendor unique SKSV codes EB Tape cassette load error EC Tape cassette unload error ED Tape capstan error EE Tap
127. ev B Command Descriptor Block A request to a peripheral device is performed by sending a Command Descriptor Block CDB to the Target For several commands the request is accompanied by a list of parameters sent during a Data Out Phase If an invalid parameter is contained in the CDB the drive terminates the command without altering the medium The Seagate DDS 4 and DAT 72 drives implementation supports Group 0 and selected Group 1 and Group 2 commands Group 0 CDBs are six bytes Group 1 and 2 CDBs are ten bytes The CDB contains both reserved bit fields and defined bit fields Defined bit fields are Group Code Command Code Logical Unit Number LUN Vendor Unique VU Flag and Link whereas reserved bit fields are defined by zeros such as those appearing on the last line of the following table This table shows a typical Group 0 six byte Command Descriptor Block Note The LUN field must be 0 in the CDB Target LUN numbers are sent in the Identify Message Bits Byte 7 6 5 4 3 2 1 0 Group Code Command Code LUN Command Dependent Command Dependent Command Dependent Command Dependent VU VU 0 0 0 0 Flag Link O1 eo nm o The following table shows a typical Command Descriptor Block for Group 1 and 2 commands Bits 7 6 5 4 3 2 1 0 Group Code Command Code LUN Command Dependent Command Dependent Command Dependent Command Dependent Command Dependent Command Dependent Command Dependent Command Dependent VU VU 0
128. f contiguous bytes or blocks to be Length verified in fixed mode or the length of the variable block Data Blocks Verified Errors detected cause a Check Condition with the Sense Key set to 0E hexadecimal which indicates a data correction error The residual byte or block count is reflected in the REQUEST SENSE data When the Fixed bit is set 1 the Verify Length specifies the number of contiguous blocks to be verified on the tape When the Fixed bit is reset 0 the Verify Length specifies the number of bytes in the block to verify Commands Verify 13h Page 161 The byte compare starts on a block boundary starting at the current tape block position Completion Status The Completion Status for the VERIFY command is shown in the following table Code Message Description 00h Good e The drive is ready to perform any appropriate command Status e The drive remains in any previously set mode The tape is positioned on the EOT side of the last block verified 02h Check Extended Sense Byte 02h Condition Code Message Description 02h Not Ready No cartridge is inserted in the drive 03h Media Error Unrecoverable data error was encountered 04h Hardware Error Drive hardware failure detected 05h Illegal Request The CDB contains an invalid bit 06h Unit Cartridge was changed prior to accepting Attention this command The drive was reset prior to this command 08h Blank Check End of recorded data was encountered OEh
129. f the IMMED Immediate Bit is 1 status is to be returned as soon as the ERASE command is accepted and verified If the IMMED bit is 0 status is not returned until the tape is erased Long 1 0 If the Long bit is O or 1 a short ERASE is performed and EOD is recorded at the current tape position Completion Status The Completion Status for the ERASE command is shown in the following table Code Message Description 00h Good Status e The drive remains in any previously set modes The drive is ready to perform any appropriate command 02h Check Extended Sense Byte 02h Condition Code Message Description 02h Not Ready No cartridge is inserted in the drive 04h Hardware Error Parity error on SCSI bus or drive hardware failure detected 05h Illegal Request The CDB contains an invalid bit Both IMMED bit and Link bit are set to 1 06h Unit Attention Cartridge was changed prior to accepting this command Drive was reset prior to this command 07h Write Protect The cartridge in the drive is write protected Page 38 DDS 4 SCSI Interface Manual Rev B EXCHANGE MEDIUM AutoLoader Only A6h The EXCHANGE MEDIUM command provides a means to exchange the cartridge in the source element with the cartridge located in the drive This command provides the initiator a single command alternative to two MOVE MEDIUM commands when removing a cartridge from the DAT drive and inserting another cartridge into the DAT drive EXCHANGE MED
130. f this bit is 1 a block was read that has a length different than that which is specified This field indicates the status of the last command and provides a generic error category See Valid bit A number greater that zero in this field indicates that bytes 8 through N contain information This field provides further detail for the current Sense Key This field provides further detail for the current Additional Sense Code If the Sense Key Specific Valid SKSV bit is set 1 bytes 15 17 may be used to determine the first illegal parameter that caused an Illegal Request sense key as defined below If the Command Data C D bit is set 1 the illegal parameter is in the CDB Otherwise it is in the parameters sent in the Data Out Phase When the Bit Pointer Valid BPV bit is set 1 the Bit Pointer field indicates the bit field in error This field points to the most significant bit of the field in error Commands Request Sense 03h Page 135 Field Name Bytes Field Pointer 16 17 Bits Description If the BPV bit is set this field points to the most significant byte of the field in error Bytes are numbered starting from 0 When a Log Exception is generated bytes 16 and 17 indicate the MSB and LSB of the Log Parameter code that caused the Log Exception Byte 15 indicates the affected page that caused the Log Exception For all other errors this field may contain a Vendor Specific Code Qualifier D
131. fer of a command has been started until all data the command is to transfer has been completed 10 Reserved 11 The target does not attempt to disconnect once the data transfer of command has been started until the command is complete Commands Mode Sense 1 Ah Page 95 Control Mode Page 0Ah The Control Mode page allows the host to enable or disable the generation of a Check Condition when log parameters whose ETC bits are set to 1 meet their Threshold Condition Refer to the LOG SELECT command and the LOG SENSE command The layout of this page is shown in the following table Bits Byte 7 6 5 4 3 2 1 0 0 0 0 Page Code 0Ah 1 Page Length 06h 2 0 0 0 0 0 0 0 RLEC 3 0 0 0 0 0 0 0 DQUE 4 0 0 0 0 0 0 0 0 5 0 0 0 0 0 0 0 0 6 0 0 0 0 0 0 0 0 7 0 0 0 0 0 0 0 0 Control Mode Page Field Descriptions The following table describes the fields in the Control Mode page Field Name Bytes Description Page Code 0 The Page Code field must be set to OAh to select this page Page 1 The Page Length field must be set to six 06h which indicates that 6 Length parameter bytes follow the Page Length byte Report Log 2 A Report Log Exception Condition RLEC bit of 1 specifies that the target Exception reports log exception conditions A RLEC bit of 0 specifies that the target does Condition not report log exception conditions The default is 0 RLEC Tagged 3 The Tagged Queuing DQUE bit flag must be set 1 which specifies that Queuing
132. field specifies when Check Conditions are reported to the host when reading and the compressed format on the tape changes Only RED 0 is supported Other mode settings will be accepted but will function identically as RED 0 The Compression Algorithm byte allows the host to specify the algorithm that is to be used to compress data If the drive does not support the algorithm specified in the Compression Algorithm bytes a Check Condition is returned with the Sense Key set to Illegal Request The Decompression Algorithm byte allows the host to specify the algorithm that is to be used to decompress data If the drive does not support the algorithm specified in the Decompression Algorithm bytes a Check Condition is returned with the Sense Key set to Illegal Request The following table shows the DCE bit configuration and the supported algorithms An algorithm value of 01 which is the default can be used to determine the supported algorithm for the drive DCLZ 20 The value of 20 is returned by the corresponding MODE SENSE command DCE Algorithm Description XX 00 01 20 a 2 2 2 2 o 02 1F 21 FF Compression is disabled Compression is disabled Compression is enabled using the default algorithm DCLZ Illegal Request Compression is enabled using the DCLZ algorithm Illegal Request Device Configuration Page 10h The Device Configuration page specifies the appropriate sequential access device conf
133. fier is set to 26 02 06h Unit Cartridge was changed prior to accepting Attention this command The drive was reset prior to this command Commands Write Filemarks 10h Page 167 WRITE FILEMARKS 10h The WRITE FILEMARKS command causes the specified number of filemarks or setmarks to be written to tape This command can be used to force all remaining buffered data blocks to be written to tape without appending filemarks by specifying zero filemarks When zero filemarks are specified the command does not return Good Status to the Initiator until all buffered data blocks and filemarks are written correctly on the tape Otherwise status is returned immediately WRITE FILEMARKS Command Descriptor Block The following table shows the layout of the Command Descriptor Block Bits Byte 7 6 5 4 3 2 1 0 0 0 0 0 1 0 0 0 0 1 0 0 0 0 0 0 WSMK IMMED 2 MSB Number of Filemarks Setmarks 3 Number of Filemarks Setmarks 4 Number of Filemarks Setmarks LSB 5 vendor unique 0 0 0 0 Flag Link This vendor unique field is reserved and must be set to zero Command Descriptor Block Field Description The following table defines the fields in the CDB Field Name Bytes Bits Description WSMKbit 1 1 If this bit is 0 bytes 2 4 specify the number of filemarks to be written If this bit is 1 bytes 2 4 specify the number of setmarks to be written IMMED 1 0 If the IMMED bit is 1 status is returned as soon as the CDB has been va
134. g The DAT drive can write either fixed or variable block sizes The recording mode is determined by the Fixed bit in the SCSI WRITE and READ commands If the Fixed bit is set the MODE SELECT command sets the size of the next block or multiple blocks to be written with the next WRITE command When a WRITE command is issued with the Fixed bit set the current block size is implemented The transfer length specifies the number of blocks to be written with this size If a WRITE command is issued with the Fixed bit set and the current block size set to 0 the DAT drive returns a Check Condition with Illegal Request Sense Key When writing with the Fixed bit set each WRITE command specifies the number of contiguous blocks to be written of a fixed size resulting in fixed mode blocks If the Fixed bit is reset then only one block can be written on the tape per SCSI WRITE command CDB In that case the WRITE command CDB transfer length specifies the size of the block to be written in bytes With the Fixed bit reset the current block size specified with the last MODE SELECT command is ignored Setting the block size to 0 in the MODE SELECT page descriptor is not required Therefore with the Fixed bit reset each SCSI WRITE command may specify a different byte count resulting in variable mode blocks The host may switch between fixed and variable mode recording By issuing the MODE SELECT command to specify different block sizes blocks can be written t
135. g and the End of Partition If the Block Position Unknown bit is one the first and last block locations are not known or cannot be obtained If this bit is O the first and last block location fields contain valid position information This field reports the partition number for the current logical position Because the maximum number of partitions supported is two valid values for this bit are zero 00h and one 01h Partition 1 is the first partition on a dual partition tape These fields indicate the block address associated with the current logical position The value indicates the block address of the next data block to be transferred between the Initiator and the drive if a READ or WRITE command is issued Commands Read Position 34h Page 121 Last 8 11 These fields indicate the block address associated with the current Block logical position The value indicates the block address of the next data Location block to be transferred between the Initiator and the drive if a READ or WRITE command is issued Block 0 is the first block on each partition READ POSITION Data Format The following table shows the layout for the READ POSITION data format when the Long and TCLP bits are set to 1 Bits Byte 7 6 5 4 3 2 1 0 0 BOP EOP Reserved MPU BPU Reserved 1 Reserved 2 Reserved 3 Reserved 4 Partition Number MSB 0 5 Partition Number 0 6 Partition Number 0 7 Partition Number LSB 0 8 Block Number MSB
136. g the magazine can be performed only when there is a magazine in the drive To access the menu first eject the magazine if any and then press and hold the Select button until the menu appears on the LCD this will take about five seconds Then press the Select button momentarily to scroll among the menu items To choose one press the Enter button To return to the regular display momentarily press the Eject button Cassette Selection When the Select and Enter buttons on the Autoloader are used to select a cassette in the magazine it is loaded into the drive If there is already a cassette in the drive it will first be placed back in the slot from which it came If the drive is executing a SCSI command such as a Read or Write that and all pending commands will be terminated with Not Ready Operator Medium Removal Request 02 5A 01 status Automatic Loading Mode The front panel can be used to enable or disable automatic loading mode When enabled certain events cause the next cassette in the magazine to be loaded without either a SCSI or front panel command e Ejection of a cleaning cassette after a successful cleaning Cleaning failure due to an expired cleaning tape will not autoload the next tape e Ejection of a data cassette by a SCSI Unload command to LUN 0 e Insertion of a magazine After the magazine is scanned the first cassette will be loaded SCSI Interface Description Page 33 The following events will NE
137. han the originating requester including one that arrives from the third party currently in command of the drive is ignored and Good Status is returned in response to the command b Note The 6 byte version of the RELEASE UNIT command uses opcode 17h the 10 byte version uses opcode 57h We recommend using the 10 byte Release Unit Command since the older 6 byte command can only specify a Device ID in the range of 0 to 7 whereas the drive supports a Device ID in the range of 0 to 15 Additional events and conditions that can cause a reservation to be released are discussed under the RESERVE UNIT command b Note It is not an error to attempt to release an ID that is not currently reserved to the requesting Initiator A reservation cannot be released if another Initiator reserves it RELEASE UNIT Command Descriptor Block 6 byte version The following table shows the layout of the 6 byte CDB Bits Byte 7 6 5 4 3 2 1 0 0 0 0 0 1 0 1 1 1 0 0 0 3rd Pty 3rd Pty IDO 2 0 0 0 0 0 0 0 0 3 0 0 0 0 0 0 0 0 4 0 0 0 0 0 0 0 0 5 vendor unique 0 0 0 0 Flag Link This vendor unique field is reserved and must be set to zero The drive also supports the SCSI 3 10 byte Release Unit Command The table below shows the Descriptor Block for the 10 byte CDB b Note We recommend using the 10 byte Release Unit Command since the older 6 byte command can only specify a Device ID in the range of 0 to 7 whereas the drive supports a Device
