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RX02 Floppy Disk System User's Guide

1. CONTROLLER M7744 M8256 UNIBUS INTERFACE DISKETTE IA 7015 580 1 uCPU CONTROLLER M8357 OMNIBUS INTERFACE DISKETTE __ ___ 57 OMNIBUS IA 7015 590 BCO5L 15 INTERFACE ml pCPU CONTROLLER M7744 M7846 UNIBUS INTERFACE DISKETTE M7946 BUS INTERFACE ULE IS POSITIONED TO BE COMPATIBLE WITH THE INTERFACE Figure 1 1 Floppy Disk Configuration 1824 Figure 1 2 Front View of the Floppy Disk System 1 3 nr oco zc Yew ZZzOo 2 51 11 11 8 8 11 51 11 1857 CABLE CONNECTION Ed M8357 MODULE RX8E OR RX28 CABLE CONNECTION REV B DEVICE CODE SWITCH M7946 MODULE RXV11 051 15 CABLE CONNECTION 7 9 W10 W11 W12 1415 13 16 W14 W17 REV C amp REVD PRIORITY PLUG CABLE CONNECTION lt lt gt I M7846 MODULE RX11 civ Figure 1 3 Interface Modules 5 15 CABLE CONNECTION p ADDRESS JUMPERS 8029 MODULE RXV21 ADDRESS SWITCH 051 15 OFF 1 PRIORITY PLUG CABLE CONNECTION VECTOR SWITCH ON 1 M8256 MODULE 211 2710 1 2 2 Microprogrammed Controller The M7744 microprogrammed controller module is located in the RX02 cab
2. 4 11 I IN 4 11 bell bowen aa a diene 4 11 RA T 4 12 RX8E Programming 4 13 Write Write Deleted Data Read 4 13 Empty Buller or Dx o Mau ec 4 13 o me a ai aee Mesdames 4 13 X25 Propramming reed Dui ass 4 17 Restrictions and Programming 11 4 22 1 AND 1 PROGRAMMING INFORMATION e 4 23 Register and Vector 04 4 4 4000 0 0 2 4 23 Keeister DesoripHOTL s _____ 4 24 RXCS Command and Status 177170 4 24 RXDB Data Buffer Register 177172 2 4 25 KATAR Track pt acabe 4 25 RXSA 5 aao eve 4 25 Data unc eam pd 4 25 EXES Error and Status ERE 4 26 Function OC CS 4 27 Butter a re ps
3. KR XV2L tita dudar 4 38 RAZSA Format D E 4 38 4 38 RX2BA and RX2DB Format RX211 RXV21 4 38 RAZES Format CRAZE RAVAL 4 39 RX211 RXV21 Write Pill Buffer 4 45 RX2l I1 RXV21 Read Empty Buller Example 4 46 vii TABLES Title Page Data Address Ee epic EE 1 13 8 2 4 Controller Configuration Switch Positions 4 0 2 ene 2 4 Interface Code Jumper Configuration 2 9 Operator Troubleshooting Guide soos tno tes uot tv pU tet 3 3 Device Switch Selectio so aa RERO cable van b cu deu 4 2 viil This manual is intended to provide the user with sufficient information to correctly set up and operate the 02 Floppy Disk System in any of the various configurations that are available for use with the PDP 8 PDP 11 or LSI 11 computers The manual presents general installation user and program ming information for the 02 Floppy Disk System and the interface options associated with the PDP 8 PDP 11 and LSI 11 computer systems 1 GENERAL INFORMATI
4. SET FOR DONE FLAG 229 2351 5381 FILL YW FLAG SET ela 332 6745 0N 5 FOR DONE FLAG 211 9334 5527 JMP L30P 7407 TR OR DONE 212 213 DINE FLAG 13 SET ela 215 YEST FOR ANY 93795 216 217 2334 5785 SER TEST FOR THE FLAG 216 7335 7442 MLT ERRORS 955 219 ee AND TEST THE 209 PRUGHAYM LOCATION ETRY 22 eee AND QETRY THE CO 4AND JNTTL THE ERROR RECOVERS 223 22a 03 THE COUNTER 049 TO 225 226 2336 2272 187 ETRY 227 5337 5324 JMP SETUP FILL THE SECTOR BUFFER 226 agar 7422 LT PARITY ERROR 229 23 ATAF T3ANSFER 5 FLAG 18 SET 231 515 YRANSFER HATA 9834 THE RIGIAYS BUFFER TO THE SECTOR BUFFER 234 9341 18412 FILL TAD 1 A1 AJTO INDEX REGISTER jn 235 342 6722 THE RXO1 SECTOR B3uFFERQ 25 9383 7222 CLA CL RECAUSE XNR 7068477 237 2394 5527 J P 1209 IOP UNTIL THE DONE FLAG SETS 1873 Figure 4 15 28 Fill Buffer Example 4 20 238 239 24 281 282 283 284 235 246 047 988 249 258 251 252 233 254 255 256 257 256 259 262 261 262 263 264 265 266 267 268 269 276 271 272 273 274 275 276 877 278 279 28a 281 282 283 284 285 286 287 288 289 692 291 292 293 994 995 296 297 296 299 390 381 382 303 324 525 386 327 328 3
5. 10 TO LOAD TRACK CLA CLA BECAUSE 107 KOR DOESN T THE SECTOR ANO TRACK ADDRESSES HAVE BEEN TRANSFERRED TO THE RX24 VIA THE FOR THE DONE FLAG AND CHECK FOR ANY ERRORS 1F THE FUNCTION HAS COMPLETED SUCCESSFULLY NO ERROR FLAG THEN HALT SON 7401 67 8 TO JMP od WALT FOR DONE FLAG SER 10 67X4 SAMPLES ERROR FLAG HLT a COMPLETED THE ERROR FLAG IS SET CONTENTS OF THE TRANSFER REGISTER IS THE ERROR STATUS F TRANSFER REGISTER BITS 18 AND 11 2 THEN SoME SEEK ERROR HAS OCCURED TRANSFER REGISTER 11 1 THEN A ERROR HAS OCCURED iF TRANSFER REGISTER BIT 10 1 THEN A PARITY ERROR HAS OCCURED XOR GET CONTENTS OF TR ERROR STATUS ASTATUS AND SAVE CLL CLA RAL 2 ANO ASTATUS YEST FOR PAR TY ERROR SNA CLA 5 PARITY ERROR JMP TCRC NOT A PARITY ERROR MAYBE CRC 7A PARITY ERROR HAS OCCURED INCREMENT TEST THE PARITY ERROR RETRY COUNTER PROGRAM LOCATION PTRY ANO RETRY THE COMMAND UNTIL THE PARITY ERROR RECOVERS ZOR UNTIL THE PTRY COUNTER OVERFLOWS 0 15 PTRY JMP RETRY RETRY THE COMMAND HARD PARITY ERROR ERROR FLAG 15 SET BUT THE ERROR 15 NOT A PARITY ERROR TEST ERROR TORC CLA ANO 5 5 TEST FOR A ERC ERROR SNA CLA SKIP IF CRC ERROR JMP SEEK NOT MUST A SEEK
6. 28 0 01 4 5 Format RASE 4 6 RX 25A Format R ASE 4 6 RAZ DB Format 28 4 7 RXESTOHUJALUSASE 4 7 Pormat bab Mate 4 8 RXSE Write Write Deleted Data Read 00022 4 15 Empty Uo oed e toas dio 4 17 KAM tenet 4 18 RX28 Write Write Deleted Data Read Example 4 19 Bulfer Exa Mp C esne ede 4 21 RAZS Empty Buller EXAHDpIle iue uoc Da Doe 4 22 RACS Forma 4 25 a 4 26 RASA Formali OR ATI yas Oat 4 26 RADB Forma V TT 4 26 Format 6 5205 4855 n 4 27 RXII RXVII Write Write Deleted Data Read 4 32 RALT RAY Butler 4 33 RADI PRAY PP Buffer Example 4 34 RAZCS Format R cub ween 4 36
7. LO US 4 27 Empty Buller OO 4 27 mem 4 28 Read Laici 4 28 Read Status 4 29 Write Sector with Deleted Data 110 4 29 Read Error Code Function CET 19 ade ter ea 4 29 4 2 3 8 4 2 4 4 2 41 4 2 4 2 4 2 4 3 4 2 5 4 2 6 4 3 4 3 1 4 3 2 4 3 2 1 4 3 2 2 4 3 2 3 4 3 2 4 4 3 2 5 4 3 2 6 4 3 2 7 4 3 2 8 4 3 3 4 3 3 1 4 3 3 2 4 3 3 3 4 3 3 4 4 3 3 5 4 3 3 6 4 3 3 7 4 3 3 8 4 3 3 9 4 3 4 4 3 5 4 3 5 1 4 3 5 2 Figure CONTENTS Cont Page PO WOE enin Do RID held 4 29 Programming Examples deep 4 30 Kead Data WIHe UM Sdn 4 30 Empty Buffer Funcom eio p 4 30 Falb B ller 4 30 Restrictions and Programming 5 2 2 2 22 4 30 Error M THE 4 34 RX211 AND RXV21 PROGRAMMING INFORMATION 4 34 Register and Vector Addresses osi otra tea rt Ue ratas dtd is Uu 4 35 Resister DescripHOH o oues tino 4 35 RX2CS Command Status 177170 4 35 RX2DB Data Buffer Regist
8. COMMAND 4 56707 4564 vc 2524 815 LE SIIY 41812 6016777 4 5 RACS LUAU CUPMAND 91522 8824767 1842 FOR GD UTR vvi524 665767 Beda 181 Fle FIN FLAG 53 91214 2 PFGULALS ZEFG 51532 616777 g e53 44572 UC T ekKAUb LOAD wURD COUNT c1547 9404767 9 42 JEn TF FOR IR MOL U TR 1944 65767 ev952v 151 tis pit FINI FLAG 20155 BYE 2 PEGUALS ZERO 1552 012777 462744 984582 BRbUPF RXDE PTHEN LOAD BASE ADDR FOR INPUT BUFFER 7156 ogar ROP vvi5o2 90880267 1 2 75 JFETURN H w S9 DD 69 53 NO CD QE 69 SA dB GR 49 ccm momo gt 58711 ODYLF TP 1 TRANSFER READY S BROUTINE j P dO 99 CO Ua UO GR dp UD CO 99 CS CD gw 59 65 eS UD 66 ce 8 05 Bee ete me jl 902146 75757 9800476 TOC T YFPFSFT OUT 492152 032777 2920200 9790116 18 BIT 82 2 5 SFE IF TRANSFER PEACY SET 472160 4601263
9. 000 Buffer 001 Empty Buffer 010 Write Sector 011 Read Sector 100 Set Media Density 101 Read Status 110 Write Deleted Data Sector 111 Read Error Code The following paragraphs describe in detail the programming protocol associated with each function encoded and written into RX2CS bits 1 3 if Done 15 set 4 3 3 1 Fill Buffer 000 This function is used to fill the RX02 data buffer with the number of words of data specified by the RX2WC register Fill buffer is a complete function in itself the function ends when RX2WC overflows and if necessary the control has zero filled the remainder of the buffer The contents of the buffer may be written on the disk by means of a subsequent Write Sector command or returned to the host processor by an Empty Buffer command If the word count is too large the function is terminated Error and Done are asserted and the Word Count overflow bit is set in RX2ES To initiate this function the RX2CS is loaded with the function Bit 4 of the RX2CS Unit Select does not affect this function since no disk operation is involved Bit 8 Density must be properly selected since this determines the word count limit When the command has been loaded the Done bit RX2CS bit 5 goes false When the TR bit is asserted the RX2WC may be loaded into the data buffer register When TR is again asserted the RX2BA may be loaded into the RX2DB The data words are trans ferred directly from memory and when RX2WC over