138. handshake Initiator driven signal used to indicate an acknowledgment for a REQ ACK data transfer handshake Initiator driven signal used to indicate the Initiator has a message to communicate to the Target OR tied signal used to indicate a Reset condition Eight data bit signals plus a parity bit signal that form the odd bytes of the data bus DB 7 is the MSB and has the highest priority ID 7 during the Arbitration Phase Eight data bit signals that form the even byte of the data bus DB 15 is the MSB The data parity bit for the odd byte of the data bus Parity is odd and is a jumper selectable option Parity is not valid during the Arbitration Phase DB P is not to be driven False high during the Arbitration Phase Data parity bit for the even byte of the data bus NOTE The BSY and RST signals are the only OR tied signals In ordinary bus operation these signals may be simultaneously driven by two or more drivers There is no operational problem in mixing OR tied and three state drivers on signals other than BSY and RST Page 4 DDS 4 SCSI Interface Manual Rev B Command Set Description The following table shows the SCSI commands for sequential access devices implemented by the drive and autoloader Code Type Command Group 00h M TEST UNIT READY 0 Oth M REWIND 0 02h V REQUEST BLOCK ADDRESS 0 03h M REQUEST SENSE 0 05h M READ BLOCK LIMITS 0 07h A INITIALIZE ELEMENT STATUS 0 08h M READ 0 OAh M WRITE 0 OCh V SEEK
139. he drive was reset prior to this command Commands Mode Select 15h Page 73 MODE SELECT 15h The MODE SELECT command allows the host to assign device parameters After a power on or SCSI reset condition the drive sets its device parameters to the default values By issuing a MODE SELECT command the host can change the device parameters The parameters are transferred to the drive as data formatted in a parameter list Parameters assigned by the MODE SELECT command remain in effect until the drive receives a subsequent MODE SELECT command or a reset The MODE SELECT parameters are not unique to the initiator that assigned the parameters The MODE SELECT command immediately checks for invalid parameters or invalid combinations of parameters before executing If an exception is found the drive returns a Check Condition and the request sense data is set to Illegal Request You can issue a MODE SENSE command following a MODE SELECT command to determine which parameters if any were rounded to the nearest supported value MODE SELECT Command Descriptor Block The following table shows the layout of the CDB Bits Byte 7 6 5 4 3 2 1 0 0 0 0 0 1 0 1 0 1 ai KSE KSE GER CES EES GD 2 o o o 0o o0 o 0o Oo 3 0 0 0 0 0 0 0 0 4 Parameter List Length 5 vendor unique 0 0 0 0 Flag Link This vendor unique field is reserved and must be set to zero Page 74 DDS 4 SCSI Interface Manual Rev B Command Descr
140. he following table Code Message Description 00h Good Status Load 1 Load The tape is positioned to the BOT of the current partition The drive remains in any previously set modes The drive is ready to perform any appropriate command Load 0 The tape is position to BOT and ejected Unload The drive remains in any previously set modes The drive is ready to perform any appropriate command IMMER Good Status is returned once the command is transferred and verified The requested action may still be in progress when another command is issued Prior to returning status all buffered data is transferred to tape 02h Check Condition Extended Sense Byte 02h Code Message Description 02h Not Ready No cartridge is inserted in the drive 04h Hardware Error Parity error on SCSI bus or drive hardware failure detected 05h Illegal Request Both IMMED and Link bits are set to 1 The CDB contains an invalid bit 06h Unit Attention The cartridge was changed prior to BOT or at BOT following a LOAD command Commands Locate 2Bh Page 47 LOCATE 2Bh The LOCATE command is used to position the tape to the specified block address in the specified partition Before the locate operation is performed all buffered data filemarks and setmarks are transferred to tape On completion the logical position is before the specified location LOCATE Command Descriptor Block The following table shows the layout of the CDB
141. he following table describes the fields in the Medium Partition page Field Name Page Code Page Length Maximum Additional Partitions Additional Partitions Defined PSUM Additional Partition Size Bytes Bits 0 0 5 1 2 3 4 3 4 8 9 Description The Page Code field must be set to 11h to select this page If the current format is a single partition tape the Page Length byte is Set to 6 06h indicating that 6 parameter bytes follow the Page Length byte If the current format is a dual partition tape the Page Length is set to 8 08h indicating that eight parameter bytes follow the Page Length byte This field returns a 1 to indicate that at most only 1 additional partition can exist for a dual partitioned tape This field indicates the number of additional partitions on the current tape A zero specifies a single partitioned tape a one specifies a dual partitioned tape The Partition Size Unit of Measure PSUM field defines the units in which the partition size descriptors select the partition size The valid values are as follows The default is 10 megabytes 43 Unit 00 bytes 01 kilobytes 10 megabytes The Partition Size field defines the size of Partition 1 the first partition on a dual partition tape in the units specified in the PSUM field Byte 8 is the MSB and byte 9 is the LSB Page 100 DDS 4 SCSI Interface Manual Rev B Element Address Assignment Page Autoloader Only 1Dh
142. he total number of logical blocks from the beginning of the partition filemarks and setmarks are ignored and not counted in this mode Page 120 READ POSITION Data Format DDS 4 SCSI Interface Manual Rev B The following table shows the layout for the READ POSITION data format when the Long and TCLP bits are set to 0 Bits Byte 7 6 5 4 3 2 1 0 0 BOP EOP 1 1 0 BPU 0 1 Partition Number 2 0 0 0 0 0 0 0 0 3 0 0 0 0 0 0 0 0 4 MSB First Block Location 5 First Block Location 6 First Block Location 7 First Block Location LSB 8 MSB Last Block Location 9 Last Block Location 10 Last Block 11 Last Block Location LSB 12 0 0 0 0 0 0 0 0 13 0 0 0 0 0 0 0 0 14 0 0 0 0 0 0 0 0 15 0 0 0 0 0 0 0 0 16 0 0 0 0 0 0 0 0 17 0 0 0 0 0 0 0 0 18 0 0 0 0 0 0 0 0 19 0 0 0 0 0 0 0 0 READ POSITION Data Format Field Descriptions The following table lists the field descriptions Field Name BOP bit EOP bit BPU Partition Number First Block Location Bytes Bits 0 7 0 6 0 2 1 4 7 Description If the Beginning of Partition bit is 1 the current logical position is at the Beginning of Partition in the current partition If this bit is 0 the current logical position is not at the Beginning of Partition If the End of Partition bit is 1 the current logical position is between Early Warning and End of Partition in the current partition If this bit is O the current logical position is not between Early Warnin
143. host to enable or disable the generation of a Check Condition when log parameters whose ETC bits are set to 1 meet their Threshold Condition The layout of this page is shown in the following table Bits Byte 7 6 5 4 3 2 1 0 0 0 0 Page Code 0Ah 1 Page Length 06h 2 0 0 0 0 0 0 0 RLEC 3 0 0 0 0 0 0 0 DQUE 4 0 0 0 0 0 0 0 0 5 0 0 0 0 0 0 0 0 6 0 0 0 0 0 0 0 0 7 0 0 0 0 0 0 0 0 Commands Mode Select 15h Page 79 Control Mode Page Field Descriptions The following table describes the fields in the Control Mode page Field Name Bytes Page Code 0 Page 1 Length ReportLog 2 Exception Condition Disable 3 Queuing Bits 0 5 Description The Page Code field must be set to OAh to select this page The Page Length field must be set to 6 06h which indicates that 6 parameter bytes follow the Page Length byte A Report Log Exception Condition RLEC bit of 1 specifies that the target reports log exception conditions The Disable Queuing bit must be 1 to signify that tagged queuing is disabled Data Compression Control Page 0Fh The Data Compression DC Control page specifies whether or not data is compressed during a WRITE command and whether or not data is decompressed during a READ command It also provides for error reporting and selection of the compression algorithm The following table illustrates the DC Control page for drives with data compression Bits Byte 7 6 5 4 3 2 1 0 0 0 0 0 0 1 1
144. iguration The following table illustrates this page Byte Bits 7 6 Commands Mode Select 15h Page 81 0 0 0 Page Code 10h 1 Page Length OEh 2 0 CAP CAF DIS RAW EN C3 N Group 3 Active Partition 4 0 0 0 0 0 0 0 0 5 0 0 0 0 0 0 0 0 6 MSB Write Delay Time 7 Write Delay Time LSB 8 0 BIS RSMK 0 0 0 0 REW 9 0 0 0 0 0 0 0 0 10 0 0 0 EEG SEW 0 0 0 11 0 0 0 0 0 0 0 0 12 0 0 0 0 0 0 0 0 13 0 0 0 0 0 0 0 0 14 0 0 0 0 0 0 0 0 15 0 0 0 0 0 0 0 0 Page 82 DDS 4 SCSI Interface Manual Rev B Device Configuration Page Field Descriptions The following table describes the fields in the Device Configuration page Field Name Bytes Bits Page Code 0 0 5 Page il Length CAP bit 2 6 CAF bit 2 5 DIS RAW 2 4 EN C3 2 3 N Group 2 0 3 Active 3 Partition Write 6 7 Delay time BIS bit 8 6 RSMK bit 8 5 Description The Page Code field must be set to 10h to select this page The Page Length field must be set to 14 OEh which indicates that 14 parameter bytes follow the Page Length byte The CAP Change Active Partition bit is used to effect a partition change When the CAP bit is 1 the drive switches to the partition specified in the Active Partition field Once the MODE SELECT command completes the logical position is the BOP of the new partition If the CAP bit is 0 no partition change results The CAF Change Active Format bit is used to modify the tape format When the CAF bit is 1 bits 4 0
145. iled because the tape cartridge was manually Manual or forced eject ejected while the tape drive was actively writing or reading while drive actively writing or reading 17 Read Only W You have loaded a cartridge of a type that is read only in this drive Media loaded that is read Format The cartridge will appear as write protected only format 19 Nearing Media The tape cartridge is nearing the end of its calculated life It is Media may have Life recommended that you exceeded its specified 1 Use another tape cartridge for your next backup number of passes 2 Store this tape cartridge in a safe place in case you need to restore data from it Clean Now The tape drive needs cleaning The drive thinks it has a 1 If the operation has stopped eject the tape and clean the drive head clog or needs 2 If the operation has not stopped wait for it to finish and then cleaning clean the drive Check the tape drive users manual for device specific cleaning instructions Clean Periodic The tape drive is due for routine cleaning The drive is ready for a 1 Wait for the current operation to finish periodic clean 2 Then use a cleaning cartridge Check the tape drive users manual for device specific cleaning instructions Expired Cleaning Media The last cleaning cartridge used in the tape drive has worn out The cleaning tape has 1 Discard the worn out cleaning cartridge expired 2 Wait for the current operation to finish 3 Then use a new cl
146. ing table defines the fields in the CDB Field Name Bytes Bits Allocation 4 Length Description Set to 0 the default Transfer Length 3 is used When nonzero the number of bytes specified in the Allocation Length to a maximum of 3 bytes is transferred REQUEST BLOCK ADDRESS Address Data Format The following table provides the address data format Byte 0 1 2 Bits 7 6 4 3 2 MSp Block Address Block Address Block Address LSB Page 132 DDS 4 SCSI Interface Manual Rev B REQUEST BLOCK ADDRESS Address Data Field Description The Block Address Fields bytes 0 through 2 report the current tape position block number The first block on the tape is block number one Thus the Block Address returned will range from one to the maximum block currently written Completion Status The Completion Status for the REQUEST BLOCK ADDRESS command is shown in the following table Code Message Description 00h Good The drive is ready to perform any appropriate command Status e The drive remains in any previously set mode The tape position is not changed 02h Check Extended Sense Byte 02h Condition Code Message Description 04h Hardware Error Drive hardware failure detected 05h Illegal Request The CDB contains an invalid bit 06h Unit Cartridge was changed prior to accepting Attention this command The drive was reset prior to this command Commands Request Sense 03h Page 133 REQUES
147. iptor Block Field Description The following table defines the fields in the CDB Field Name Bytes Bits Description PF bit 1 4 The Page Format PF bit indicates whether the drive should interpret the MODE SELECT parameters that follow the CDB and the header as SCSI 1 or as SCSI 2 parameters For the Scorpion 40 drives the PF bit must be set to 1 SCSI 2 Parameter List 4 This field specifies the number of bytes in the MODE SELECT Length parameter list that are transferred from the host to the drive during a Data Out Phase A Parameter List Length of zero specifies that no data is to be transferred This length is valid and is not considered an error A length in this field that truncates a parameter list as returned ina MODE SENSE command causes the drive to return a Check Condition and the request sense data is set to Illegal Request MODE SELECT Parameters The parameter list for the MODE SELECT command contains e A four byte header followed by e Zero or one eight byte Block Descriptor followed by e Zero or more variable length pages The following table illustrates the structure of the mode select parameter list Bits Byte 7 6 5 4 3 2 1 0 0 Parameter List Header 3 4 Block Descriptor 11 12 Mode Pages The following table shows the Parameter List Header format Bits Byte 7 6 5 4 3 2 1 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 2 0 BUFFERED MODE 0 0 0 0 3 Block Descriptor Length Commands
148. ition 5 cct rtr ettet tates a recita e 112 Completion Gtaius eren enne enne nennen 113 READ DATA BUFFER SC a a eee nentes nnne tenens 114 READ DATA BUFFER Command Descriptor Block 114 Command Descriptor Block Field Description 114 READ DATA BUFFER Header AAA 115 READ DATA BUFFER Header Field Descriptions eeeeeeeeseeeeereeeenenrennnne 115 Contents Page vii Completion Status cae Len Oa E o REGE 115 READ ELEMENT STATUS Autoloader Only D 116 READ ELEMENT STATUS Command Descriptor Block 116 Element Status Data 116 Element Status Data Header 117 Gompletion Status ero aea m oL tas 120 READ POSGITION GA 121 READ POSITION Command Descriptor Block 121 READ POSITION Command Descriptor Block Field Descriptions 121 READ POSITION Data Fomat nennen 122 READ POSITION Data Format Field Descripitons sues 122 READ POSITION Data Format nennen 123 READ POSITION Data Format Field Descripitons sess 123 Completion EE 125 RECEIVE DIAGNOSTIC RESULTS 1Ch sss 126 RECEIVE DIAGNOSTIC RESULTS Command Descriptor Block 126 Command Descriptor Block Field Description 126 Completion Status 1 eret ade ett e Hee geltend KAES 127 RELEASE RUN 17h 57h iio ia iret ride ae 129 RELEASE UNIT Command Descriptor Block 129 Command Descriptor Block Field Description 130 Completion Status eit iei te tti rte T Reader tete pt eitis 13
149. its Byte 7 6 5 4 3 2 1 0 0 0 0 1 1 0 1 0 0 1 0 0 0 0 0 TCLP Long BT 2 0 0 0 0 0 0 0 0 3 0 0 0 0 0 0 0 0 4 0 0 0 0 0 0 0 0 5 0 0 0 0 0 0 0 0 6 0 0 0 0 0 0 0 0 7 0 0 0 0 0 0 0 0 8 0 0 0 0 0 0 0 0 9 vendor unique 0 0 0 0 Flag Link This vendor unique field is reserved and must be set to zero READ POSITION Command Descriptor Block Field Descriptions The following table lists field descriptions for the CDB Field Name Bytes Bits Description TCLP 1 2 1 The drive returns data specifying the partition file and set number with current logical position 0 The drive returns data specifying the first and last block location The Long bit and the TCLP bit must be equal otherwise the command shall be terminated with Check Condition status The sense key shall be set to Illegal Request and the additional sense code and an additional sense code qualifier set to Invalid Field in CDB Long 1 1 1 The drive shall return 32 bytes of data 0 The drive shall return 20 bytes of data The Long bit and the TCLP bit must be equal otherwise the command shall be terminated with Check Condition status The sense key shall be set to Illegal Request and the additional sense code and an additional sense code qualifier set to Invalid Field in CDB BT bit 1 0 If the BT bit is 0 the Block Location is the total number of logical blocks filemarks and setmarks from the beginning of the partition If the BT bit is 1 the Block Location is t
150. ive shall not report informational exception conditions more frequently than the specified timer interval and as soon as possible after the timer interval has elapsed A value of OxFFFFFFFF in the field indicates the timer interval is vendor specific and is a reserved setting in the Scorpion 40 drive Page 88 DDS 4 SCSI Interface Manual Rev B Completion Status The Completion Status for the MODE SELECT command is shown in the following table Code Message Description 00h Good Status The drive is ready to perform any appropriate command The defined mode is set and remains set until another MODE SELECT or RESET command is issued The tape position is not changed 02h Check Extended Sense Byte 02h Condition Code Message Description 02h Not Ready No cartridge is inserted in the drive 05h Illegal Request The CDB or Parameter List contains an invalid bit 06h Unit Cartridge was changed prior to accepting Attention this command or the drive was reset prior to this command The MODE SELECT command immediately checks the current page for invalid parameters or invalid combinations of parameters before executing If such an exception is found the drive returns a Check Condition status byte with an Illegal Request sense key If the initiator does not set the Page Length field of the Mode Page to the value indicated in the Mode Page definition for example OEh for the Device Configuration Page 01h for the Read Write Error Recove
151. ld does not identify the Initiator currently in control of the drive Page 148 DDS 4 SCSI Interface Manual Rev B Completion Status The Completion Status for the RESERVE UNIT command is shown in the following table Code Message Description 00h Good e The drive is ready to perform any appropriate command Status The drive remains in any previously set mode The drive is reserved for the use of the specified ID The tape position is not changed 02h Check Extended Sense Byte 02h Condition Code Message Description 04h Hardware Error Parity error on the SCSI bus or drive hardware failure detected 05h Illegal Request The CDB contains an invalid bit 06h Unit Cartridge was changed prior to accepting Attention this command The drive was reset prior to this command 18h Reservation The drive is reserved for another initiator Conflict Commands Rewind 01h Page 149 REWIND 01h The REWIND command causes the drive to rewind the cartridge to the Beginning of Partition BOP Any write data remaining in the buffer will be first recorded to the tape and an EOD marker will be recorded The REWIND operation is done in the high speed mode REWIND Command Descriptor Block The following table shows the layout of the CDB Bits Byte 7 6 5 4 3 2 1 0 0 0 0 0 0 0 0 0 1 1 0 0 0 0 0 0 0 IMMED 2 0 0 0 0 0 0 0 0 3 0 0 0 0 0 0 0 0 4 0 0 0 0 0 0 0 0 5 vendor unique 0 0 0 0 Flag Link This vendor uniqu
152. lems 4 Glanngrequred S The accuracy of the Enhanced Diagnostic is highly dependent upon the quality of the media used Use of new media is recommended To mitigate the possibility of worn out media being used the drive checks the load count written on the media If the load count is greater than 50 the diagnostic will terminate with a media error cartridge fault Completion Status The Completion Status for the RECEIVE DIAGNOSTIC RESULTS command is shown in the following table Code Message Description 00h Good The drive is ready to perform any appropriate command Status The drive remains in any previously set mode The tape position is not changed 02h Check Extended Sense Byte 02h Condition Code Message Description 04h Hardware Error Drive hardware failure detected 05h Illegal Request The CDB contains an invalid bit 06h Unit Cartridge was changed prior to accepting Attention this command The drive was reset prior to this command 04h Media A problem was encountered with the cassette Error Page 126 DDS 4 SCSI Interface Manual Rev B RELEASE UNIT 17h 57h The RELEASE UNIT command releases a current drive reservation if the command is received form the Initiator that originally established the reservation If the original reservation was made for a third party the RELEASE UNIT command Descriptor Block must also carry the third party data Any RELEASE UNIT command that arrives from other t
153. lidated Note IMMED of 1 is only valid if the drive is in buffered mode If the IMMED bit is O status is not returned until the write operation has completed and all buffered data written to the medium Number of 2 4 0 7 These fields specify the number of filemarks or setmarks to record Filemarks Setmarks Page 168 DDS 4 SCSI Interface Manual Rev B Completion Status The Completion Status for the WRITE FILEMARKS command is shown in the following table Code Message Description 00h Good e The filemarks have been sent to the buffer Status e The drive remains in any previously set mode 02h Check Extended Sense Byte 02h Condition Code Message Description 02h Not Ready No cartridge is inserted in the drive 03h Media Error Unrecoverable data error encountered Possibly bad cartridge 04h Hardware Error Drive hardware failure detected 05h Illegal Request The CDB contains an invalid bit 06h Unit Cartridge was changed prior to accepting Attention this command The drive was reset prior to this command 07h Write Protect The tape is write protected check the cartridge before continuing ODh Volume WRITE FILEMARK command completed with Overflow data in the buffer because the end of partition was encountered Commands Write Filemarks 10h Page 169 CERTANCE Certance LLC 1650 Sunflower Avenue Costa Mesa California 92626 USA Part Number 10010539 021 Printed in USA
154. liie t i te OR A RT tts 166 WRITE DATA BUFFER GD 168 Contents WRITE DATA BUFFER Command Descriptor Block 168 Command Descriptor Block Field Descriptions sess 169 WRITE DATA BUFFER Data Header 169 Gotmpletor talus etn tates te tss tat ets a dccem AE Lis 170 WRITE FIEEMARKS DD gege a Tutte dace He teda Aa 171 WRITE FILEMARKS Command Descriptor Block 171 Command Descriptor Block Field Description 171 Completion TEE 172 Introduction Page 1 Introduction 7 Overview The Seagate DDS 4 and DAT 72 DAT drives are designed for computer environments requiring high performance high capacity data storage These drives are available in 3 5 inch or 5 25 inch internal configurations or as an external subsystem The Autoloaders contain a DDS 4 or DAT 72 drive with an enclosure and tape manipulation mechanism Seagate DDS 4 and DAT 72 drives contain an embedded Small Computer Systems Interface SCSI controller These drives provide synchronous or asynchronous SCSI and a high speed burst synchronous data transfer rate of 80 Mbytes second The internal drive form factors are tailored for easy installation in today s computers and the full featured embedded SCSI controller facilitates easy integration into a variety of systems Drive Models This manual provides detailed information about the SCSI interface and SCSI commands that apply to Seagate DDS 4 and DAT 72 tape drives and autoloaders These drive
155. mand Descriptor Block Field Descriptions The command descriptor block fields are described in the following table Field Name Byte Bits Description Group Code 0 5 7 This field indicates the SCSI command groups used Command Code 0 0 4 This field indicates which of 32 command codes is sent NOTE The Group Code and Command Code are used together to indicate the operation code Logical Unit 1 5 7 The LUN must be set to zero Command 1 0 4 See specific command Dependent 2 4 0 7 Vendor Unique 5 6 7 These bits are reserved In the following command sections these bits are shown by Xs Flag and Link bits 5 0 1 These bits are used by all commands and described in the following subsection Flag and Link Bit Descriptions Flag and Link Bit Descriptions The Link bit enables a chain of commands to execute sequentially without the initiator reselecting the target By setting the Link bit the Initiator desires an automatic link to the next command on successful completion of the current command The Flag bit allows the initiator to track milestones in the linked command process by requesting a linked Command Complete with flag message from the drive If the CDB has the Link bit set the drive completes the command and takes the following actions 1 Goes to the Status phase and posts Intermediate Good status 2 Goes to the Message In phase and posts one of two possible messages according to the setting of the Flag bit 3 Pro
156. mmand uninitialized 72 Queue Element Pool sc Queue Element uninitialized 738 Failed to get free element from queue 74 Failed to free element during dequeue 75 Unknown Tape Status message 76 RB logical error Invalid sequence or state 77 RB function parameter value was invalid 78 Illegal value in the descriptor validation word 79 Placing RB descriptor failed 7A Getting RB descriptor failed 7B Writing data to the RB failed 7C Reading data from the RB failed 7D Unexpected value in Log Page Hook s Task Counter 7E Unknown log info response 7F Unknown log info response data pointer 80 Unrecognized message received from SCSI 81 Cassette has not been initialized 82 Overlapped command received from SCSI 83 DC hit End of Data 84 Invalid entity header length 85 Invalid entity reserved field Commands Request Sense 03h Bytes 16 17 86 87 88 89 8A 8B 8C 8D 8E 8F 90 91 92 93 94 95 96 97 98 99 9A 9B 9C 9D 9E 9F A0 A1 A2 A3 A4 A5 A6 A7 A8 A9 AA AB AC AD AE AF BO B1 B2 B3 B4 B5 B6 Page 143 Definition vendor unique SKSV codes Invalid entity compression algorithm Invalid entity record length field Invalid entity record count field Group buffer configuration error Host buffer configuration error Invalid ring buffer descriptor Invalid BAT entry Invalid BAT sequence found Invalid cassette data format ID Transfer skip BAT entry missing Unrecoverable ECC error Encountered a DCLZ
157. n when the tape was recorded The total correctable ECC error count is incremented each time the ECC process corrects one to two erroneous tracks read from the tape For performance reasons the ECC process corrects errors rather than retrying if the tracks in error are less than three otherwise a reread is performed Note This count is a count of the correctable C3 errors ONLY It does NOT include the C1 or C2 ECC errors normally encountered while reading DDS formatted cassettes The total bytes read count is incremented by the size of each group in bytes that is successfully read from the tape This count includes overhead bytes as defined by the DDS format specification that were read from the group However this count does NOT include any additional rewritten frames that were read nor any rereads Also it is greater than the count of read data bytes transferred The total uncorrectable errors count is a tabulation of the times the drive could not correct a read error by any means including the reread retry limit being exceeded The rereads since last write type operation count is similar to the total reread count 0002 except the counter is set to 0 in two cases e When the operation is changed to a write type operation e When a rewind operation is performed Tape Alert Log Page page 2Eh The Tape Alert Log page provides information about errors and status of the drive and media in the form of a flag for the supporte
158. n the host as a result of a connect or reconnect Current Data Pointers Current data pointers also known as Active Pointers are used to represent the state of the interface and point to the next Command Status or Data byte to be transferred between the memory of the Initiator and the Target Each Initiator may have only one set of Current Pointers The Current Pointers are used by the Target currently connected to the Initiator Saved Data Pointers Whether or not a currently active device is currently connected it has one set of Saved Data Pointers This set includes Command Status and Data Pointers that point to the Command Descriptor Block Status Area and Data Area respectively for that device The Saved Pointer continues to point to the start of the Data Area until the Target reconnects to the Initiator In response to the implied Save Data Pointer message the Initiator replaces the Current active Data Pointer with the value of the Saved Data Pointer Early Warning Function Early Warning on the DAT drive is a logical warning given when ten megabytes of storage space remain on the tape The position is calculated by the drive When this physical position is reached on a tape the following occurs 1 Data transfers from the host are terminated at the next block boundary 2 All data remaining in the drive buffer is written to the tape if the Synchronize at EW bit is set 3 The command completes with a Check Condition an
159. nd the cartridge is ejected without an error condition The UNLOAD command ejects the cartridge even if a PREVENT MEDIA REMOVAL command is in effect For the Autoloader an UNLOAD command ejects the cartridge from the drive into the storage element positioned in front of the drive and then inserts the next cartridge in sequence LOAD UNLOAD Command Descriptor Block The following table shows the layout of the CDB Bits Byte 7 6 5 4 3 2 1 0 0 0 0 0 1 1 0 1 1 1 0 0 0 0 0 0 0 IMMED 2 0 0 0 0 0 0 0 0 3 0 0 0 0 0 0 0 0 4 0 0 0 0 0 0 RT LOAD 5 vendor unique 0 0 0 0 Flag Link This vendor unique field is reserved and must be set to zero Command Descriptor Block Field Description The following table defines the fields in the CDB Field Name Bytes Bits Description IMMED 1 0 If the IMMED bit is 1 status is returned as soon as the operation is bit initiated If the IMMED bit is 0 status is not returned until the tape is positioned RT bit 4 1 Retension bit No retension is necessary for DDS DAT cartridges For Software compatibility this field can be either O or 1 LOAD 4 0 If the LOAD bit is 1 the tape moves to BOT bit If the LOAD bit is 0 the tape repositions to BOT The tape is then ejected Following an UNLOAD the drive accepts and executes any valid non media access commands Page 46 DDS 4 SCSI Interface Manual Rev B Completion Status The Completion Status for the LOAD UNLOAD command is shown in t
160. nformational exception condition was detected The sense key shall be set to NO SENSE and the additional sense code shall indicate the cause of the information exception condition which is 5DOOh for a Tape Alert event The command that has the Check Condition shall complete without error before any exception condition may be reported and thus does NOT need to be repeated 0x6 Only report informational exception condition on request This method instructs tape drive to preserve information exception s information To find out about information exception conditions the application client polls the tape drive by issuing an unsolicited REQUEST SENSE command The sense key shall be set to NO SENSE and the additional sense code shall indicate the cause of the informational exception condition which is 5DOOh for a Tape Alert event In MRIE modes 1h to 6h the additional sense code of 5DOOh indicates that a Tape Alert event has occurred on the device and detailed information about this event is stored in the Tape Alert Log page Note that the MRIE modes do not affect the logging of events in the Tape Alert Log page Interval Timer Default set to 0 When this field is set to zero this indicates that the target shall only report the informational exception condition one time When this field is set to non zero the value indicates the period in 100 millisecond increments for reporting that an informational exception condition has occurred The dr
161. nique 0 0 0 0 Flag Link This vendor unique field is reserved and must be set to zero Command Descriptor Block Field Description If the prevent PRVNT bit byte 4 bit O is 1 the cartridge cannot be ejected using the front panel Eject button If the PRVNT bit is 0 the Eject button is enabled Completion Status The Completion Status for the PREVENT ALLOW MEDIA REMOVAL command is shown in the following table Code Message Description 00h Good Status The drive is ready to perform any appropriate command The drive remains in any previously set mode The tape position is not changed e f a PREVENT command was issued the amber drive LED is always ON The cartridge cannot be removed e f an ALLOW command was sent the drive LED is ON only when the tape is accessed The tape can be removed at BOT without setting Unit Attention Condition 02h Check Condition Extended Sense Byte 02h Code Message Description 04h Hardware Error Drive hardware failure detected 05h Illegal Request The CDB or Parameter List contains an invalid bit 06h Unit Cartridge was changed prior to Attention accepting this command The drive was reset prior to this command Commands Read 08h Page 105 READ 08h The READ command transfers one or more bytes or blocks from the drive to the Initiator beginning with the next logical block on tape READ Command Descriptor Block The following table shows the layout of the CDB