10. Figure 4 11 RXSE Write Write Deleted Data Read Example Sheet 1 of 2 4 14 99 100 101 102 105 104 105 106 187 128 129 110 111 112 115 114 115 116 117 118 119 120 121 122 125 124 125 126 127 128 129 138 131 132 133 134 135 136 137 138 139 141 142 145 244 145 146 147 148 149 150 151 152 155 154 155 156 157 158 159 260 161 162 165 164 165 166 167 168 169 175 271 172 173 9248 2256 8246 5206 0247 7422 0250 6797 8251 2297 0252 5206 8253 7482 8254 7778 8255 0228 8256 920290 8257 2208 8268 90700 9261 590008 9262 02909 0263 2200 90264 vegg 8265 2200 Figure 4 11 CRC ERROR OCCURED AND TEST THe ERROR RETHY COUNTER PROGRAM LOCATION CTRY AND RETRY THE COMMAND UNTIL THE CRC ERROR RECOVERS JOR UNTIL THE CTRY COUNTER OVERFLOWS 158 CTRY JMP RETRY RETRY THE COMMAND HLT WARD CRE ERROR THE ERROR FLAG 15 5 THE ERROR 15 CNOT A PARITY ERROR AND IS A CRE ERROR THEREFORE 15 MUSY BE A SEEK ERROR CONTENTS OF THE TRANSFER REGISTER BITS 18 11 s 0 SEEK INIT 107 67X7 TO INITISLIAE INCREMENT AND TEST THE SEEK ERROR RETRY COUNTER PROGRAM LOCATION STRY RETRY THE COMMAND UNTIL THE SEEK ERROR RECOVERS JOR UNTIL THE CTRY COUNTER OVERFLOWS TO 158 STRY JMP RETRY RETRY THE COMMAND HLT WARD SEEK ERROR THE FOLLOWING PRO
11. 6701 1 72 LOAO THE COMMAND AC 18 THE COMMAND 5792 137 T3 1040 OR HEAD THE TRANSPER REGISTER T25 5705 1 2 SKIP ON TRANSFER REQUEST FLAG BERS 6728 7137 12 SKIP ON ERROR FLAG 80Ne 5795 7137 72 8x1 ON DONE FLAG INTRe 57295 AC 82 INTERRUPT ENABLE OFF AC s4 MEANS ON INIYs 6707 7137 TI INITIALIZE THE RX SUBSYSTEM FILLOWING IS A PROGRAMING EXAMPLE OF THE PROTOCOL REQUIRED yee 4RITE WRITE gELETEO O8 READ AT SECTOR S THE CONTENTS OF PROGRAM SECTOR OF TRACK T THE CONTENTS OF PROGRAM LOCATION TN B 03 12 HIDE egae START 4412 RETRY CONSTANT OCA Cray UP CRC COUNT 419 8797 SET UP SEEK RETRY COJNT wRITE WRITE DELETED ODATA 29 REA 50N AXE SURE DRIVE READY FOR US Jp aol NOT WAIT RETRY TAD 1258IT MODE 190 IF Be8TT MODE TaD FUNCUN GET FUNCTION CODE 28 GET DRIVE PARAMETERS UNIT 8 DENSITY DCA Co 44AND ENTTRE COMMAND GET COMMAND 7 350 COMMAND REGISTER GET COMMAND 5122 IT 8 817 YES SKIP AND DO 8 31 PROTOCOL 1F 12 DONE CLL RTL GET UPPER 4 8178 OF RTL WIRD TO LOwER RAL 4a BITS OF STR WwAIT FOR TRANSFER REQUEST LOOP UNTIL TR 6 SECON
12. 8812106 9091224 041232 081236 001242 91244 801252 1256 901262 681204 001212 276 001314 21322 801346 041332 81334 041342 021346 901352 801354 261362 801366 801372 21374 2014800 001402 21403 0057067 981841 294767 800240 816767 852167 456767 016777 004167 025767 881815 816777 0 4767 805767 0901885 816777 484767 06207 612757 856767 16777 674767 805767 6010424 816777 604767 95767 8921014 0127717 004767 985767 621004 95777 19080001 000207 881078 0981032 001026 060163 010460 0481052 001012 0081486 891876 v gd ie 61926 001060 86 10 6 762 o01v40 86082656 668730 0680752 98288722 006 716 4 6 07626 004736 2726 000776 CY UBL 008716 0v2342 908756 gloser 06675 geo 3oe Figure 4 31 eSBTIL MODULE 4 SUBRUUTINE J eo em 99 ah co co D 29 65 ER SAH 59 52 9 OA 40 da OD CD D CD 9 GR XO TST BNE JSR NOP MOV BIS 15 MOV JSn TST BNE 48 181 BNE ENDULT1 R18 FIN ENDOUI 2 UTI CMD 8165 Aalk kip ENDOU PC FIN ENDOUT TA 8HADDB 1 1 FIN
13. There are two error indications given by the RX8E system The read status function Paragraph 4 1 4 7 will assemble the current contents of the RXES Paragraph 4 1 3 6 which can be sampled to determine errors The read error register function Paragraph 4 1 4 9 can also be used to retrieve explicit error information The results of the read status function or the read error register function are in the interface register when Done sets indicating the completion of the function The XDR IOT must be issued to transfer the contents of the interface register to the PDP 8 s AC NOTE A read status function is not necessary if the DRV READY bit is not going to be interrogated because the RXES is in the interface register at the com pletion of every function 4 11 The error codes for the read error register function are presented below Octal Code Error Code Meaning 0010 Drive 0 failed to see home on Initialize 0020 Drive 1 failed to see home on Initialize 0030 Found home when stepping out 10 tracks for INIT 0040 Tried to access a track greater than 77 0050 Home was found before desired track was reached 0070 Desired sector could not be found after looking at 52 headers 2 revolutions 0110 More than 40 us and no SEP clock seen 0120 A preamble could not be found 0130 Preamble found but no I O mark found within allowable time span 0150 The header track address of a good header does not compare with the desired track 0160 Too
14. a Diskette wear a If worn replace Diskette mounting hole b If the hole is not concentric re place diskette Mismatch in recording density If diskette data densiiy is not on a diskette compatible with data to be re corded replace diskette with a new preformatted diskette 3 3 4 PROGRAMMING This chapter contains programming information for the following interface options RX8E RX28 RXVII RX211 and RXV21 The RX8E and RX28 programming information is presented followed by the and RXVI1 information and then the RX211 and RXV21 information is pre sented The RX8E and RXVII options are used for single density recording and are com patible with the RX01 Floppy Disk System The RX28E RX211 and RXV21 can be used for either single or double density recording 41 RX8E AND RX28 PROGRAMMING INFORMATION The RXSE interface allows two modes of data transfer 8 bit word length and 12 bit word length In the 12 bit mode 64 words are written in a diskette sector thus requiring 2 sectors to store page of information The diskette capacity in this mode is 128 128 12 bit words 1001 pages In the 8 bit transfer mode 128 8 bit words are written in each sector Disk capacity is 256 256 8 bit words which is a 33 percent increase in disk capacity over the 12 bit mode The 8 bit mode must be used for generating IBM compatible diskettes since 12 bit mode does not fully pack the sectors with data T
15. a single PDP 8 These multiple device codes are also shared with other devices Depending on what other devices are on the system the RX8E R X28 device code can be selected to avoid conflicts Refer to the PDP 8 Small Computer Handbook for specific device codes 4 The device codes selected by switches according to Table 4 1 These switches control ac bits 6 8 while ac bits 3 5 are fixed at 15 The device code is initially selected to be 70 Switches 7 and 8 are not connected and will not affect the device selection code The switches are all located on a single DIP switch package that is located on the M8357 RX8E RX28 interface board Table 4 1 Device Code Switch Selection 4 1 2 Instruction Set The RX8E RX28 instruction set is listed below and described in the following paragraphs When operating as an RX28 for the 8 bit mode all instruction set commands are transferred in two 8 bit bytes Mnemonic Description 67x0 No Operation 67 1 LCD Load Command Clear AC 67x2 XDR Transfer Data Register 67x3 STR Skip on Transfer Request Flag Clear Flag 67x4 SER Skip on Error Flag Clear Flag 67x5 SDN Skip on Done Flag Clear Flag 67x6 INTR Enable or Disable Disk Interrupts 67 7 Initialize Controller and Interface 4 1 2 1 RX8E Load Command LCD 67x1 This command transfers the contents of the AC to the interface register and clears the AC The RX02 begins to execute the