162. nit Cartridge was changed prior to accepting Attention this command The drive was reset prior to this command Page 128 DDS 4 SCSI Interface Manual Rev B REPORT DENSITY SUPPORT 44h The REPORT DENSITY SUPPORT command requests transfer of information regarding the supported densities for the logical unit to the host REPORT DENSITY SUPPORT Command Descriptor Block The following table shows the layout of the CDB for REPORT DENSITY SUPPORT Bits Byte 7 6 5 4 3 2 1 0 0 0 1 0 0 0 1 0 0 1 0 0 0 0 0 0 0 Media 2 0 0 0 0 0 0 0 0 3 0 0 0 0 0 0 0 0 4 0 0 0 0 0 0 0 0 5 0 0 0 0 0 0 0 0 6 0 0 0 0 0 0 0 0 7 Allocation Length 8 Allocation Length LSB 9 vendor unique 0 0 0 0 Flag Link This vendor unique field is reserved and must be set to zero Command Descriptor Block Field Description The following table defines the fields in the CDB for REPORT DENSITY SUPPORT Field Name Bytes Bits Media 1 0 Allocation 7 8 Length Description A Media bit of zero indicates that the drive will return density support data blocks of the densities supported by the logical unit for any supported media A Media bit of one indicates the drive will return density support blocks for the densities supported by the mounted media The Allocation Length specifies the maximum number of bytes that the drive may return Truncation will occur if the Allocation Length is less than the number of bytes in the requested density support d
163. nitiator when the operation is completed For example the status is returned when the tape has been repositioned An Immediate bit of one means that the status is returned to the Initiator as soon as the function is started Residual Length Function When performing a WRITE command the drive returns a Good Status and Command Completion Message when the last byte requested by the command is placed in the Data Buffer rather than when it is written onto tape If an error occurs while data is being written onto tape the drive calculates the Residual Length and places this value in the information bytes of the Sense Data Block Also the Residual Length functions for other commands such as READ and SPACE Residual Length is calculated by RL TL AL Where AL Actual Length Blocks transferred from the host to the DAT drive across the SCSI bus TL Transfer Length The Transfer Length from bytes 2 4 of the WRITE command Request Transfer Length RL Residual Length The amount of blocks or bytes not written to tape Page 26 DDS 4 SCSI Interface Manual Rev B Disconnect Reconnect Function When the drive is performing a task not requiring communication with the Initiator or when the DAT drive determines that a relatively long time has passed with no bus activity it disconnects from the SCSI bus Examples are e When rewinding the tape e When writing to the tape and the buffer is full e When reading from the tape an
164. nostic DMA write offset error Diagnostic DMA write host interface parity error Commands Request Sense 03h Bytes 16 17 1B 1C 1D 1E 1F 20 21 22 23 24 25 26 27 28 29 2A 2B 2C 2D 2E 32 33 34 35 36 37 38 39 3A 3B 3C 3D 42 43 44 45 46 47 48 49 4A 4B 4C 4D 4E 4F 50 51 52 Page 141 Definition vendor unique SKSV codes Diagnostic DMA write RD parity error Diagnostic DMA write micro port access error Diagnostic DMA write counter error Diagnostic DMA write data compare error Diagnostic DMA read interrupt failed Diagnostic DMA read FIFO overrun Diagnostic DMA read offset error Diagnostic DMA read HI parity error Diagnostic DMA read RD parity error Diagnostic DMA read micro port access error Diagnostic DMA read counter error Diagnostic DMA read data compare error Invalid SANCHO revision SCSI page out of range Diagnostic cable problems Diagnostic excessive reset conditions Diagnostic AIC in reset mode Diagnostic micro port access not cleared SCSI task revd kmsg with null info field PTR SCSI RB unknown descriptor type Loader cassette jamming on insertion Loader clamp failure Loader cassette arm failure SCSI impossible condition trap SCSI active cmd with null pCommanddone Diagnostic flash test failure Diagnostic SDRAM test failure Diagnostic EEPROM test failure Diagnostic Cronus SRAM test failure Diagnostic Kukai DRAM test failure SCSI FE dispatch null pointer SCSI BE dispatch
165. ns the maximum count that each parameter code can attain For example a two byte field returns two bytes of all 1s a three byte field returns three bytes of all 1s These default values cannot be changed by the LOG SELECT Page 60 DDS 4 SCSI Interface Manual Rev B command The default threshold values are loaded into the threshold values when a reset occurs or by a LOG SELECT command with the PCR bit set Default Accumulated Values The type 3 page control bit setting specifies default accumulated values The default accumulated values are all zero and cannot be changed by the LOG SELECT command The default accumulated values are loaded into the accumulated values when a reset occurs or when a LOG SELECT command is received with the PCR bit set Using the Parameter Pointer Field The Parameter Pointer field specifies the starting parameter code of the page that is to be transferred If the Parameter Pointer field specifies a parameter code larger than the maximum parameter code for that page a Check Condition is generated The sense data is set to Illegal Request Invalid Field in the CDB For example if the page uses parameter codes 2 through 6 and the parameter pointer field is set to 3 then the drive returns parameters 3 through 6 Likewise if the parameter pointer is set to 1 parameters 2 through 6 are returned If the Parameter Pointer field is set to 0 all parameters for that particular page are returned up to the maximum
166. nts in page 30 are similar to those in pages 2 and 3 the page 2 and 3 counts are incremented separately from those in page 30 The accumulated counts in pages 2 and 3 accumulate across cassettes after the counts are initialized by the LOG SELECT command or since the last reset or power cycle Thus the counts in those two pages can be used to accumulate events in a different way than the counts in the log sense page 30 If multiple log pages are sent they must be sent in ascending order All log parameters of a particular page must be sent to the drive in ascending order Not all parameter codes need to be sent with the parameter data during the Data Out phase In that way selected parameters of a particular page can be initialized to any value desired The following conditions constitute errors that cause the drive to return a Check Condition and to set sense data to Illegal Request Invalid Parameter Data Page 54 DDS 4 SCSI Interface Manual Rev B e If any page headers are received with unsupported page codes Table 4 30 lists the pages that can be set by the LOG SELECT command e An incorrect log page length is specified in the page header e Anillegal parameter code within a valid log page e Valid log pages are not sent in ascending order e Parameter codes of a supported page are not sent in ascending order The following table shows the log page header format Bits Byte 7 6 5 4 3 2 1 0 0 0 0 Page Code 1 0 0 0 0 0 0 0
167. nual Rev B Parameter List Block Descriptor Field Descriptions The following table defines the fields in the Parameter List block descriptor Field Name Bytes Description Density 0 The following values define this field Code Hex Code Meaning 00 Default format DDS 7F No op 25 DDS 3 26 DDS 4 47 DAT 72 The drive will accept any of these density codes as valid when sending a Block Descriptor The density code does not dictate the format written on the media the drive detects the media type and writes the correct format for that media Selecting a Density Code value not listed above or not supported by the drive will result in a Check Condition The sense data is set to Invalid field in parameter list Block 5 7 If this field is nonzero it indicates the length of the fixed length block to be read or Length written when the Fixed bit is set in a READ or WRITE command It is acceptable to set the Fixed bit to 0 The default is 512 byte blocks which may be changed at any time by the host with a MODE SELECT command If this field is zero variable length block mode is specified and the Fixed bit in the READ or WRITE command must be 0 The Block Length in a READ or WRITE command may be set in a range from 1 to 16 MB as specified in the READ BLOCK LIMITS command Mode Page Format The following table shows the generic Mode Page format Bits Byte 7 6 5 4 3 2 1 0 0 0 0 Page Code 1 Page Length 2 Mode Parameters
168. number of bytes specified in the allocation length Regardless of the starting parameter code specified in the Parameter Pointer field the page header is always returned Log Sense Pages Only one log page is transferred to the host with a single LOG SENSE CDB Byte 2 of the CDB specifies the page to be transferred Each log page begins with a four byte header as shown in the following table Bits Byte 7 6 5 4 3 2 1 0 0 0 0 Page Code 1 0 0 0 0 0 0 0 0 2 0 0 0 0 0 0 0 3 Page Length n The Page Code field indicates the page being returned This data matches the page code requested in byte 2 of the LOG SENSE CDB The Page Length field indicates the length of the page in bytes that follow the page header If the allocation length specified in the CDB is too small to transfer all of the requested page this value is not adjusted to reflect the truncation However if the Parameter Pointer field of the CDB specifies a starting parameter code other than zero the page length is adjusted to indicate the number of bytes that follow the page header Commands Log Sense 4Dh Page 61 The following subsections describe the log sense pages List of Available Pages Page 0 Page 0 indicates the log sense pages used by the drive To determine the size of each page and of each parameter in the page the individual pages must be requested Page 0 is unique in that the parameter data returned does not contain log parameter headers
169. o the tape with different block sizes in the fixed mode Also the host may change the block size after BOM allowing on the fly block size changes The READ command Fixed bit also specifies fixed or variable mode SCSI Interface Description Page 29 When reading in variable mode the host must know the size of the block to be read from the tape in advance in order to avoid causing the DAT drive to return a Check Condition with Incorrect Length indicated in the Sense data ILI Also the data transfer may be truncated cut off when the recorded block does not match the transfer length in variable mode or the current block size in fixed mode The SCSI 2 READ command includes a SILI bit to Suppress ILI Check conditions When the SILI bit is set the host usually specifies the maximum block size before reading so that the data blocks are not truncated and no Check Conditions are generated The SCSI READ BLOCK LIMITS command returns the minimum and maximum block sizes that the DAT drive can support The Block Limits data is not modified to reflect the current mode of writing fixed or variable The Block Limits returned data is not modified to reflect the current block size for the next fixed mode WRITE The MODE SENSE command is used for that purpose Autoloader Operation General SCSI Information The Scorpion 240 is in SCSI 3 terminology a tape drive with an independent medium changer SCSI Stream Device i e tape commands are addres
170. o obtain the information last written to the DDS Tape Log Each time the cartridge is ejected the Tape Log is updated This log contains two types of counts e The Previous counts indicate events from the previous usage cycle of the cassette A usage cycle is composed of a single cartridge insertion use and ejection e The Total counts accumulate events over the life of the cassette since the cassette was first initialized by a format process When a cartridge is formatted the total and previous counts are initialized to 0 The previous counts in this page are updated when a previously formatted cassette is inserted to indicate the counts from the previous usage of the tape The previous counts remain consistent through the usage cycle Previous counts can be inspected with the LOG SENSE command If no activity occurs during the usage cycle then the previous counts are all set to 0 and the Load Count is incremented by 1 Commands Log Sense 4Dh Page 69 When a previously used cartridge is inserted the total counts are updated to the values contained in the Tape Log of the inserted cassette The total counts can be read with the LOG SENSE command Also page 30 contains a set of current counts The current usage counts are not part of the Tape Log They are initialized to 0 when the cartridge is inserted While the tape is in use the current usage counts are incremented according to the DDS format definitions as an event occurs
171. o tape when the early warning position is encountered during writing Medium Partition Page 11h The Medium Partition page specifies the number and size of partitions to be created on the medium The layout of this page is shown in the following table MSB Additional Partition Size Bits Byte 7 5 4 3 2 1 0 0 0 Page Code 11h 1 Page Length 06h 2 Maximum Additional Partitions 3 Additional Partitions Defined 4 0 IDP PSUM 0 0 0 5 Medium Format Recognition 6 0 0 0 0 0 0 0 7 0 0 0 0 0 0 0 8 9 Additional Partition Size LSB Page 84 DDS 4 SCSI Interface Manual Rev B Medium Partition Page Field Descriptions The following table describes the fields in the Medium Partition page Field Name Page Code Page Length Maximum Additional Partitions Additional Partitions Defined SDP bit IDP bit PSUM Medium Format Recognition Additional Partition Size Bytes Bits 0 0 5 1 2 7 0 3 4 6 4 5 4 3 4 5 7 0 8 9 Description The Page Code field must be set to 11h to select this page If no additional partition is to be defined or if going from a dual partition format to a single partition format the Page Length field must be set to 6 06h which indicates that 6 parameter bytes follow the Page Length byte If an additional partition is to be defined dual partition this field is Set to 8 08h The Maximum Additional Partitions field indicates the maximum number of addi
172. ock N is always at the end of block N The following figure illustrates this position Current Block Size 512 bytes block Block N 1 Block N Block N N 1 512 bytes 514 bytes 512 bytes T T Encounter ILI Logical Position error reading after ILI error block N Fixed Mode Residual Data When the Fixed bit is set 1 the residual data is set to the CDB Transfer Length minus the actual number of blocks correctly read without encountering an ILI error For example assume the following e The current block size is 512 bytes block e The drive is currently positioned before block N e Block N contains 514 bytes If the host issues a READ command with a CDB Transfer Length of one indicating one 512 byte block is to be read the drive transfers the first 512 bytes of block N then skips the last two bytes 513 and 514 and reports a Check Condition caused by an Incorrect Length error The residual is set to one This residual is determined as follows CDB Transfer Length Number of blocks correctly read without encountering an ILI error 1 0 1 The logical position after the error is after byte 514 of block N Variable Mode Residual Data When the Fixed bit is reset 0 the residual data is always set to the CDB Transfer Length minus the actual block length Commands Read 08h Page 109 For example assume the following e The drive is currently positioned before block N e Block N 1 contains 512 bytes The