16. an Initialize 4 3 2 2 RX2DB Data Buffer Register 177172 This register serves as a general purpose data path between the 2 and the interface It may represent one of six 02 registers according to the protocol of the function in progress Paragraph 4 3 3 This register is read write if the 02 is not in the process of executing a command that is it may be manipulated without affecting the RX02 subsystem If the 2 is actively executing a command this register will only accept data if RX2CS bit 7 TR is set In addition valid data can only be read when TR 15 set CAUTION Violation of protocol in manipulation of this register may cause permanent data loss 4 36 4 3 2 3 RX2TA RX Track Address Figure 4 26 This register is loaded to indicate on which of the 114 0 7610 tracks a given function is to operate It can be addressed only under the protocol of the function in progress Paragraph 4 3 3 Bits 8 15 are unused and are ignored by the control 15 14 13 12 11 10 09 08 07 06 05 04 03 02 01 00 USED 0 114 Figure 4 26 RX2TA Format RX211 RXV21 4 3 2 4 25 RX Sector Address Figure 4 27 This register is loaded to indicate which of the 328 1 2610 sectors a given function is to operate It can be addressed only under the protocol of the function in progress Paragraph 4 3 3 NOT USED CP 1511 Figure 4 27 RX2SA Format RX211 RXV21 4 3 2 5 RX2WC RX Word Count
17. ay 9 CB EX CO XR XS db O3 dA 02 Co rx 9 59 US UO UD CD ra 941 06 24 46901 14 0416767 624 699626 MUY 011 JSELECT DRIVE v1416 52797 Steele 12 815 EIET ISET READ COMMAND INT ENB 1424 256767 976544 04224684 BIS PSET DENSITY 91432 815777 70906800 e0067V FOV C us RACS LUAD CUMMAND 881444 64767 JSh 160 11 READY 091444 016777 bleeds ROY SA RXDB LOAD SECIOF ADDRESS 401452 094767 0247 JSR IGU AWAIT TRANSFER READY 6481456 919777 wot 057 900546 T 8RXUH LOAD TRACK ADDRESS 071404 04767 wafla EC INTER FOR INTERRUPT 591470 C4767 2 2 PIHEN GET 2 SUFFER 2 1474 982047 ERLIAEY RTs RETURN jae Se 99 tO m ssa 09 em G9 sp UO 49 99 CO P 9 NP NS we OUR G as eSHTITL 2 2 EMPTY 2 BUFFER H 49 CO Gb EE 55 9 00 x QS GM r3 OR So 65 wx 55 59 SE CR 23 SBS OD TO xS 65 gt 6914758 012757 3 60532 INBUE ZI 3
18. 19 48 3cm 17 0 432cm 26 5 66 3cm SIDE VIEW NOTE DUST COVER ATTACHED TO CABINET NOT RX02 1825 Figure 2 1 02 Outline Dimensions 2 1 the 2 is mounted in a cabinet Figure 2 2 provision should be made for service clearances of approximately 56 cm 22 inches at the front ang rear of the cabinet so that the RX02 can be extended or the cabinet rear door opened SWINGING DOOR R H OR L H FRAME MOUNTING FRAME DOOR R H OR L H 16 eu 46 35 REMOVABLE END PANEL 48 3a0 122 47cm REMOVABLE END PANEL 3 0 gt 76 2cm PORTS CABLE ACCESS L CASTER LEVELER RADIUS 2 4 PLACES 6 12 cm p 4 CASTERS ri 24 t A 54 87 19 48 26 RX02 EXTENDED FROM CABINET CABINET 71 7 16 182 28 HIGH MA 1828 FLOOR LINE TO CABINET TOP Figure 2 2 Cabinet Layout Dimensions 2 1 2 Cabling The standard interface cable provided with an RX02 BCOSL 15 is 4 6 m 15 ft in length the position ing of the 02 in relation to the central processor should be planned to take this into consideration The R X02 should be placed near the control console or keyboard so that the operator will have easy access to load or unload disks The position immediately abo
19. 4 OD WIE RAO tench 1 5 Figure No E 1 DN tA Ww dx QN tA 4 4 2 4 4 4 5 4 6 4 7 4 8 4 9 4 10 4 11 4 12 4 13 4 14 4 15 4 16 4 17 4 18 4 19 4 20 4 21 4 22 4 23 4 24 4 25 4 26 4 27 4 28 4 29 4 30 4 31 4 32 FIGURES Cont Title Page Underside VIew ol a cese bid 1 6 Diskete Modia 1 9 Plux Reversal Patterns for 5 1 10 FM versus auti eid 1 11 Track Format Eac r Reed oo quina 1 12 Sector Format or EE 1 12 KX02O0uthne DIMENSIONS suce 2 Cabinet Layout Dimensions eben er d pret to 2 2 ELTE 2 3 RAO 2 7 02 Cabinet Mounting 51 0000 1 2 7 E MSSACMOGGITICAUOI 2 10 LCD Word Format RASE uus ir aS dtes itae 4 2 Command Word Formit 4 3 Command Register Format oi eire 4 4 Command Register 28 4 4 Error Code Register
20. AVE 28 50 PR 082162 9252687 20244 i C TACT TIME Sut 0952168 1371 Bre 13 YF NOT TIFED OTe BR 0921472 281 Nnp 922172 RTS 3 WP X NP NS VO CR 99 95 GR GP QD 00 CP 49 UM cS OD CP SP GO XR UO CX 9 CO Wo FD US JD UD aes OP awe MA 1852 Figure 4 32 RX21I RXV21 Read Empty Buffer Example 4 45 RX02 FLOPPY DISK SYSTEM Reader s Comments USER S GUIDE EK RX02 UG 001 Your comments and suggestions will help us in our continuous effort to improve the quality and usefulness of our publications What is your general reaction to this manual In your judgment is it complete accurate well organized well written etc Is it easy to use What features are most useful Does this manual satisfy the need you think it was intended to satisfy Does it satisfy your needs CW LT Please send me the current copy of the Technical Documentation Catalog which contains information on the remainder of DIGITAL s technical documentation Name Street Title City 1 1 State Country Department 1 1 Additional copies of this document are available from Digital Equipment Corporation 444 Whitney Street Northboro Ma 01532 Attention Communications Services NR2 M15 Customer Servi
21. FLAG INDICATE THE COMPLETION THE EMPTY BUFFER COMMAND a PRIOR TESTIN G THE ERROR FLAG j ELoop 7578 RXCS TEST TRANSFER REQUEST FLAG BMI EMPTY BNE IF TRANSFER REQUEST FLAG 15 SET 917 DONEBIT RXCS gt TEST FOR DONE FLAG BEQ ELOOP 8EQ UNTIL THE DONE FLAG SETS THE DONE FLAG IS SET iTEST FOR ANY ERRQRS ONLY ERROR POSSIBLE IS A PARITY ERROR TST RXCS BNE 1 HALT ERRORS e OK COMPLETE INCFEMENT AND TEST THE PARITY ERROR RETRY PROGRAM LOCATION RETRY THE CoMMAND UNTIL THE ERROR RECOVERS OR UNTIL THE PTRY CUNTER OVERFLOWS TO 15 INC PTRY BNE ESETUP RETRY To EMPTY THE SECTOR BUFFER HALT HARD PARITY ERROR THE TRANSFER REQUEST FLAG IS SEY TRANSFER DATA To THE PROGRAM DATA BUFFER FROM THE 81 SECTOR BUFFER EMPTY MoVB RXDB KB BR ELOOP ITHE FOLLOWING 3 PROGHAM LOCATIONS ARE THE ERROR RETRY COUNTERS PTRY g ERROR RETRY COUNTER CTRY 8 ERROR RETRY COUNTER STRY 2 ERROR RETRY COUNTER i PROGRAM LOCATION COMMAND CONTAINS THE COMMAND To BE ISSUED VIA THE LCO 107 WRITE 4 WRITE DELETED DATA 44 OR READ 6 OR EMPTY BUFFER 2 COMMANDS 8 8 44 6 2 5 GO BIT 4 1 i PROGRAM LOCATION SECTOR CONTAINS TH SECTOR ADDRESS 1 TO 32 SECTOR 8 1 0 32 PROGRAM LOCATION TRACK CONTAINS THE TRACK ADDRESS 8 114 OCTAL TRACK 2 9 70114 PROGRAM EQU
22. OR CRC ener MODIFIED DATA SYNC FIELD 6 BYTESO S ID ADDRESS MARK TRACK ADDRESS 1 BYTE SECTOR ADDRESS MARK 1 BYTE DATA MARK SYNC FIELD 6 BYTES 05 DATA OR DELETED DATA FOR WRITE OF NEXT ROTATION DATA FIELD Figure 1 10 Sector Format Each Sector 128 BYTES OF FM 256 0 BYTES OF L 6 BYTES ID GAP WRITE GATE TURN OFF 15 OR 05 WRITE GATE TURN FOR WRITE OF PRECEEDING DATA FIELD 2 BYTES 1827 Header Field Description The header field is broken into seven bytes eight bits byte of information and 15 preceded by a field of at least six bytes of zeros for synchronization The header and its preamble are always recorded in FM Byte No 3 Zeros 1 12 Byte 1 Address Mark This is a unique stream of flux reversals not a string of data bits that is decoded by the controller to identify the beginning of the header field Data FE hex clock C7 hex Byte 2 Track Address This is the absolute 1148 binary track address Each sector contains track address information to identify its location on of the 77 tracks 3 Byte 4 Sector Address This is the absolute binary sector address 1 324 Each sector contains sector address information to identify its circumferential position on a track There is no sector 0 Byte 5 Zeros Bytes No 6 and 7 CRC This is the cyclic redundancy check character that is calculated for
23. Recording Only RX8E RX11 RAVE ashen HQ 1 7 PDPS since rod dolum phate bea aus ditto tuU iei 1 7 PO Pl Opera OI EE EUM 1 7 ESISELODEFAL OA sep rox ides 7 Operation For Single or Double Density Recording RX28 pm Er 1 7 PDP S ns serius ed etia cto iu Rica nace 1 7 deu ero 1 7 1 7 esate cee 1 7 ope rt br REPE 1 9 Media 1 9 Recording Scheme 1 10 Double Prequency E M 1 10 Miller Code CME IM s i oo E de bc a a 1 10 Lopical Forma M 1 12 Header Field Descrip uem mon optem tria tees tice audes Deus ah b d 1 12 Data Field DeseriDHOH s ues dons RU debui ebbe et mua TO 1 13 Track emot dat 1 13 CRC Capability acp ated 1 13 INSTALLATION SITE PREPARATION ER 2 1 2 1 ____ 2 2 ACH A eae Eos 2 2 Power Require melts uova pu revisa ende Us 2 2 ili 224 32
24. Register Figure 4 28 For a double density sector the maximum word count is 12810 For a single density sector the maximum word count is 6410 If a word count is beyond the limit for the density indicated the control asserts Word Count Overflow bit 10 of RX2ES This is a write only register The actual word count and not the 2 s complement of the word count 15 loaded into the register Q2 01 Figure 4 28 RX2WC Format RX211 RXV21 4 3 2 6 RX2BA RX Bus Address Register Figure 4 29 This register specifies the bus address of data transferred during fill buffer empty buffer and read definitive error operations Incrementation takes place after a memory transaction has occurred The RX2BA therefore is loaded with the ad dress of the first data word to be transferred This is a 16 bit write only register Paragraph 4 3 3 11 2 12 10 Figure 4 29 RX2BA and RX2DB Format RX211 RXV21 4 3 2 7 RX2DB Data Buffer Figure 4 29 All information transferred to and from the floppy media passes through this register and is addressable only under the protocol of the function in prog ress Paragraph 4 3 3 4 37 4 3 2 8 RX2ES RX Error and Status Figure 4 30 This register contains the current error and status conditions of the drive selected by bit 4 Unit Select of the RX2CS This read only register can be addressed only under the protocol of the function in progress Paragraph 4 3 3 The RX2ES 15 loc
25. Sectors per track Recording technique Bit density maximum on inner track Track density Average access Environmental Characteristics Temperature RX02 operating 02 nonoperating Media nonoperating 6 ms track maximum 25 ms maximum 360 rpm 2 5 166 ms rev nominal 1 77 0 76 0 114 26 1 26 or 0 328 Double frequency or modified 3200 bpi FM or modified MFM 48 tracks inch 262 ms computed as follows Seek Settle 77 58 3 X 6ms 25 ms Rotate 166 ms 2 262 ms 15 to 32 C 59 to 90 F ambient maximum temperature gradient 11 C hr 20 F hr 359 to 60 30 to 140 359 to 52 30 to 125 NOTE Media temperature must be within operating temper ature range before use Heat Dissipation R X02 System Relative humidity 02 operating Less than 225 Btu hr 25 77 F maximum wet bulb 2 C 36 F minimum dew point 20 to 80 relative humidity 1 8 RX02 nonoperating 5 to 98 relative humidity no condensation Media nonoperating 10 to 80 relative humidity Magnetic field Media exposed to a magnetic field strength of 50 oersteds or greater may lose data Interface modules Operating temperature 5 to 50 41 to 122 Relative humidity 10 to 90 Maximum wet bulb 32 C 90 F Minimum dew point 29 36 Electrical Power consumption RX02 5 at 5 Vdc 25 W 0 14 A at 5 Vdc 0
26. The Drv Den bit indicates whether the mark was a single or double density deleted data address mark The data follow ing the mark will be collected and transferred normally as the deleted data mark has no further significance other than to establish drive density Any alteration of files or actual deletion of data due to this mark must be accomplished by user software Drive Ready This bit indicates that the selected drive is ready if bit 7 1 and all conditions for disk operation are satisfied such as door closed power okay diskette up to speed etc The RX02 may be presumed to be ready to perform any operation This bit is only valid when retrieved via a read status function or initialize Unit Select This bit indicates that drive O is selected if bit 820 This bit indicates the drive that is currently selected Word Count Overflow This bit indicates that the word count is beyond sector size The fill or empty buffer operation is terminated and Error and Done are set Nonexistent Memory Error This bit is set by the interface when a DMA transfer is being performed and the memory address specified in RX2BA is nonexistent 4 38 4 3 3 Function Codes Following the strict protocol of the individual function data storage and recovery on the RX211 RXV21 occur with careful manipulation of the RX2CS and RX2DB registers The penalty for violation of protocol can be permanent data loss A summary of the function codes is presented below
27. This register is loaded to indicate on which of the 26 32g sectors a given function is to operate It can be addressed only under the protocol of the function in progress Paragraph 4 2 3 Bits 8 15 are unused and are ignored by the control 15 14 13 12 11 10 09 08 07 06 05 04 03 02 01 00 NOT USED 1 32 1511 Figure 4 19 RXSA Format RXII RXVI1 4 2 2 5 RXDB RX Data Buffer Figure 4 20 All information transferred to and from the floppy media passes through this register and is addressable only under the protocol of the function in prog ress Paragraph 4 2 3 MA 1866 Figure 4 20 RXDB Format RX11 RXVI11 4 25 4 2 2 6 RXES RX Error and Status Figure 4 21 This register contains the current error and status conditions of the drive selected by bit 4 Unit Select of the RXCS This read only register can be addressed only under the protocol of the function in progress Paragraph 4 2 3 The RXES content is located in the RXDB upon completion of a function 15 14 13 12 11 10 09 08 07 06 05 04 03 02 01 00 EEG SEE ie Lodo Bla PN NOT USED SEL 1867 Figure 4 21 RXES Format RXVI1 RXES bit assignments are Bit No 0 Description CRC Error cyclic redundancy check error was detected as information was retrieved from a data field of the diskette The RXES is moved to the RXDB and Error and Do
28. V7 W6 Installed V8 W7 Removed Installed SW2 OFF SW3 ON SW4 ON SWS5 OFF SW6 ON SW7 OFF SW2 OFF A4 W10 Removed SW1 OFF A3 W9 Removed Vector Address 264 Selectable V2 Installed Hardwired V 3 Removed A 3 Installed V 4 Installed 4 Installed V 5 Installed Installed V 6 Removed Installed V 7 Installed V 8 Removed Vector Address Register Address 06 CPU Selectable NE nstalled W 8 A 3 Removed W 9 A 4 Removed W 10 A 5 Removed W 11 A 6 Removed W 12 A 7 Installed W 13 A 8 installed W 14 A 9 Removed W 15 A 10 Removed vs 16 11 Removed dig 12 Removed W UY 2 2 Removed W 2 V 3 Installed W 3 V 4 Removed W 4 V 5 Removed W 5 V 6 Installed 5 W 6 V 7 Removed 6 7 Removed A 8 Removed A 9 Installed 10 Installed A 11 Installed A 12 Installed Standard 2 9 2 51 PDP8 A Modification In order to bootload from 02 on PDP8 A system it is necessary to modify the KM8 A M8317 extended option module if present as follows Figure 2 6 replace E82 with prom 23 465A2 e replace E87 with prom 23 469A2 e set SW 1 SW 2 according to bootload device as shown below Program 52 5 52 6 52 7 52 8 81 1 51 2 51 3 H L ON ON ON OFF ON ON ON RK8 E ON OFF ON OFF ON OFF ON RX8 E ON OFF OFF ON OFF ON ON RL8A OFF ON OF
29. a Read Status function or for drive 0 upon com pletion of an Initialize NOTE 2 If the error bit was set in the RX2CS but error bits are not set in the RXES specific error conditions can be accessed via a read error register function 4 1 3 7 RX28 RX Error and Status Figure 4 10 The RX2ES contains the current error and status conditions of the selected drive This read only register can be accessed by the read status function 101 The RX2ES is also available in the interface register upon completion of any function The RX2ES is accessed by the instruction The meaning of the error bits is given below 00 01 02 03 04 05 6 07 08 09 10 11 _ fere rey eee RESERVED NOT USED RX02 MA 1862 Figure 4 10 RX2ES Format RX28 Bit No Description 11 CRC Error The cyclic redundancy check at the end of the data field has indicated an error The data must be considered invalid it is suggested that the data transfer be retried up to 10 times as most data errors are recoverable soft 10 Reserved 9 Initialize Done This bit indicates completion of the Initialize routine It can be asserted due to 02 power failure system power failure or programmable or bus Initialize This bit is not available within the RX2ES from a read status function 4 7 Description RX02 This bit is asserted if an 2 system is being used DEN ERR This bit indicates that the density of the function
30. a power loss has been detected by the RX02 However write sector will be accepted as a valid in struction and the random contents of the buffer will be written followed by a valid CRC NOTE The contents of the sector buffer are not destroyed during a write sector operation 4 3 3 4 Read Sector 011 This function is used to locate the desired sector and transfer the contents of the data field to the internal buffer in the control This function may also be used to retrieve rapidly 5 ms the current status of the drive selected The initiation of this function clears RX2ES TR and Done When TR is asserted the program must load the desired sector address into the RX2DB which will drop TR When TR is again asserted the program must load the desired track address into the RX2DB which will drop TR TR and Done will remain negated while the RX02 attempts to locate the desired sector If the RX02 is unable to locate the desired sector within two diskette revolutions for any reason the RXV21 RX211 will abort the operation set Done and Error bit 15 RX2CS move the contents of the RX2ES to the RX2DB and if bit 6 RX2CS Interrupt Enable is set initiate an interrupt If the desired sector is successfully located the control reads the data address mark and determines the density of the diskette If the diskette drive density does not agree with the function density the operation is terminated and Done and Error bit 15 RX2CS are asser