173. oes not support the specified LUN by returning a 7F hexadecimal value in byte 0 of the INQUIRY data Regardless of what method is used to specify the LUN the 7F hex value is returned If an unsupported LUN is specified for a REQUEST SENSE command the command completes normally with Good Status and the sense data is set to Illegal Request For all other commands the illegal LUN is detected in the Identify message If an illegal LUN is specified in the Identify message the drive enters the Command Phase and accepts the CDB It immediately skips to the Status Phase and posts a Check Condition The Sense data is set to Illegal Request If the Identify message is correct the CDB LUN is ignored Page 18 SCSI Message Descriptions and Definitions DDS 4 SCSI Interface Manual Rev B The SCSI message codes descriptions and directions are given in the following table Each of these SCSI messages is supported by the Seagate DDS 4 drive Code 00h 02h 03h 04h 05h 06h 07h 08h 0Ah OBh 0Ch 80h COh 01h Description Command Complete Save Data Pointer Restore data pointers Disconnect Initiator Detected Error Abort Message Reject No Operation Linked Command Complete Linked Command Complete with Flag Bus Device Reset Identify when sent by host disables Disconnect Reconnect Identify enable Disconnect Reconnect Extended Message Direction In Drive to host Out Host to drive Direction Out
174. of byte may be changed The DIS RAW Disable Read After Write bit enables and disables the read after write capability If the value is 1 read after write check and rewrites are disabled If the value is 0 read after write is enabled The EN C3 Enable C3 bit enables and disables C3 ECC code generation during writing If the value is 1 C3 ECC code is generated during writing if the value is 0 C3 ECC code is not generated The N Group field specifies the number of copies of each tape group to record Values greater than 0 can be used to increase reliability The Active Partition field is valid only when the CAP bit is 1 This field specifies the partition number of the new partition to which the drive switches when the MODE SELECT command completes The drive supports a maximum of two partitions The valid values for this field are O 00h and 1 01h Partition 1 is the first partition on a dual partition tape For a WRITE command the Write Delay Time field indicates to the drive how long in 100 millisecond increments to delay writing buffered data to tape after the last WRITE command Not supported must be set to 1 The Report Setmarks RSMK bit determines whether or not the drive recognizes setmarks If the value is 1 the drive recognizes and reports setmarks during appropriate read and space operations If the value is 0 the drive ignores setmarks It skips any setmark it finds during execution of read or space type command
175. on This field indicates the number of setmarks between beginning of medium and the current logical position All bits are O Commands Read Position 34h Page 123 Completion Status The Completion Status for the READ POSITION command is shown in the following table Code Message Description 00h Good e The drive is ready to perform any appropriate command Status e The drive remains in any previously set mode e The tape is not moved 02h Check Extended Sense Byte 02h Condition Code Message Description 02h Not Ready No cartridge is inserted in the drive 04h Hardware Error Parity error on the SCSI bus or drive hardware failure detected 05h Illegal Request The CDB contains an invalid bit 06h Unit Cartridge was changed prior to accepting Attention this command The drive was reset prior to this command Page 124 DDS 4 SCSI Interface Manual Rev B RECEIVE DIAGNOSTIC RESULTS 1Ch The RECEIVE DIAGNOSTIC RESULTS command requests any available analysis data is sent to the initiator after completion of aSEND DIAGNOSTIC command The drive does not use any of the optional diagnostic page data thus no data is returned with this command RECEIVE DIAGNOSTIC RESULTS Command Descriptor Block The following table shows the layout of the CDB Bits Byte 7 6 5 4 3 2 1 0 0 0 0 0 1 1 1 0 0 1 0 0 0 0 0 0 0 0 2 0 0 0 0 0 0 0 0 3 MSB Allocation Length 4 Allocation Length LSB 5 vendor unique 0 0 0 0 Fl
176. ost data is written to tape in the uncompressed DDS format This value is used for drives without data compression capabilities The DCC Data Compression Capable bit values are as follows 1 The drive is capable of doing compression 0 The drive cannot do compression NOTE This bit is ignored during MODE SELECT The DDE Data Decompression Enable bit contains the last value set by the host with a MODE SELECT command For either value the drive decompresses data that has been compressed on the tape before it sends the data to the host during a READ command The default value is 1 The default value is 0 The Compression Algorithm byte specifies the algorithm that is to be used to compress data with the DCE bit set to 1 A value of 20h in this byte specifies the DCLZ algorithm which is the default If the host selects a value of O1h for the default algorithm a value of 20h is returned by the MODE SENSE data The Decompression Algorithm byte allows the host to specify the algorithm that is to be used to decompress data The byte is valid whether or not the drive decompresses the data The byte defaults to a value of 20h to indicate DCLZ decompression The following table shows the algorithm values and meaning Algorithm 00 20 Definition The data last sent to the host was uncompressed The data last sent to the host was compressed using the DCLZ algorithm Commands Mode Sense 1 Ah Page 97 01 1F The data last sent
177. ot read medium incompatible format Page 140 DDS 4 SCSI Interface Manual Rev B Byte 2 Sense Byte 12 Byte 13 Definition Key ASC ASCQ Additional sense code B Aborted Command B 08 01 Logical unit communication time out B 1B 00 Synchronous data transfer error B 30 00 Invalid media B 3D 00 Invalid bits in identify message B 43 00 Message error B 45 00 Select or reselect error B 47 00 SCSI parity error B 48 00 Initiator detected error message received B 49 00 Invalid message error B 4A 00 Command phase error B 4B 00 Data phase error B 4E 00 Overlapped commands attempted B 53 00 Media load or eject failed B 5A 01 Operator medium removal requested D Volume Overflow D 00 02 End of partition medium detected Vendor Specific Code Qualifiers The following table lists the vendor unique SKSV codes referenced in the table above Bytes 16 17 Definition vendor unique SKSV codes Unexpected PC in Log Select Invalid log parameter Invalid log page Invalid Tape Alert Negative Tape Alert report count Unexpected Tape Alert MRIE Invalid log exception Invalid CDB length Log page 3C response failed Invalid EEPROM alert Invalid EEPROM response SCSI Diagnostic initialization failed Diagnostic SBIST failed Diagnostic BBIST failed Diagnostic DBIST failed Diagnostic DMA setup failed Diagnostic host interface RAM failed Diagnostic AIC RAM failed Diagnostic DMA write interrupt failed Diagnostic DMA write FIFO overrun Diag
178. oting the Data Out Phase The REQ ACK handshakes Figure 2 5 then transfer the requested byte count across the SCSI bus During a Status Phase the Target requests that status information be sent to the Initiator from the Target The Target asserts the C D and I O signals and de asserts the MSG signal thus denoting the Status Phase The REQ ACK handshakes the one byte status code across the SCSI bus refer to Figure 2 4 The Message Phase consists of either the Message In or Message Out Phases The Seagate DDS 4 and DAT 72 drive supports one byte messages Message In Phase During the Message In Phase the Target requests that messages be sent to the Initiator from the Target The Target asserts the C D I O MSG signals thus denoting the Message In Phase The REQ ACK handshakes the one byte message across the SCSI bus Message Out Phase During the Message Out Phase the Target requests that messages be sent from the Initiator to the Target The Target invokes this phase in response to the Attention ATTN signal asserted by the Initiator The drive responds to the ATTN signal at every phase change The Target asserts the C D and MSG signals and de asserts the I O signal denoting the Message Out Phase The REQ ACK handshakes the one byte message across the SCSI bus The Target uses REQ ACK handshakes Figure 2 5 until the ATN signal becomes false unless an error occurs and the message is rejected Page 16 DDS 4 SCSI Interface Manual R
179. persists call the tape drive supplier helpline Hardware A Loader Stray A tape has been left in the autoloader by a previous hardware fault Stray tape left in loader 1 Insert an empty magazine to clear the fault after previous error 2 If the fault does not clear turn the autoloader off and then on Tegovety again 3 If the problem persists call the tape drive supplier helpline There is a problem with the autoloader mechanism Loader mechanism has a hardware fault Hardware B The autoloader has a hardware fault The loader mechanism has 1 Turn the autoloader off and then on again a hardware fault that is not mechanically related Loader Hardware C 2 Restart the operation 3 If the problem persists call the tape drive supplier helpline Check the autoloader users manual for device specific instructions on turning the device power on and off Loader Magazine The autoloader cannot operate without the magazine Loader magazine not 1 Insert the magazine into the autoloader present 2 Restart the operation 43 Loader Door The operation has failed because the autoloader door is open Tape changer door open 1 Clear any obstructions from the autoloader door 2 Eject the magazine and then insert it again 3 If the fault does not clear turn the autoloader off and then on again 4 If the problem persists call the tape drive supplier helpline DDS Tape Log page 30 Page 30 the DDS Tape Log page allows you t
180. positioned to PBOT before it is removed Read Element Status Command The current position of cassettes in the Autoloader can be obtained by a SCSI initiator by issuing a Read Element Status command During all movements of cassettes inside the Autoloader the previous storage element address of the cassette in the magazine is tracked making it unnecessary for this command ever to scan the magazine or otherwise move the mechanism This address is reported in the Source Storage Element Address of the element descriptor the address is valid when the SVALID bit is one Initialize Element Status Command The host computer can direct the Autoloader to scan its magazine by issuing an Initialize Element Status command If there is a cassette in the DTE it will be returned to its magazine slot before the scan begins and it will remain in the slot after the scan SCSI Interface Description Page 31 General Operation e The Reserve and Release commands may be addressed to either LUN but affect both LUs as a unit In other words if an initiator has reserved either LU then both LUs will reply with a status of Reservation Conflict to most SCSI commands from other initiators This is departure from the SCSI standard but it prevents the situation of each LU being reserved by a different initiator e Busy status affects the Autoloader as one unit LUN 0 is busy when LUN 1 is busy and vice versa e The Ready and Not Ready conditions are report
181. pression enabled set by mode select 03 4 Decompression enabled set by mode select 04 4 Block size used for writing 05 4 Current partition 06 4 Prevent 1 or allow 0 media removal 07 4 Cartridge write protected 08 4 Report setmarks 09 4 Data compression ratio Drive Usage Information Page Page 3C Parameter Code Length Name 01 8 Total arouns written 02 8 Total rewrites 03 8 Total groups read 04 8 Total ecc c3 corrections 05 8 Total rereads 06 3 Total load count Page 72 DDS 4 SCSI Interface Manual Rev B Parameter Code Length Name 07 3 Minutes since last cleanina 08 3 Power on time minutes 09 3 Cylinder on time minutes 0A 2 Cleaning Cartridge count 0B 2 Reserved DC 2 Reserved DD 2 Reserved DE 2 Reserved OF 2 Reserved 10 2 Reserved 11 1 Reserved 12 1 Reserved Completion Status The Completion Status for the LOG SENSE command is shown in the following table Code Message Description 00h 02h Good Status Check Condition Extended Sense Byte 02h Code Message 02h Not Ready 04h Hardware Error 05h Illegal Request 06h Unit Attention Description No cartridge is inserted in the drive Parity error on SCSI bus or drive hardware failure detected The CDB contains an invalid bit The Page Code in the Log Page Header specifies an unsupported log page The parameter pointer is invalid Cartridge was changed prior to accepting this command T
182. ptor Block The following table shows the layout of the Command Descriptor Block Bits Byte 7 6 5 4 3 2 1 0 0 0 0 0 1 0 0 0 1 0 0 0 0 0 Code 2 MSB Count 3 Count 4 Count LSB 5 vendor unique 0 0 0 0 Flag Link This vendor unique field is reserved and must be set to zero Commands Space 11h Page 155 Command Descriptor Block Field Descriptions The following table provides descriptions of the CDB fields Field Name Bytes Bits Description Code 1 0 2 The Code Field designates the desired function as shown below Bits 2 1 0 Function 0 0 0 Space blocks 0 0 1 Space filemarks 0 1 0 Space sequential filemarks 0 1 1 Space to end of recorded data 1 0 0 Space setmarks Count 2 4 This field specifies the number of blocks filemarks sequential filemarks or setmarks to space over A zero value in the Count field causes no media movement and is not considered an error Space by Count Functions The Count field indicates both direction and distance within the current partition A positive value N in the Count field moves the tape forward over N blocks filemarks contiguous filemarks or setmarks A negative value N 2 s complement in the Count field moves the tape backward over N blocks filemarks or setmarks Zero in the count field causes no tape movement and is not considered an error When there are no exception conditions during space functions forward tape motion ends on the EOT side of the last block filemark or
183. ral backup or restore operations on several cartridges The vendor unique page 30 contains statistical information that is DDS specific This DDS information is contained in the Tape Log area on each tape or partition This protected reference data is tabulated and maintained for the particular tape currently being used For pages 2 and 3 the LOG SELECT command is used to preset counts to a specific value or to reset the counts if the maximum count is reached The log sense data is reset on a SCSI Bus Reset or a Bus Device Reset Log sense data is obtained by specifying a log page in the Page code field of the LOG SENSE CDB Only one page of data can be requested by the host of each LOG SENSE command The pages used by the drive are found by reading Log Page 0 Any request for unused pages causes a Check Condition The sense data are then set to Illegal Request Invalid Field in the CDB LOG SENSE Command Descriptor Block The following table shows the layout of the CDB Bits Byte 7 6 5 4 3 2 1 0 0 0 1 0 0 1 1 0 1 E 16 7 40h o o o o die o 20 J PC PagCod 3 0 0 0 0 0 0 0 0 mo c o o o 8 o We 4577 5 MSB Parameter Pointer 6 Parameter Pointer LSB nr MSB Alocaionlengh 8 Allocation Length LSB 9 vendor unique 0 0 0 0 Flag Link This vendor unique field is reserved and must be set to zero Page 58 DDS 4 SCSI Interface Manual Rev B Command Descriptor Block Field
184. rbitration Initiators and Targets assert for control of the SCSI bus The bus is awarded to the device with the highest priority SCSI bus address Page 8 DDS 4 SCSI Interface Manual Rev B Figure 2 1 Phase Sequencing with Arbitration B RESET CONDITION SELECTION OR BUS FREE ARBITRATION PHASE PHASE RESELECTION PHASE COMMAND DATA STATUS OR MESSAGE PHASE Arbitration is won by the highest priority SCSI device when both BSY and SEL are asserted and a delay of at least 1200 nSec 1 bus clear delay 1 bus settle delay occurs before the Arbitration Phase ends and the Selection Phase begins Signal timing is shown in Figure 2 3 and the complete Arbitration Phase protocol is summarized in the following table Figure 2 2 Arbitration and Selection Phase Signal Timing DS CHE Step Procedure 1 The SCSI device first waits for a Bus Free Phase to occur The Bus Free Phase is detected when both the BSY and SEL signals are simultaneously and continuously false for a minimum of a bus settle delay of 400 nSec SCSI Interface Description Page 9 2 The SCSI device waits a minimum of one bus free delay of 800 nSec after detection of a Bus Free Phase before driving any signal The Bus Free Phase occurs after BSY and SEL are both false for a bus settle delay of 400 nSec 3 Following the 800 nSec Bus Free Delay in Step 2 the SCSI device Arbitrates for the SCSI bus by asserting both BSY and its own SCSI ID however