31. abra sive airborne particles NOTE Removable media involve use handling and mainte nance which are beyond DIGITAL s direct control DIGITAL disclaims responsibility for performance of the equipment when operated with media not meeting DIGITAL specifications or with media not maintained in accordance with procedures approved by DIGITAL DIGITAL shall not be liable for dam ages to the equipment or to media resulting from such operation 2 4 UNPACKING AND INSPECTION 2 4 1 General The RX02 Floppy Disk System can be shipped in a cabinet as an integral part of a system or in a separate container If the 02 is shipped in a cabinet the cabinet should be positioned 0 5 final installation location before proceeding with the installation 2 5 2 4 2 Tools Installation of 02 Floppy Disk System requires no special tools or equipment Normal hand tools are all that are necessary However a forklift truck or pallet handling equipment may be needed for receiving and installing a cabinet mounted system 2 4 3 Unpacking 2 4 3 1 2 2 4 3 2 Cabinet Mounted Remove the protective covering over the cabinet Remove the restraint on the rear door latch and open the door Carefully roll the cabinet off the pallet if a forklift is available it should be used to lift and move the cabinet Remove the shipping restraint from the 02 and save it for possible reuse Slide the 02 out on the chassis slides and v
32. bit bytes of data PDP 8 PDP 11 LSI 11 or 256K 12 bit words PDP 8 can be stored and retrieved For each drive system using single density recording up to 256K 8 bit bytes of data or 128K 12 bit words PDP 8 can be stored and retrieved The R X02 interfaces with IBM compatible devices when single density data recording is used For single or double density recording the R X02 is used with either an M8357 interface module PDP 8 an M8256 interface module PDP 11 or an M8029 interface module LSI 11 The interface mod ules convert the RX02 I O bus to the bus structure of the computer being used Each module controls the interrupts to the CPU initiated by the RX02 and handles the data interchange between the RX02 and the host computer Each interface module is powered by the host processor In addition the RX02 is used for single density recording when it is configured to be compatible with the RXOI The interface module used is either an M8357 PDP 8 an M7846 PDP 11 or an M7946 LSI 11 To record or retrieve data the RX02 performs implied seeks Given an absolute sector address the RX02 locates the desired sector and performs the indicated function including automatic head posi tion verification and hardware calculation and verification of the cyclic redundancy check CRC character The CRC character that is read and generated is compatible with IBM 3740 equipment 1 2 GENERAL DESCRIPTION An 02 Floppy Disk System consists
33. by an initialize to the 02 4 1 3 3 2 RX Track Address Figure 4 6 This register is loaded to indicate on which of the 77 0 76 tracks a given function is to operate It can be addressed only under the protocol of the function in progress Paragraph 4 1 4 Bits 0 3 are unused and are ignored by the control 4 1 3 4 RX2SA RX Sector Address Figure 4 7 This register is loaded to indicate on which of the 26 1 26 sectors a given function is to operate It can be addressed only under the protocol of the function in progress Paragraph 4 1 4 Bits 0 3 are unused and are ignored by the control 4 1 3 5 RX2ZDB RX Data Buffer Figure 4 8 All information transferred to and from the floppy media passes through this register and is addressable only under the protocol of the function in prog ress The length of data transfer is either 8 or 12 bits depending on the state of bit 5 of the command register when the Load Command IOT is issued Paragraph 4 1 3 1 4 1 3 6 RXSE RX Error and Status Figure 4 9 The RXES contains the current error and status conditions of the selected drive This read only register can be accessed by the read status function 101 The RXES is also available in the interface register upon completion of any function The RXES is accessed by the XDR instruction The meaning of the error bits is given below 00 01 02 NOT 0 114 NOT USED 1 32 USED 1858 1859 Figure 4 6 RX2TA Format RX
34. each sector from the first five header bytes using the IBM 3740 polynomial 1 5 3 2 Data Field Description The data field contains either 12110 or 25910 bytes of information depending on the recording scheme This field is preceded by a field of zeros for synchronization and the header field Figure 1 10 1 5 3 3 Byte 1 Data or Deleted Data Address mark This byte is always recorded in FM and is unique because it contains missing clocks It is decoded by the controller to identify the beginning of a data field The deleted data mark is not used during normal operation but the R X02 can identify and write deleted data marks under program control as required There is a unique address mark for each density as shown in the following table One of these marks is the first byte of each data field Table 1 1 Data Address Mark Code Hex Byte Density mod Bytes 2 129 FM or 257 modified This is the data field and it be recorded in either MFM modified It is used to store 12810 or 25610 depending upon encoding 8 bit bytes of information NOTE Partial data fields are not recorded Bytes No 130 and 131 or 258 and 259 These bytes comprise the CRC character that is calculated for each sector from the first 129 or 257 data field bytes using the industry stand ard polynomial division algorithm designed to detect the types of failures most likely to
35. for the RX8E is presented below When performing the following sequence of instructions interrupts must be off SKP JMP SDN JMP done or empty buffer If interrupts are not off the following sequence of events will occur Assume interrupts are enabled and the issues an interrupt request just before the SDN instruction the SDN instruction will be executed as the last legal instruction before the processor takes over However since the done flag is cleared by the SDN instruction the processor will not find the device that issued the interrupt The program must issue an SER instruction to test for errors following an SDN instruction For maximum data throughput for consecutive writes or reads in 8 bit mode interleave every three sectors in 12 bit mode interleave every two sectors This of course depends on program overhead When issuing the IOT XDR at the end of a function to test the status the instruction AND 377 must be given because the most significant bits 0 3 contain part of the previous com mand word If an error occurs and the program executes a read error register function 111 Paragraph 4 1 4 9 a parity error may occur for that command The error code coming back would not be for the original error in which the read error register function was issued but for the parity error resulting from the read error register function Therefore check for parity error with the read status func
36. implementing an empty buffer function with interrupts turned off IOF The first instruction sets the number of retries at 10 A 215 set in the AC to indicate an Empty Buffer command and the command is loaded When is set the program jumps to EMPTY to transfer a word to the BUFFER location A jump is made back to loop to wait for another TR This process continues until either 64 words or 128 bytes have been emptied from the sector buffer When Done is set the program tests to see if the error bit is set If the error bit 15 set the program retries 10 times If the error persists a hard parity error is assumed indicating a problem in the interface cable 4 1 6 3 Buffer Function Figure 4 13 presents a program to implement a fill buffer function It is very similar to the empty buffer example 4 13 Ul GU GN E 82228 0221 0222 0225 0224 8205 0226 0227 82 2 0211 0212 2213 8214 8213 2216 0217 8220 8221 0222 0223 8224 2225 0226 8227 8238 2231 2232 2233 9234 8235 8236 8237 2242 8241 0242 0253 8244 8701 6702 6703 6704 6795 6786 6787 1254 3255 1254 3256 1254 3257 1268 1261 1262 8701 6723 5212 1263 6782 7200 5795 5217 1264 6722 7288 6785 5224 6784 7482 6702 3265 7395 2265 7538 5241 2255 5286 7822 7301 2265 7650 5252 PROGRAMMING EXAMPLES FOR THE RXB RXO1 FLEXIBLE DISKETTE THE FOLLOWING ARE RX21 107 CODE DEFINITI
37. is initiated This bit is cleared by Initialize and is a read write bit Transfer Request This bit signifies that the RX211 RXV21 needs data or has data avail able This is a read only bit Density This bit determines the density of the function to be executed This bit is readable only when Done is set at which time it indicates the density of the function previously executed This is a read write bit Reserved for future use Must be written as a zero RXO2 This bit is set by the interface to inform the programmer that this is an 02 system This is a read only bit Extended address These bits are used to declare an extended bus address These are write only bits RX211 RXV21 Initialize This bit is set by the program to initialize the RX211 RXV21 without initializing all devices on the Unibus This is a write only bit CAUTION Loading the lower byte of the RX2CS will also load the upper byte of the RX2CS Upon setting this bit in the RX2CS the RX211 RXV21 will negate Done and move the head position mechanism of both drives if two are available to track 0 Upon completion of a successful Initialize the RX02 will zero the error and status register and set Initialize Done It will also read sector 1 of track 1 on drive 0 into the buffer Error This bit is set by the RX02 to indicate that an error has occurred during an attempt to execute a command This read only bit is cleared by the initiation of a new command or
38. must load the desired track address into the RX DB which will negate TR If the desired track is not found the RX11 RXV11 will abort the operation move the contents of the RXES to the RXDB set RXCS bit 15 Error assert Done and initiate an interrupt if RXCS bit 6 Interrupt Enable is set TR will remain negated while the RX02 attempts to locate the desired sector If the RX02 is unable to locate the desired sector within two diskette revolutions the RX11 RXV11 will abort the operation move the contents of the RXES to the RXDB set RXCS bit 15 Error assert Done and initiate an interrupt if RXCS bit 6 Interrupt Enable is set If the desired sector is successfully located the RX11 RXVI1 will write the 128 bytes stored in the internal buffer followed by a 16 bit CRC character that is automatically calculated by the RX02 The RX11 RXV11 ends the function by asserting Done and initiating an interrupt if RXCS bit 6 Interrupt Enable is set NOTE 1 The contents of the sector buffer are not valid data after a power loss has been detected by the RX02 The write sector function however will be accepted as a valid function and the random contents of the buffer will be written followed by a valid CRC NOTE 2 The write sector function does not destroy the con tents of the sector buffer 4 2 3 4 Read Sector 011 This function is used to locate a desired track and sector and transfer the contents of the data field to the CPU contro
39. occur in recording on the floppy media These bytes will be recorded with the same encoding scheme as the data field Track Usage In the 3740 system some tracks are commonly designated for special purposes such as error information directories spares or unused tracks 2 is capable of recreating any system structure through the use of special systems programs but normal operation will make use of all the available tracks as data tracks Any special file structures must be accomplished through user software 1 5 3 4 Capability Each sector has a two byte header CRC character and a two byte data CRC character to ensure data integrity The CRC characters are generated by the hardware during a write operation and checked to ensure all bits were read correctly during a read operation The CRC character is the same as that used in IBM 3740 series equipment 1 13 INSTALLATI This chapter contains information that is required for site preparation unpacking installation and testing of the RX02 Floppy Disk System Information is also provided to identify the various system configurations that are available 2 4 SITE PREPARATION 2 1 1 Space The RX02 is a cabinet mountable unit that may be installed in a standard Digital Equipment Corpo ration cabinet This rack mountable version is approximately 28 cm high 10 1 2 inches 48 cm wide 19 inches and 42 cm deep 16 1 2 inches as shown in Figure 2 1
40. of the diskette The carton should be retained if it is intact for storage of the diskette or for future shipping 3 2 3 3 OPERATING INSTRUCTIONS NOTE The left drive is always identified as drive 0 The 02 has no operator controls and indicators The diskette is inserted on a drive after com pressing the latch to allow the spring loaded front cover to open Place the diskette with the label or top up the jacket seams are on the bottom on the drive spindle Close the front cover which will automatically lock when it is pushed down Initialize the system from the computer and listen for audible clicking sounds which indicate the head is moving over the diskette the R X02 is ready for use Data storage and retrieval is controlled by the user s program CAUTION Do not open the drive door while the diskette is in use this results in errors 3 4 OPERATOR TROUBLESHOOTING Table 3 1 is a list of possible problems and some probable causes the operator may encounter If the problem cannot be corrected refer to the RX02 Floppy Disk System Technical Manual if available Table 3 1 Operator Troubleshooting Guide Problem Probable Cause Correction No power a Power cord disconnected a Connect power cord drive inoperative b Blown fuse b Replace fuse Circuit breaker open Close circuit breaker Drive not ready Drive door open a Close door Diskette improperly installed 5 Properly seat diskette Error in recording
41. of the following components M7744 Controller Module M7745 Read Write Electronics Module 771 D Power Supply RX02 CA Floppy Disk Drive 60 Hz max of 2 RX02 CC Floppy Disk Drive 50 Hz max of 2 One interface module is used M8357 PDP 8 Programmed I O M7846 PDP 11 Programmed I O M8256 PDP 11 with DMA M7946 LSI 11 Programmed I O M8029 1 51 11 with DMA All components except the interface modules are housed in 10 1 2 inch rack mountable box power supply M7744 module and M7745 module are mounted above the drives Interconnection from the 2 to the interface is with a 40 conductor BCOSL 15 cable of standard length 15 ft Figure 1 1 is a configuration drawing of the system part A shows the configuration for a bus interface with DMA part B shows the configuration for all Omnibus interfaces programmed 1 0 part shows the configuration for a bus interface programmed I O that is compatible Figure 1 2 is front view of a dual drive system 1 2 1 Interface Modules The interface modules plug into a slot on the bus for PDP 8 PDP 11 and LSI 11 computers Figure 1 3 shows the outline of the various modules and areas of interest on each module 1 2 ELECTRONICS 1 7745 READ WRITE ELECTRONICS ELECTRONICS 1 M7745 C BUS INTERFACE PROGRAMMED 1 0 RX01 COMPATIBLE A SWITCH ON THIS MOD 8029 BUS INTERFACE DISKETTE 1A 7015 580 BCO5L 15