185. rence between the CDB transfer length and the number of actual blocks read e If the Fixed bit is 0 it equals the CDB transfer length The logical position after encountering an end of tape or end of partition error is undetermined Recoverable Data Error If an error is encountered while reading the read retry count in the MODE SELECT Read Write Error Recovery page specifies the maximum number of attempts to reread the data If none of the rereads are successful the error is considered unrecoverable and is reported as such The drive might require as much as six minutes to complete its error recovery procedure Unrecoverable Data Error If an Unrecoverable Data Error is encountered the READ command terminates with Check Condition and a Medium Error 03h sense key If the Valid bit byte O bit 7 is set Residual Length field equals the difference between the requested Transfer Length and the actual number of blocks or bytes transferred Incorrect Length Reading fixed and variable length blocks varies according to the setting of the Fixed bit When the Fixed bit is set 1 one or more tape blocks can be read The CDB Transfer Length field specifies the block count to read The block size is the current block size of the drive which is set to 512 at power up or after a SCSI Bus Reset The host can change the current block size by issuing a MODE SELECT command with a new block descriptor parameter that specifies a new block
186. rget has the option of disconnecting from the SCSI bus When the Target needs to again establish the link to its original Initiator the Target reselects that Initiator When selection is made no restrictions on the sequences between Information Transfer Phases exist A phase type may be followed by the same phase type For example a data phase may be followed by another data phase A device that wins Arbitration assumes the roll of Initiator by releasing the I O signal The Initiator sets the data bus to a value that is the OR of its SCSI ID bit and the Targets ID bit The Initiator waits at least two deskew delays 90 nSec before releasing the BSY signal and an additional bus settle delay 400 nSec before looking for a response from the Target A device that loses Arbitration must release the Select ID and BSY Operation enters the Selection or Reselection Phases when a particular device wins a request in Arbitration and gains control of the SCSI bus These phases allow the device in control of the bus to select another specific device connected to the SCSI bus for communication Page 10 DDS 4 SCSI Interface Manual Rev B For example the Initiator can select a tape drive to begin an operation or the tape drive can reselect an Initiator to continue an operation previously disconnected The tape drive does not disconnect from the bus unless the host asserted the host ID bit during selection and the host sent an Identify message of COh
187. ridge was changed prior to accepting Attention this command The drive was reset prior to this command 08h Busy Tape is being initialized after cartridge insertion or the drive is executing a previous immediate command Page 160 VERIFY 13h DDS 4 SCSI Interface Manual Rev B The VERIFY command verifies one or more blocks of data beginning with the next block from the tape unit The command terminates after the specified number of bytes or blocks are verified or when the drive encounters a filemark the EOT or an unrecoverable error On completion the medium is positioned after the last block verified or after a filemark If a VERIFY with a zero verification length is issued no data is verified and the current position on the tape does not change This condition is not considered an error VERIFY Command Descriptor Block The following table shows the layout of the Command Descriptor Block Bits Byte 7 6 5 4 3 2 1 0 0 0 0 0 1 0 0 1 1 1 0 0 0 0 0 0 0 Fixed 2 MSB Verify Length 3 Verify Length 4 Verify Length LSB 5 vendor unique 0 0 0 0 Flag Link This vendor unique field is reserved and must be set to zero Command Descriptor Block Field Description The following table defines the fields in the CDB Field Name Bytes Bits Description Fixed 1 0 If this bit is 0 block is variable length IF this bit is 1 blocks are fixed Block length Size bit Verify 2 4 This field specifies the number o
188. ridge was inserted It is incremented by Frames one each time a series of frames is rewritten Frames are rewritten following an error detected by the RAW check If the data written during the rewrite is also found to be bad by the RAW check the series of frames is rewritten again and this count is incremented by 1 again Current 0003 3 This count is the number of groups read from the cartridge Groups Read since it was inserted Current ECC 0004 2 This count is the number of times the drive used the C3 ECC C3 Corrections correction to recover data from the partition since the cartridge was inserted Previous 0005 3 This count is the number of groups written to the partition Groups during the last cartridge usage cycle Written Previous 0006 2 This count is the number of frames rewritten in the partition Rewritten during the last cartridge usage cycle It is greater than or equal Frames to the last current rewritten frames count prior to the Tape Log being updated when the cartridge is ejected Previous 0007 3 This count is the number of groups read from the partition Groups Read during the last cartridge usage cycle Page 70 DDS 4 SCSI Interface Manual Rev B Name Code Length Description Previous ECC 0008 2 This count is the number of times the drive used C3 ECC C3 correction to recover data from the partition during the last Corrections cartridge usage cycle Total Groups 0009 4 This count is the number of groups
189. rrssrrrnnsrnnsnrens 77 Parameter List Block Descriptor sese 77 Parameter List Block Descriptor Field Descriptions 78 Mode Page Format oce a eee eode t e ve nde do dcn 78 Completion Status eint eet e Eo et etel 90 MODE SENSE REI E 91 MODE SENSE Command Descriptor Block 91 Command Descriptor Block Field Description 92 MODE SENSE Parameters AA 93 Parameter List Header Field Descriptions A 93 Parameter List Block Descriptor sse enne 94 Parameter List Block Descriptor Field Descriptions ssessssse 94 Mode Page Format iri ea cae te ERE HERR E ERES REESE hs 95 Completion Gtaius eene entente tenens 103 MOVE MEDIUM Autoloader only AB 104 MOVE MEDIUM Command Descriptor Block 104 Completion Statue edd eee ite esae dn ae tL dde a eod de ded donas 105 PREVENT ALLOW MEDIA REMOVAL ER 106 PREVENT ALLOW MEDIA REMOVAL Command Descriptor Block 106 Command Descriptor Block Field Description 106 Completion Status unten tie aiite t M aset eec 106 el SEIT EE EE 107 READ Command Descriptor Block 107 Command Descriptor Block Field Description 107 Description of the READ Commande 108 Completion Gtaius enne nnne nnne 111 READ BLOCK EIMI TS 05h rr Pe eite ne eee tre ieu dec 112 READ BLOCK LIMITS Command Descriptor Block 112 Command Descriptor Block Field Description 112 Block Size Defin
190. ry Page and so forth the drive terminates the MODE SELECT command and returns a Check Condition status bytes with an Illegal Request sense key The Additional Sense Code and Additional Sense Code Qualifier are set to Invalid Field in Parameter List Commands Mode Sense 1 Ah Page 89 MODE SENSE 1Ah The MODE SENSE command allows the host to determine various drive device parameters These parameters are sent from the drive to the host as data formatted in a parameter list This command is a complementary command to the MODE SELECT command The drive terminates execution of the MODE SENSE command as follows e When the number of bytes specified in the Allocation Length field have been sent to the host or e When all available MODE SENSE data has been sent to the host During execution of this command the drive does not disconnect from the host Also this command performs no media access If a MODE SELECT command has not been performed since power on SCSI Reset the default mode parameters are in effect All MODE SELECT parameters may be rounded up or down as appropriate A MODE SENSE command may be issued after a MODE SELECT command to determine which parameters have been rounded MODE SENSE Command Descriptor Block The following table shows the layout of the CDB Bits Byte 7 6 5 4 3 2 1 0 0 0 0 0 1 1 0 1 1 0 0 0 0 DBD 0 0 0 2 PC Page Code 3 0 0 0 0 0 0 0 0 4 Allocation Length 5 vendor unique 0 0 0 0 Flag
191. s Commands Mode Select 15h Page 83 Field Name REW bit EEG SEW bit Bytes 8 10 10 Description The default value for the REW bit is 0 The Report Early Warning REW bit determines whether or not the drive reports an early warning condition on a read operation The effect of this bit is different for read and write operations For read type operations if this bit is 0 the drive does not report the early warning condition This setting is recommended for applications where the intent is to read data from tape until the end of recorded data EOD or end of partition EOP is reached If this bit is 1 the drive returns a Check Condition status with an End of Medium EOM bit of 1 when the logical early warning position is encountered during read type operations For write type operations the drive always reports the Check Condition status when the logical early warning position is encountered during a WRITE command The intent of this action is to warn the host that the EOP is approaching and that any additional data will be written at the risk of an unexpected EOP If REW 1 and SEW 0 the drive returns a Check Condition status with the sense key set to Volume Overflow when the early warning position is encountered during write operations Not supported must be set to 1 If the Synchronize at Early Warning SEW bit is set to 1 the default value it causes the drive to flush all buffered write data t
192. s Any SCSI device can create a reset condition by asserting a RST signal for a minimum reset hold time of 25 microseconds The DAT drive never asserts reset During the Reset Condition all SCSI devices release all SCSI signals except RST within a Clear Reset Delay 800 nSec of the transition of RST to low The Bus Free phase always follows the Reset Condition When a reset is issued to the DAT drive the SCSI bus clears all uncompleted commands releases all SCSI device reservations sets the DAT drive to default modes and returns to the Bus Free phase Unit Attention Condition The Unit Attention condition in the DAT drive typically results from the following conditions e A Reset was previously issued to the DAT drive e The DAT drive has just been powered on e The cartridge was removed when the tape is positioned away from BOT e The cartridge was removed when the tape is positioned at BOT following a LOAD command e Acartridge has been inserted since the previous bus reset or power on e A log exception condition occurred e The mode pages have been changed The Unit Attention Condition persists for an Initiator until the Initiator issues a command other than Inquiry for which the DAT drive returns with a Check Condition Status If the next command from that Initiator following the Check Condition Status is Request Sense then the unit attention sense key is returned If the Inquiry Command is received from an Initiator with
193. s Device Reset messages to the drive e fthe command is from the same initiator to the same LUN the current command terminates with a Check Condition and an Abort Sense Key When the disconnected drive is ready to reconnect with the Initiator it does the following 1 It monitors the bus waiting for a Bus Free Phase to occur When a Bus Free Phase is sensed the DAT drive arbitrates for the bus 2 If it wins arbitration the DAT drive then attempts to reselect the Initiator If the Initiator fails to respond in 250 mSec the drive drops all bus signals and allows the bus to again enter the Bus Free Phase The drive then repeats the attempted Arbitration SCSI Interface Description Page 27 3 When the DAT drive has successfully reselected the Initiator it sends an Identify Message to reestablish the path between the drive and the Initiator This message is always 80h because the DAT drive is initiating the reselection and is always LUN 0 A Restore Pointers Message is implied when the DAT drive sends an Identify Message to the Initiator The Initiator responds accordingly SCSI Memory Address Pointers SCSI provides for two sets of three pointers within each Initiator When a physical path is established with a host and this path can accommodate disconnection and reconnection the host must ensure that its Current Pointers for the path are equal to the Saved Pointers in the DAT drive An implied Restore Pointers Operation occurs i
194. s offer electronically erasable programmable read only memory flash EEPROM for SCSI firmware which enables qualified Seagate OEMs to download revised firmware to the drive via two methods using the SCSI bus or using a specialized Seagate firmware tape cartridge About This Manual The information in this manual applies to DDS 4 and DAT 72 drives and autoloaders For specific installation and operational information including SCSI connection information refer to the Installation Guide or Product Description Manual for the specific model of your drive or Autoloader The following table outlines the chapters in this manual Chapter Title Description 1 Introduction Introduces the SCSI interface and explains the structure of this manual 2 SCSI Interface Provides general information about the SCSI Description interface for the DDS 4 and DAT 72 drives 3 Commands Lists and describes the SCSI commands Page 2 DDS 4 SCSI Interface Manual Rev B SCSI Interface Description 2 Overview The Seagate DDS 4 and DAT 72 drives are designed to operate with the Small Computer System Interface SCSI bus This chapter discusses SCSI bus operation as it pertains to drive functions SCSI is a standard interface established to support peripheral equipment such as printers tape drives magnetic disks optical disks for microcomputers and other computer systems The SCSI bus can support up to eight devices consisting of any multiple of host adap
195. scription 42 Standard INQUIRY Data Format 43 Standard INQUIRY Data Format Field Descriptions s sssesseeeseeesseeeereesrnese nees 43 INQUIRY Drive Serial Number Data Format Page 45 Drive Serial Number Data Format Field Descriptions 0sseesseesseeesseenee ereen 45 Completion Status AEN 45 FOAD UNEOAD EE 46 LOAD UNLOAD Command Descriptor Block 46 Command Descriptor Block Field Description 46 E ele E ie TEE 47 LOGATE UE 48 LOCATE Command Descriptor Block 48 Command Descriptor Block Field Description 48 LOCATE and the BT Bit ener nnne 49 Completion Status 2 0 tid dedi ate DRE bie i ordo oue Pe btt pda 50 Bolega e EE 51 LOG SELECT Command Descriptor Block 51 Command Descriptor Block Field Description 52 Errors Detected in the Command Descriptor Block 52 Use ofthe PC BIS iiu oe eee ast ean er ento 52 LOG SELECT Parameter Data 53 BOERNE ACIB EE 58 LOG SENSE Command Descriptor Block 58 Command Descriptor Block Field Description 59 Using Page Control Dis 60 Using the Parameter Pointer Field AA 61 Eog Sernse Pages t saec inia mentale ident 61 Completion Status imos d ded rea dazu a ede eve i ned dE 73 Page vi DDS 4 SCSI Interface Manual Rev B MODE SEEEGT T5h 2i ndn e c ER et euh dens 75 MODE SELECT Command Descriptor Block 75 Command Descriptor Block Field Description 76 MODE SELECT Parameiers enne nnne nene 76 Parameter List Header Field Descriptions ssseesssseessssirssesrrsssri
196. se Data Length 1 Medium Type Field 2 WP BUF BUF BUF 0 0 0 0 3 Block Descriptor Length Parameter List Header Field Descriptions The following table defines the fields in the MODE SENSE Header Field Name Bytes Bits Description Mode 0 This field specifies the number of bytes in the following Mode Sense Sense data that is available to be transferred If the Transfer Length is smaller Data than the MODE SENSE Data Length only Transfer Length bytes of the Length MODE SENSE data are transferred The Sense Data Length does not include itself BUF 2 6 4 When this field is 1 the drive operates in buffered mode In buffered mode a WRITE command is terminated when the data is transferred to the internal buffer of the drive When this field is 0 the drive is in unbuffered mode and all data is written to tape before command completion is returned In non buffered mode a WRITE command is not terminated until all data has been transferred to tape WP 2 7 If this bit is 1 the tape is write protected If this bit is 0 the tape is write enabled Page 92 DDS 4 SCSI Interface Manual Rev B Field Name Bytes Bits Description Block 3 This field indicates the number of bytes of block descriptor information Descriptor that follow the parameter header Length If the DBD bit is set to 1 the block descriptor length is set to 0 00h which indicates that no block descriptor is returned in the MODE SENSE data If the DBD bit is set to
197. sed to Logical Unit Number 0 and SCSI Medium Changer SMC commands to LUN 1 SCSI Primary commands SPC may be addressed to either LUN The Standard Inquiry Data of LUN 0 reports a Peripheral Device Type of 01h sequential access device and a MCHNGR bit of 0 LUN 1 reports a Peripheral Device Type of 08h medium changer device By contrast Scorpion 240 is not a SCSI 3 attached medium changer device These devices have only logical unit 0 and all commands are addressed to that LUN Their Inquiry data has a Peripheral Device type of 01h and MCHNGR bit of 1 Sense data is maintained for each Initiator Target nexus in other words while the Request Sense command may be addressed to either LUN the same data is reported for each LUN SCSI Medium Changer Commands Element Addresses SMC commands control the process of moving cassettes volumes between the magazine and the drive They refer to the components of the Autoloader by element addresses Element addresses are not to be confused with SCSI ID or LUN e The medium transport element MTE is the elevator which actually moves the cassettes its element address is 0 The MTE may not be either the source or destination when a cassette is moved e The data transfer element DTE is the DAT drive itself Its address is 1 e The storage elements SE are the slots in the magazine Slot 1 has element address 2 slot 2 has address 3 etc through address 7 for slot 6 Page 30 DDS 4
198. setmark and reverse motion ends on the BOT side of the last block filemark or setmark If a filemark or setmark is encountered while spacing over blocks or a setmark is encountered while spacing filemarks a Check Condition Status is returned The Sense FM bit is set unless a setmark is encountered and RSMK 0 The Sense Valid bit is set indicating Residual Length is non zero The Residual Length equals the difference in the requested count and the actual number of blocks spaced over not including the filemark or setmark The tape is positioned on the logical EOT side of the filemark or setmark if movement was forward or on the logical BOT side of the filemark or setmark if movement was reverse If EOD is encountered while spacing forward Check Condition is returned with 08h Sense Key Extended Sense Valid bit is set indicating Residual Length is nonzero If BOT is encountered while spacing in reverse Check Condition is returned with 40h Sense Key Extended sense Valid bit is set indicating a nonzero Residual Length If EOT is encountered while spacing forward Check Condition is returned with 40h or 43h Sense Key Extended Sense Valid bit is set indicating a nonzero Residual Length Page 156 DDS 4 SCSI Interface Manual Rev B e lf an unrecoverable data error is encountered Check Condition is returned Extended Sense Key is set to Medium Error and Extended Sense Valid bit is set indicating Residual Length is nonzero Space
199. sibility for the accuracy completeness sufficiency or usefulness of this manual nor for any problem that might arise from the use of the information in this manual Contents Page iii Contents Introduction 1 MEDIE tees 1 Drive Oger eeh Lee ee bat iene etate eiat ue 1 About This Manual c deme t Mh deed 1 SCSI Interface Description 2 educ EE 2 ANSLSCSI Bus Standard S iem eA Peeters 2 Cabling and Connectors eene enne nnns 2 Signal Descriptions vive o eroe ig i Ee ee a a ene aah Ae adv uq ag d dg o aas 3 Command Set Description s neei iaia aieia eaaa iaaa aae aaia aieiaa iaaa 4 ANSI X3 131 199x Conformance Statement SCSI 2 sss 5 General featutes aerae a EARE E A 5 Interface standards Contommance sese 5 E lun le EE 6 Autoloader only commande 6 Oe tibia ego te eed nsa tee bevel wi geste Lent 6 Vendor unique Commande AA 6 SCSI Bus e ee EE 6 Waiting and Control Phases cccccceceeeeeneceeeeeeeaeeeceaeseeeeeseaeeesaaeeseaeeseeeeesaeeeeeneeee 7 Arbitrating SYSlOMS sissies itt etd a eee d c HR ass 7 Selection and Reselection Dhases nenne 9 Select With Attention AA 10 Identity Message ime ceci scene b acp rl ea ae Fete pet dde et 10 Information Transfer Phases nennen nnne nnns 11 Asynchronous Data Transter 11 Synchronous Data Transfer 13 Command lu EE 14 Data PHASE ceea TA 15 Data lri GET 15 D r Qut Phase o reo ea n reo er P RO GE DER IRR 15 Status PNAS C TED 1
200. specified in the Page Code field An EVPD bit of 0 specifies that the drive return the standard INQUIRY data Page Code 2 The Page Code field specifies which page of vital product data information the target returns Allocation 4 This field specifies the number of bytes that the Initiator Length allocated for the response data The drive transfers the number of bytes specified up to a maximum of 36 An Allocation Length of zero indicates that no data can be transferred This length is not considered an error Page 42 DDS 4 SCSI Interface Manual Rev B Standard INQUIRY Data Format The following table shows the standard data format for the INQUIRY command Bits Byte 7 6 5 4 3 2 1 0 0 Peripheral Device Type 1 0 0 0 0 0 0 0 2 0 0 0 0 0 ANSI Version 2 3 0 0 0 0 0 0 1 0 4 Additional Length 1Fh 5 0 0 0 0 0 0 0 0 6 0 0 0 0 0 0 0 Addr16 7 0 0 1 1 1 0 0 0 8 15 MSB Vendor Identification Vendor Identification LSB 16 27 Product Name 28 31 Product Revision Level 32 35 Firmware Version Indicates Seagate specific field definitions In the SCSI standard bytes 16 31 are grouped as Product Identification and bytes 32 35 are captioned Product Revision Level Standard INQUIRY Data Format Field Descriptions The following table describes the data format fields Field Name Bytes Bits Description Peripheral Device 0 0 7 This field is set to 01h to indicate a sequential access device Type This fiel
201. status for the INITIALIZE ELEMENT STATUS command Code Message Description 00h Good Status The magazine has been initialized and positioned The drive is ready to accept another command 02h Check Condition Extended Sense Byte 02h Code Message Description 02h Not Ready No magazine is present 04h Hardware Error Parity error on SCSI bus or drive hardware failure detected 05h Illegal Request The CDB contains an invalid bit 06h Unit Attention The cartridge was changed prior to accepting this command The drive was previously reset Commands Inquiry 12h Page 41 INQUIRY 12h The INQUIRY command requests that the drive return parameter information If an INQUIRY command is received from an Initiator with a pending Unit Attention Condition before the drive reports Check Condition status the drive performs the INQUIRY command and does not clear the Unit Attention Condition INQUIRY Command Descriptor Block The following table shows the layout of the CDB Bits Byte 7 6 5 4 3 2 1 0 0 0 0 0 1 0 0 1 0 1 0 0 0 0 0 0 0 EVPD 2 Page Code 3 0 0 0 0 0 0 0 0 4 Allocation Length 5 vendor unique 0 0 0 0 Flag Link This vendor unique field is reserved and must be set to zero Command Descriptor Block Field Description The following table defines the fields in the CDB Field Name Bytes Bits Description EVPD 1 0 An Enable Vita Product Data EVPD bit of 1 specifies that the drive return vital product data
202. ste nennen trennen eren nennen 151 REWINDB 01h 5 2i tt tet e eet te e ett 152 REWIND Command Descriptor Block 152 Command Descriptor Block Field Description 152 Completion Status fansite teo e ete eite ates 152 SEEK BEOGK 0Gh ode e eect 154 SEEK BLOCK Command Descriptor Block 154 Command Descriptor Block Field Description 154 Completion Status ier ferte eim esci ceste esas er teste Eee ae te ete Penne 155 SEND DIAGNOSTIC OD 156 SEND DIAGNOSTIC Command Descriptor Block 156 Completion Status rite aed ENEE CIR ia ERR LARES deuda 157 SPAGE 11h EE 158 SPACE Command Descriptor Block 158 Command Descriptor Block Field Descriptions sseesssssss 159 Space by Count Functions sse nennen 159 Space by Position Functions sese 160 Space and the RSMK BIE i i ee teo cec eaa 160 Completion Status n irit pd ue ne E d dea Eie eie 161 TEST UNIT READY OO eerste deed idee d imde ege 162 TEST UNIT READY Command Descriptor Block 162 TEST UNIT READY Detailed Operation 162 Completion Gtatus enne 163 Missi ras me 164 VERIFY Command Descriptor Block 164 Command Descriptor Block Field Description 164 Data Blocks Verified es eiit teret etti eu t ek idees 164 Completion Gtaius eene nnne nennen 165 WRTA CAN ni ee e e D RR ete D ARN RS 166 WRITE Command Descriptor Block sse 166 Command Descriptor Block field description 166 Completion Status rete c
203. t may initiate an SDTR to establish a new synchronous data transfer agreement or to end a previously arranged synchronous data transfer agreement and return to asynchronous data transfer mode The following table shows the format for the SDTR message Byte Value Description 0 01h Extended message 1 03h Extended message length 2 01h Synchronous Data Transfer Request Code 3 m Transfer Period m x 4 nsec 4 W REQ ACK Offset Transfer Period can be any value between OAh and 64h Exceptions to m x 4 nsec are made in the following cases 1 If the value is OCh which is defined in SCSI 3 as a period of 50 nsec 2 If the value is OBh which sets the period to 37 5 nsec and 3 If the value is OAh which sets the period to 25 nsec REQ ACK Offset can be any value between 4 and 32 The Transfer Period is the minimum time allowed between leading edges of successive REQ pulses and of successive ACK pulses to meet the requirements of the drive for successful reception of data The host and DAT drive can transfer data with larger but never smaller Transfer Period than specified in the SDTR message Page 14 DDS 4 SCSI Interface Manual Rev B The minimum value fo the Transfer Period 25 nsec is determined by the maximum burst transfer rate of the SCSI interface hardware of the drive and is 80 Mbytes per second 06h The host must specify a Transfer Period that allows it to successfully receive data from the DAT drive during the Data
204. table the data block in block number 1 together with five setmarks in blocks number 12 6 are considered as one logical block If the RSMK bit is 1 in the CDB when the SPACE command is issued then the setmark is recognized and reported during execution of the SPACE operation The following table shows the logical blocks Commands Space 11h Page 157 Referring to the first table the table below shows the tape position after each SPACE command is complete SPACE X Blocks From RSMK bit Tape Position 1 BOT ON B 7 EOD ON E 1 BOT OFF E 7 EPD OFF E 2 BOT ON C chk cond res 1 8 EOD ON D chk cond res 1 2 BOT OFF F 8 EOD OFF A Completion Status The Completion Status for the SPACE command is shown in the following table Code Message Description 00h Good e The drive is ready to perform any appropriate command Status e The drive remains in any previously set mode e The tape is positioned on the EOT side if space forward and on the BOT side if space reverse 02h Check Extended Sense Byte 02h Condition Code Message Description 02h Not Ready No cartridge is inserted in the drive 03h Media Error Unrecoverable data error encountered while performing a SPACE command 04h Hardware Error Drive hardware failure detected 05h Illegal Request The CDB contains an invalid bit 06h Unit Cartridge was changed prior to accepting Attention this command The drive was reset prior to this command 0
205. teria TMC field specifies how and when a log exception is to be reported to the host The Enable Threshold Comparison ETC bit enables or disables the generation of a Check Condition for log exceptions of individual log parameters The Report Log Exception Condition RLEC bit of the MODE SELECT SENSE Control Mode Page when set allows the generation of a Check Condition for log exceptions for each log parameter whose ETC bit is set An RLEC bit of zero globally disables all log exception Check Conditions regardless of the ETC bit value of each log parameter When the ETC bit is set 1 and the RLEC bit is set in the MODE SELECT SENSE Control Mode Page a Check Condition is generated each time the accumulated value is incremented and the threshold condition is met as described in the following paragraphs When a counter is incremented by the drive a check is made to determine if the threshold comparison is enabled according to the ETC bit for the counter being incremented If comparisons are enabled the new accumulated value is compared with the threshold value according to the Threshold Met Criteria for the counter When the criteria are met and the RLEC bit is set in the MODE SELECT SENSE Control Mode Page a log exception Check Condition is returned for the next command The sense key is set to Unit Attention 06 the additional sense code is Page 56 DDS 4 SCSI Interface Manual Rev B set to Log Exception and the additional s
206. ters and peripheral devices The Seagate DDS 4 and DAT 72 drives comply with SCSI 2 and SCSI 3 specifications In a few cases vendor unique features are available These features are compatible with the SCSI standards The interface is a sixteen port daisy chained bus using twenty seven signal lines eighteen data bit signal lines and nine control lines The eighteen data bit lines are made up of two pairs of eight data signal lines and one parity bit line The remaining nine lines provide control and status signals to coordinate data transfer operations between the host controller and the selected drive The drives have an internal SCSI controller integrated into the drive electronics Each device ID on the SCSI bus may drive up to 8 logical units LUN These drives support only LUN 0 except for the Autoloader which also uses LUN 1 ANSI SCSI Bus Standards In addition to the information presented in this manual we recommend that for SCSI 2 read the ANSI Working Draft Revision 10 standard before writing host software drivers Also see the conformance statements which are given in the Product Description Manual for the each model of drive or Autoloader Cabling and Connectors The cabling requirements and pin outs for the SCSI connector for the internal drive models are given in the respective installation guide and Product Description Manual for each model of DAT drive or Autoloader SCSI Interface Description Signal Descriptions
207. the Data Out phase A 0 length indicates that no parameter data is to be transferred to the target Errors Detected in the Command Descriptor Block The following conditions constitute errors that may be detected by the drive in relation to the CDB These errors cause a Check Condition The request sense data is set to Illegal Request Invalid Field in the CDB e fthe PCR bit is set and the parameter list length is not 0 e A parameter list length that would cause a parameter within a valid page to be truncated or otherwise incompletely initialized e The settings of the PC bits select the default threshold or default accumulated values and the parameter list length is nonzero Use of the PC Bits The Page Control bits byte 2 bits 6 7 define the type of parameter values that are to be sent to the drive The following table lists the Page Control bit values for the LOG SELECT CDB Bit 7 0 0 1 1 Bit 6 0 1 0 1 Type Requested Counts 0 Threshold values 1 Accumulated values 2 Default threshold values 3 Default accumulated values USE OF DEFAULT VALUES TO SET CURRENT VALUES The threshold values can be loaded with the default threshold values by setting the PC bits to specify the default threshold values The Parameter List Length must be set to O Likewise the accumulated values can be loaded with the default accumulated values by setting the PC bits to specify the default accumulated values The Parameter