42. or bent plugs Also be sure the fuse is not damaged 3 Visually inspect the interior of the unit for damaged wires or loose hardware 4 Loosen the screws securing hinged upper module M7744 and raise the module so modules M7744 and M7745 can be inspected for damaged components or wires 5 Verify that the items listed on the shipping order are included in the shipment Be sure the interface cable BCOSL 15 and the appropriate interface module are included NOTE If any shipping damage is found the customer should be notified at this time so he can contact the carrier and record the information on the acceptance form INSTALLATION 1 Ensure that power for the system is off 2 Loosen the screws securing the upper module M7744 and swing it up on the hinge 3 Inspect the wiring and connectors for proper routing and ensure that they are seated cor rectly 4 This step is for 50 Hz versions only Check the power configuration to ensure that the proper jumpers and the correct circuit breaker are installed Figure 2 3 5 Connect the BCOSL 15 cable to the M7744 module and route it along the near side of the chassis through the back of the RX02 to the CPU then connect it to the interface module for the PDP 8 PDP 11 LSI 11 The cable is connected to the M7744 module with the red stripe on the left looking from the component side of board the cable is connected to the interface module with the red stripe toward the cent
43. 1 4 3 4 1 4 4 4 1 4 5 4 1 4 6 4 1 4 7 4 1 4 8 4 1 4 9 4 1 4 10 4 1 5 4 1 5 1 4 1 5 2 4 1 6 4 1 6 1 4 1 6 2 4 1 6 3 4 1 7 4 1 8 4 2 4 2 1 4 2 2 4 2 2 1 4 2 2 2 4 2 2 3 4 2 2 4 4 2 2 5 4 2 2 6 4 2 3 4 2 3 1 4 2 3 2 4 2 3 3 4 2 3 4 4 2 3 5 4 2 3 6 4 2 3 7 CONTENTS Cont Page Register Descrip On 4 4 Command Repite TTL 4 4 Error ode T 4 5 4 6 RX2SA RX Sector Address icta er onte exe 4 6 RAZDB Data vet or iupra eor 4 6 RX8E RX Error and Status odisse mE 4 6 RX28 RX Error and depo due en lat 4 7 Punction Description oe I een tesi Das tn 4 8 Pall Buiter 000 4 9 Bulter 0OL xu 4 9 Write Sector OTO centies tore bbb 4 9 Read Sector tetro accosted a bt ule usa 4 10 Set Media Density 100 for RX28 4 10 Maintenance Read Status 101 for RX28 4 10 Read Status 101 for 4 4 10 Write Deleted Data Sector 110 uie be eden cese 4 11 Read Error Code Function 111 iuis o Eb 4 11 POWELL T
44. 111 must be loaded into the RX2DB to complete the protocol This extra character is a safeguard against an error in loading the command When the control recognizes this character it begins executing the command The control starts at sector 1 track 0 and reads the header information then starts a write operation If the header information is damaged the control will abort the operation If the operation is successfully completed Done is set and if bit 6 RX2CS Interrupt Enable is set an interrupt is initiated CAUTION This operation takes about 15 seconds and should not be interrupted If for any reason the operation is in terrupted an illegal diskette has been generated which may have data marks of both densities This diskette should again be completely reformatted 4 3 36 Maintenance Read Status 101 This function is initiated by loading the RX2CS with the command Done is cleared The Drive Ready bit bit 7 RX2ES is updated by counting index pulses in the control The Drive Density is updated by loading the head of the selected drive and reading the first data mark The RX2ES is moved into the RX2DB The RX2CS may be sampled when Done bit 5 RX2CS is again asserted and if bit RX2CS Interrupt Enable 15 set an interrupt will occur This operation requires approximately 250 ms to complete 4 3 37 Write Sector with Deleted Data 110 This operation is identical to function 010 write sector with the exception that a deleted da
45. 117 118 119 120 121 182 123 124 125 126 127 128 129 132 151 13e 133 134 135 136 137 138 139 142 131 142 194 184 145 146 147 188 149 158 154 182 153 154 155 155 157 156 159 161 162 163 164 165 166 16 158 169 17 2255 2256 9257 agba 0251 26 amp 2 9253 2055 debe 6657 2272 271 2172 2275 2274 2275 227 4277 2177 321 1327 7312 3321 7442 74292 5727 2271 522 7522 1772 8122 2224 3222 5782 2222 2222 2722 2222 THE E3ROR WAS NIT CRE 853 FOR WRUNG DENSITY IF DENSITY ERROR 0265 EXIST THEN WALT THIS ERRIR OCCURS IT COULD HAVE BEEN 3ECAUSE FIRGOT TO SET THE RIGHT NENSITY IN THE COMMAND woR 0 COULD THE WRONG 715 MAS REEN INSERTED THE DRIVE OR BE SOME OTMER REASIN BUT WE KNOW WHAT CAUSED IT WE PROCEED OENSYT CLA CLL RYL s RTR 20 ASK FOR DENSITY EKOR AND 5 JIN STATUS WORD IF SET SKIP 874 18 NOT DENSITY ERROR 4 87 SEEK ERROR HLT WITH OENSITY ERROR 817 SET IN EAROR MUST BEEN SEEK ERROR 4E GOT THIS FAR 195JE AN TNITIALTZE DRIVE 30 START FROM TRACK TY SEEK INIT TO INITIALIZE Rx 132 3TRY KEEP COUNT SEEK E
46. 2 1 4 2b 2 3 2 3 1 2 30 233 2 34 2 3 5 24 2 4 1 242 2 4 3 2 4 3 1 2 4 3 2 2 4 3 3 2 5 2 5 1 2 6 CHAPTER 3 3 1 3 2 2 051 2252 32 2 1 22 252 3 2 3 3 3 3 4 4 4 1 4 1 1 4 1 2 4 1 2 1 4 1 2 2 4 1 2 3 4 1 2 4 4 1 2 5 4 1 2 6 4 1 2 7 4 1 2 8 CONTENTS Cont Page Input Power Modification 2 3 Safely Precautions E a dat aiat 2 3 CONFIGURATION GUIDELINES RM 2 3 ENVIRONMENTAL CONSIDERATIONS eee 2 4 er ee 2 4 Temperature Relative ode o emi 2 4 Heat DISSI 2 5 Radiated Emn 2 5 BRUN 2 5 UNPACKING AN D INSPEC qua duas 2 5 2 5 2 6 Unpack M 2 6 2 6 Separate tg daar 2 6 PSCC 2 amp INSTALLATION IR 2 8 et
47. 29 31e 311 31e 8345 0386 0367 2358 935 8552 0353 0354 8335 8356 9357 9300 0351 9559 90353 9354 0355 2396 0367 8379 83 1 8372 0373 2376 2377 8431 8429 842 2925 2886 2427 241 2812 9413 8814 2576 8577 639 1266 3272 1577 5212 1275 1974 1275 327 1275 5721 1276 3297 7652 5778 1276 7136 7225 7224 5723 5367 5722 7288 5775 2420 2577 34239 5723 1412 5212 5725 5228 5724 7482 2777 577 7322 6732 3412 5228 8387 date 2522 2363 1238 THE FOLLOWING 19 A PROGRAMMING EXAMPLE OF PROTOCOL REQUIRED 70 THE SECTOR BUFFER EENTRY 412 8 TRYS TO EMPTY THE SECTOR ETRY ERROR RETRY COUNTER BUFPgRs1 PROGRAMS DATA BUFFER A19 INDEX REGISTER 0 MODE 8 JF 12e81T 190 IF 8 BIT FUNCUN 7 9 MEANS BUFFER ORIVEP DENSITY DCA COMMAND STORE ASSEMBLED COMMAND tco 135 COMMAND TO RX SAVED COMMAND AND 432 MASK FOR 86817 MODE 8817 MODE SET 00 Ge4NDE PROTOCOL ELOOP 129 1 MODE GO STRAIGAT TO EMPTY LOOP Tab COMMAND GET SAVED COMMAND CLL RTL GET 4 58 3 BITS 8 1 2 3 OF RTL CJMMANDO WORD JONN TO THE RAL 74 63878 8173 8 9 18 11 OF 578 7197 TO SKIP ON TRANSFER RE
48. 2CS normally assigned bus address 177170 and the data buffer register RX2DB normally assigned bus address 177172 The vector address is 264 4 3 2 Register Description 4 3 2 1 2 5 Command and Status 177170 Loading this register while the 02 is not busy and with bit O 1 will initiate a function as described below and indicated in Figure 4 25 15 14 3 12 11 10 DONE MA 1906 Figure 4 25 RX2CS Format 211 2 Bit No Description 0 Go Initiates a command to 02 This is a write only bit 1 3 Function Select These bits code of the eight possible functions described in Paragraph 4 3 3 and listed below These write only bits Code Function 000 Fill Buffer 001 Empty Buffer O10 Write Sector 01 Read Sector 100 Set Media Density 101 Read Status 110 Write Deleted Data Sector 111 Read Error Code 4 Unit select This bit selects of the two possible disks for execution of the desired function This bit is readable only when Done is set at which time it indicates the unit previously selected This is a read write bit 4 35 Done This bit indicates the completion of a function Done will generate an interrupt when asserted if Interrupt Enable RX2CS bit 6 is set This is a read only bit Interrupt Enable This bit is set by the program to enable an interrupt when the 02 has completed an operation Done The condition of this bit is normally determined at the time a function
49. 3 3 6 will assemble the current contents of the RX2ES which can be sampled to determine errors The read error code function Paragraph 4 3 3 8 can also be retrieved for explicit error information The RX211 RXV21 interface register can be interrogated to determine the type of failure that occurred The error codes and their meaning are listed below Octal Code Error Code Meaning 0010 Drive 0 failed to see home on Initialize 0020 Drive 1 failed to see home on Initialize 0040 Tried to access a track greater than 76 0050 Home was found before desired track was reached 0070 Desired sector could not be found after looking at 52 headers 2 revolutions 0110 More than 40 us and no SEP clock seen 0120 A preamble could not be found 0130 Preamble found but no ID mark found within allowable time span 0150 The header track address of a good header does not compare with the desired track 0160 Too many tries for an IDAM identifies header 0170 Data AM not found in allotted time 0200 CRC error on reading the sector from the disk No code appears in the ERREG 0220 R W electronics failed maintenance mode test 0230 Word count overflow 0240 Density Error 0250 Wrong key word for set media density command 4 3 5 RX2II RXV21IProgramming Examples 4 3 5 1 Write Fill Buffer Figure 4 31 illustrates a program to write data on a disk by performing write and fill buffer sub routines Initially the write subroutine tests to see if there is an erro