208. the drive 04h Hardware Error Drive hardware failure detected 05h Illegal Request The CDB contains an invalid bit 06h Unit Cartridge was changed prior to accepting Attention this command The drive was reset prior to this command NOTE The amber drive LED flashes rapidly if a hardware fault is detected Page 154 DDS 4 SCSI Interface Manual Rev B SPACE 11h The SPACE command uses five methods to move the tape This command moves the position e Forward or backward a specified number of data blocks e Forward or backward a specified number of filemarks e Forward or backward a specified number of setmarks e Forward a specified number of sequential contiguously grouped filemarks or setmarks e Forward to the end of recorded data If the target block or filemark is in the buffer of the drive no tape motion results Otherwise spacing is done at high search speed A file example is shown below Bock Di 2 fa fa s je 7 Is f fio n rw Im Ei eor Lee bata ata Data Em para Data Em para Data em rm rm 3 Position 2 e When SPACE Block count is 4 from BOT SPACE positions the tape to the end of the 4th block position 1 e When SPACE Sequential filemarks count is 2 from BOT SPACE positions the tape to the end of the next occurrence of a double filemark position 2 e When SPACE filemarks count is 5 from BOT SPACE positions the tape to position 3 SPACE Command Descri
209. the header layout for the READ DATA BUFFER command Bits Byte 7 0 0 1 2 3 6 5 4 3 2 1 0 0 0 0 0 0 0 MSB Available length Available length Available length READ DATA BUFFER Header Field Descriptions The READ BUFFER header contains four bytes e The first byte is reserved and set to zero e Bytes one two and three contain the capacity of the space available in the drive buffer This number is not reduced to reflect the Allocation Length nor is it reduced to reflect the actual number of bytes using the WRITE DATA BUFFER command Completion Status The Completion Status for the READ DATA BUFFER command is shown in the following table Code Message 00h Good Status 02h Check Condition Description e The drive is ready to perform any appropriate command e The drive remains in any previously set mode e The tape position is not changed Extended Sense Byte 02h Code Message Description 04h Hardware Error Drive hardware failure detected 05h Illegal Request The CDB contains an invalid bit Allocation Length exceeds the maximum 06h Unit Cartridge was changed prior to accepting Attention this command The drive was reset prior to this command Page 114 DDS 4 SCSI Interface Manual Rev B READ ELEMENT STATUS Autoloader Only B8h The READ ELEMENT STATUS command requests the Autoloader to report the status of its elements to the host The status of ALL element types are reported READ
210. the initial state for the next linked command Page 20 Hex Code Message OBh Linked Command complete with Flag OCh Bus Device Reset Identify 80h disable Disconnect Reconnect COh enable Disconnect Reconnect DDS 4 SCSI Interface Manual Rev B Definition This message is sent from the DAT drive to inform an Initiator that execution of a linked command with the Flag bit set to one is completed and that status was sent The Initiator then sets the current pointers to the initial state of the next linked command Typically this message is used to cause an interrupt in the Initiator between two linked commands This message is sent from an Initiator to direct the drive to clear all current commands it forces the drive to an initial state with no operations pending for any Initiator On recognizing this message the drive moves to the Bus Free Phase All modes are reset to the default state These messages are sent by either the Initiator or DAT drive to establish the physical path between them The physical path connection indicates that both the Initiator and DAT drive have message passing capability Bit 7 is set to one to distinguish these messages from other messages Bit 6 is set to one by the Initiator indicating the Initiator has the ability to accommodate disconnection and reconnection Bits 5 through 3 are reserved set to zero Bits 2 through 0 specify the logical unit number that must be 0 for the DA
211. these values during normal operation Accumulated Values Type 1 accumulated vales is the most common page control bit setting This type requests the current counts for the page These counts reflect the current count of events since the last power on cycle SCSI bus Reset Bus Device Reset or the last LOG SELECT command that cleared or set parameter values Note For pages 30 and 31 the parameter values cannot be changed and are never reset These values represent historical data regarding tape usage and cannot be changed by the LOG SELECT command Page 30 data is written to the tape log when the tape is ejected either manually or through the SCSI UNLOAD command Accumulated values are incremented by the drive as an event occurs These page 2 and 3 values can be updated or initialized by the initiator with the LOG SELECT command Also the default accumulated values all zeros can be loaded with the accumulated values through the LOG SELECT command Because the drive maintains the accumulated values in volatile memory the values may be lost if a power cycle occurs The values for page 30 are saved on the cassette itself and are preserved However if a power cycle occurs before the cassette is ejected the current page 30 data is lost The tape log values cannot be updated if the cassette is write protected Default Threshold Values The type 2 page control bit setting requests default threshold values This request generally retur
212. ting Response after Tape is Out Press eject NOT READY 5A 01 NOT READY 04 03 NOT READY 3A 00 UNLOAD NOT READY 04 03 NOT READY 04 03 NOT READY 3A 00 command IMMED 1 IMMED 1 Insert then eject NOT READY 5A 01 NOT READY 04 03 NOT READY 3A 00 Commands Test Unit Ready 00h Page 159 If a cartridge is in the drive at power up and a TEST UNIT READY command is issued before the tape is positioned at BOT then the following responses occur First TUR Response Response during Tape Loading UNIT ATTN 29 00 NOT READY 04 03 If a cartridge is in the drive at power up and no TEST UNIT READY command is received until after the tape is positioned at BOT then the following responses occur First TUR Response Subsequent TUR Response UNIT ATTN 29 00 GOOD STATUS Completion Status The Completion Status for the TEST UNIT READY command is shown in the following table Code Message Description 00h Good The drive is ready to perform any appropriate command Status e The drive remains in any previously set mode The tape is not moved 02h Check Extended Sense Byte 02h Condition Code Message Description 02h Not Ready No cartridge is inserted in the drive an immediate command execution is in progress or an UNLOAD command has been executed Bytes 12 and 13 of the Sense Data indicate the type of not ready state 04h Hardware Error Drive hardware failure detected 05h Illegal Request The CDB contains an invalid bit 06h Unit Cart
213. tional partitions supported by the drive that can exist on a cartridge The Additional Partitions Defined field specifies the number of partitions to add when formatting the tape This bit may be set by the initiator to 1 dual partitions or 0 single partition which specifies the desired number of additional partitions to format on the tape when the IDP bit 1 or the SDP bit 1 If the SDP bit is set to 1 the drive automatically formats a partition 1 with a capacity of approximately 100 MB The following conditions are also required The Additional Partition byte 1 If the Additional Partition byte 0 the SDP bit is ignored IDP bit 0 The SDP and IDP bits cannot be set at the same time e fthe SDP bit 1 then the Additional Partitions byte must also be 1 CAUTION Setting the SDP bit causes the tape to be reformatted to a 2 partition tape All previous information recorded on the cassette is destroyed If set to 1 the Initiator Defined Partitions bit causes the drive to partition the tape into 1 or 2 partitions as specified by the Additional Partitions Defined field and the partition size descriptors CAUTION Setting the IDP bit causes the tape to be reformatted to a 1 or 2 partition tape All previous information recorded on the cassette is destroyed The partition Size Unit of Measure field defines the units in which the partition size descriptors select the partition size The valid values are 4 3 Unit 0
214. to the Loader The Loader will attempt to scan the magazine place the stray tape into the lowest numbered empty slot and eject the magazine Page 34 DDS 4 SCSI Interface Manual Rev B Commands Introduction This chapter describes the SCSI commands for the Seagate DDS 4 and DAT 72 tape drives Command Reference List This chapter describes the implementation of the ANSI SCSI command specifications The following table lists the commands numerically by opcode Commands specific for the AutoLoader are noted Code nnh 01h 02h 03h 05h 07h 08h OAh OCh 10h 11h 12h 13h 15h 16h 17h 19h 1Ah 1Bh 1CH 1Dh 1Eh 34h 3Bh 3Ch 4Ch 4Dh A5h A6h B8H SCSI 2 Autoloader X DK x x x gt lt gt lt x gt lt x gt lt x x gt lt gt lt x gt lt gt lt gt lt gt lt gt lt gt lt gt lt gt lt gt lt gt lt x lt X gt lt gt lt X gt lt x Command TEST I INIT READY REWIND REQUEST BLOCK ADDRESS REQUEST SENSE READ BLOCK LIMITS INITIALIZE ELEMENT STATUS READ WRITE SEEK BLOCK WRITE FILEMARKS SPACE INQUIRY VERIFY MODE SELECT RESERVE UNIT RELEASE UNIT ERASE MODE SENSE LOAD UNLOAD RECEIVE DIAGNOSTIC RESULTS SEND DIAGNOSTIC PREVENT ALLOW MEDIUM REMOVAL LOCATE READ POSITION WRITE DATA BUFFER READ DATA BUFFER LOG SELECT LOG SENSE REPORT DENSITY SUPPORT MOVE MEDIUM EXCHANGE MEDIUM READ ELEMENT STATUS Comm
215. to the host was compressed using an algorithm other than the DCLZ 21 FF algorithm The contents of the DDS DC entity header algorithm byte are returned Device Configuration Page 10h The Device Configuration page specifies the appropriate sequential access device configuration The following table illustrates this page Bits Byte 7 6 5 4 3 2 1 0 0 0 0 Page Code 10h 1 Page Length OEh 2 0 0 0 DIS RAW ENC3 N Group 3 Active Partition 4 0 0 0 0 0 0 0 0 5 0 0 0 0 0 0 0 0 6 MSB Write Delay Time 7 Write Delay Time LSB 8 0 BIS RSMK 0 0 0 0 REW 9 0 0 0 0 0 0 0 0 10 0 0 0 EEG SEW 0 0 0 11 0 0 0 0 0 0 0 0 12 0 0 0 0 0 0 0 0 13 0 0 0 0 0 0 0 0 14 Select data compression algorithm 15 0 0 0 0 0 0 0 0 Page 98 DDS 4 SCSI Interface Manual Rev B Device Configuration Page Field Descriptions The following table describes the fields in the Device Configuration page Field Name Page Code Page Length DIS RAW EN C3 N Group Active Partition Write Delay Time BIS RSMK bit REW bit EEG SEW bit Select data compression algorithm Bytes Bits 0 0 5 1 2 4 2 3 2 0 2 3 6 7 8 6 8 5 8 0 10 4 10 3 14 Description The Page Code field must be set to 10h to select this page The Page Length field must be set to 14 OEh which indicates that 14 parameter bytes follow the Page Length byte The DIS RAW Disable Read After Write bit enables and disables the read after write cap
216. to two minutes for these tests to complete Only a parameter list of zero is supported A command with the Self Test field set to zero is not an error In this case no diagnostic testing is performed Good status is returned if the test is successful If any test fails the diagnostic is terminated and check condition is returned Additional information about the failed test can be retrieved by the RECEIVE DIAGNOSTIC RESULTS command SEND DIAGNOSTIC Command Descriptor Block The following table shows the layout of the Command Descriptor Block Bits Byte 7 6 5 4 3 2 1 0 0 0 0 0 1 1 1 0 1 1 0 0 0 0 0 Self Test DEVOF Off Line 2 0 0 0 0 0 0 0 0 3 0 0 0 0 0 0 0 0 4 0 0 0 0 0 0 0 0 5 vendor unique 0 0 0 0 Flag Link This vendor unique field is reserved and must be set to zero The combinations of bits in byte 1 are defined as shown in the following table Self Test DEVOF Off Line Description Bit 2 Bit 1 Bit 0 1 0 0 Self test 1 1 1 Enhanced diagnostics read write test Commands Send Diagnostic 1Dh Page 153 Completion Status The Completion Status for the SEND DIAGNOSTIC command is shown in the following table Code Message Description 00h Good e The drive is ready to perform any appropriate command Status The drive remains in any previously set mode The tape position is not changed 02h Check Extended Sense Byte 02h Condition Code Message Description 02h Not Ready No cartridge is inserted in
217. ty error while the host is transferring a CDB the drive e Terminates the transfer e Switches the host to the Status Phase and sends a Check Condition e Switches the host to the Message In Phase and sends a Command Complete e Sets the Sense Key B and ASC ASCQ 47 00 SCSI 2 only If the host detects a parity error while data is being transferred from the drive and asserts ATN the drive e Terminates the transfer of data e Switches the host to the Message Out Phase e Waits for the host to send an 05 Host Detected Error e Switches the host to the Status Phase and sends a Check Condition e Switches the host to the Message In Phase and sends a Command Complete e Sets the Sense Key B and ASC ASCQ 48 00 SCSI 2 only If the drive detects a parity error while the host is transferring data the drive e Terminates the transfer of data e Switches the host to the Status Phase and sends a Check Condition e Switches the host to the Message In Phase and sends Command Complete e Sets the Sense Key B and ASC ASCQ 47 00 SCSI 2 only If the host is in the Status phase and detects an error in the status byte and asserts ATN the drive e Switches the host to the Message Out Phase and waits for the host to send 05 Initiator Detected Error e Switches the host to the Status Phase and sends a Check Condition e Target sends restore pointers and resends Status If the host is in the Message In Phas
218. utoloader uses a six slot magazine that is keyed to prevent incorrect insertion of cassettes into the magazine and incorrect insertion of the magazine into the loader The slots are numbered 1 through 6 with 1 2 and 3 on one side of the magazine and 4 5 and 6 on the other When a magazine is inserted into the loader the door folds down and out of the way and the magazine should be pushed in gently until the loader mechanism begins to draw the magazine in the door must be allowed to close Page 32 DDS 4 SCSI Interface Manual Rev B When the magazine has been completely moved into the loader the process of initialization begins in which the magazine is scanned to determine which slots contain cassettes In fact initialization is performed at three times e Insertion of a magazine into a drive that is already powered up e Power up with a magazine already inside e Receipt of an Initialize Element Status SCSI command Front Panel Operation The front panel contains an LCD screen that displays the autoloader status There are also three pushbuttons Eject Select and Enter which are used to perform various operations e Display drive firmware version and SCSI ID e Select language for LCD messages e Adjust LCD contrast e Enable and disable Autoload mode e Load a specific cassette e Eject the magazine e Lock and unlock the door The menu can only be accessed when there is no magazine in the drive Loading cassettes and ejectin
219. written since the partition Written was formatted This count accumulates over the life of the cartridge but is zeroed if the tape is formatted again Total 000A 3 This count is the total number of times frames were rewritten Rewritten within the partition since the partition was formatted It is Frames incremented by one each time a series of frames is rewritten following an error detected by the RAW check It accumulates over the life of the cartridge but is zeroed if the tape is formatted again Total Groups 000B 4 This count is the number of groups read from the partition Read since it was formatted It accumulates over the life of the cartridge but is zeroed if the tape is formatted again Total ECC C3 000C 3 This count is the number of times the drive used C3 ECC Corrections correction to recover data from the partition since the tape was formatted It accumulates over the life of the cartridge but is zeroed if the tape is formatted again Load Count 000D 2 This count is the number of times the tape has been loaded over the life of the tape since it was formatted One load is the same as a usage cycle inserting using and subsequent ejection of the cartridge It accumulates over the life of the cartridge but is zeroed if the tape is formatted again In a dual partition tape only one load count is maintained Most significant 4 bits are 0 Tape Capacity Page page 31 Page 31 the Tape Capacity page allows you to obtain

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