50. 30 PO RO MO MO Fe qon eh G4 PI amp GH PO gt CA C4 3 PO 9 GOW a 4 Wb e Re Ri aD DD C4 C4 VIS CAR f O gt UU UT 2 OSAR b we n 898026 998806 908014 008822 8900538 000034 808836 800844 809958 000852 0820060 008866 608878 820874 089876 888128 298106 0208112 808116 830126 0800124 288126 298138 909134 228136 299148 8881 46 988152 080154 177178 177172 177172 177172 177172 212767 177772 212767 177778 012767 177772 216767 0898386 183767 177124 021773 116767 210074 108767 1771209 001775 116787 20262 032767 29848 2081774 0087587 177874 881081 2009899 032767 2408923 201414 232767 220092 081424 225267 00232 2021336 288228 225267 808174 201332 489800 8120787 24809824 203257 428160 881323 0008822 Figure 4 22 890520 889314 888519 177146 177126 177112 177182 177064 177934 177822 ABS PROGRAMMING EXAMPLES FOR THE RX11 Rx81 FLEXIBLE DISKETTE 1 ITHE FOLLOWING IS THE 11 STANDARD DEVICE ADORESS AND VECTOR ADORESS 5177178 COMMANG STATUS REGISTER 08 8177172 DATA BUFFER REGISTER 8 548177172 SECTOR ADORESS REGISTER RXTAs177172 TRACK ADORESS REGISTER RXESs177172 ERROR STATUS REGISTER FOLLOWING 18
51. 5 274 275 276 277 278 279 280 281 282 285 284 285 6312 0313 0314 2315 0316 8517 0320 2321 2322 8323 0324 8325 8326 8327 9332 8331 8332 0533 8334 8333 8377 9400 1284 3255 1377 30210 1260 1261 6701 6703 7418 8353 6795 8274 6784 7482 2255 5314 7402 6782 3418 8521 2377 2490 9098 2690 THE FOLLOWING 15 A PROGRAMMING EXAMPLE OF PROTOCOL REQUIRED TO EMPTY THE SECTOR BUFFER OF 64 12 817 WORDS 12 BIT 00 OR EMPTY THE SECTOR BUFFER 128 8 B T BYTES 8 MODE EENTRY TAD 10 8 TRYS TO EMPTY THE SECTOR SUFFER DCA PTRY PARITY ERROR RETRY COUNTER ESETUP TAD BUFFER 1 PROGRAMS DATA BUFFER 10 AUTO INDEX REGISTER 10 TAO MODE 9 129817 108 IF 8 BIT TAD COMMAND 7 2 MEANS EMPTY BUFFER LCD 10 TO ISSUE THE COMMAND FOR A TRANSFER REQUEST FLAG BEFORE TRANSFERRING DATA THE PROGRAMS QATA BUFFER FROM THE RX31 SECTOR BUFFER WA T FOR A DONE FLAG TO THE COMPLETION OF THE EMPTY BUFFER COMMAND PRIOR TO TESTING THE ERROR FLAG ELOQP STR TEST FOR TR FLAG SKP TR NOY BET TEST FOR DONE FLAG JMP EMPTY TR FLAG SET SDN TEST FOR DONE FLAG Jat ELUUOF NOT TR OR BONE YET THE DONE PLAG 15 SET TEST FOR ANY ERRORS ONLY ERROR POSSIBLE 15 A PARITY ERROR SER TEST THE ERROR FLAG HL NO ERRORS OK INCREMENT AND TEST THE PARITY ERROR RETRY PROGRAM LOCATI
52. 7 W 1 3 24 Vdc 31 W PDP 11 interface M7846 1 8 at 5 Vdc M8256 PDP 8 interface M8357 1 5 A at 5 Vdc LSI 11 interface 7946 1 8 A at 5 Vdc M8029 AC power 4 A at 115 Vac 2 A at 230 Vac 1 5 SYSTEMS COMPATIBILITY This section describes the physical electrical and logical aspects of compatibility for data interchange with IBM system 3740 devices and for data interchange with double density devices 1 5 1 Media The media used on the RX02 Floppy Disk system is compatible with the IBM 3740 family of equip ment and is shown in Figure 1 6 The diskette media was designed by applying tape technology to disk architecture resulting in a flexible oxide on mylar surface The diskette is encased in a plastic envelope with a hole for the read write head a hole for the drive spindle hub and a hole for the hard index mark The envelope is lined with a fiber material that cleans the diskette surface The media is supplied to the customer preformatted and pretested INDEX HOLE REGISTRATION HOLE READ WRITE HEAD APERTURE MA 1750 Figure 1 6 Diskette Media 1 9 1 5 2 Recording Scheme There two recording schemes used the RX02 double frequency FM and modified Miller code MFM The FM scheme is used for single density data recording which is compatible with IBM system 3740 devices When this recording scheme is used and the 02 is configured as shown in Figure 1 1 part the 2 is compati
53. 8 bit byte Done is asserted to end the function 4 1 2 3 Transfer Data Register XDR 67x2 With the maintenance flip flop cleared this instruc tion operates as follows A word is transferred between the AC and the interface register The direction of transfer is governed by the RX02 and the length of the word transferred is governed by the mode selected 8 bit or 12 bit When Done is negated executing this instruction indicates to the RX02 that The last data word supplied by the RX02 has been accepted by the PDP 8 and the RX02 can proceed or No The data or address word requested by the RX02 has been provided the PDP 8 and the 02 can proceed A data transfer from the AC always leaves the AC unchanged If operation 15 in 8 bit mode AC 0 3 are transferred to the interface register but are ignored by the 02 Transfers into the AC are 12 bit jam transfers when in 12 bit mode When in 8 bit mode the 8 bit word is ORed into AC 4 11 and 0 3 remain unchanged When the 2 is done this instruction can be used to transfer the RXES status word from the interface register to the AC The selected mode controls this transfer as indicated above 4 1 2 4 STR 67x3 This instruction causes the next instruction to be skipped if the transfer request TR has been set by RX02 and clears the flag The TR flag should be tested prior to transierring data or address words with the XDR instruction to ensure th
54. 80224 00525857 0299876 15 INC PTRY 699238 681555 5 RETRY 70 FILL THE SECTOR BUFFER 208232 208826 WALT PARITY ERROR THE TRANSFER REQUEST FLAG IS SET TRANSFER DATA FROM THE PROGRAMS BUFFER To THE RX81 SECTOR BUFFER 008034 3113087 176732 m MOVB 8 R8 PROGRAMS DATA BUFFER S 64 WORDS IN LENGTH 208040 000756 BR LOOP Figure 4 24 RXII RXVII Fill Buffer Example If an error occurs and the program executes a read error code function 111 a parity error may occur for that command The error status would not be for the error in which the read error code function was originally required The DRV SEL RDY bit is only updated at the time of a read status function 101 for both drives and after an Initialize depending on the status of drive 0 At the termination of any other functions it reflects the drive status of the last Read Status or Initialize command It is not required to load the Drive Select bit into the RXCS when the command is Fill Buffer 000 or Empty Buffer 010 Sector Addressing 1 26 No sector 0 Track Addressing 0 76 power failure causing the recalibration of the drives will result in a Done condition the same as finishing reading a sector However during a power failure RXES bit 2 Initialize Done will set Checking this bit will indicate a power fail condition Excessive use of the read status function 101 will result in drastically decreased through put because a read stat
55. 8E RX28 Figure 4 7 RX2SA Format RX8E RX28 00 01 02 03 04 05 6 07 08 09 10 11 12 BIT 8 OR 12 BIT NOT USED NOT USED MODE ONLY MODE MA 1860 1861 Figure 4 8 RX2DB Format RX8E RX28 Figure 4 9 RXES Format RX8E 4 6 Bit No Description 11 CRC Error cyclic redundancy check at the end of the data field has indicated an error The data must be considered invalid it is suggested that the data transfer be retried up to 10 times as most data errors are recoverable soft 9 Initialize Done This bit indicates completion of the Initialize routine It can be asserted due to 02 power failure system power failure or programmable or bus Initialize This bit 15 not available within the RXES from a read status function 5 Deleted Data DD In the course of reading data a deleted data mark was detected in the identification field The data following will be collected and transferred normally as the deleted data mark has no further significance within the 02 Any alteration of files or actual deletion of data due to this mark must be accomplished by user software This bit will be set if a successful or unsuccesful Write Deleted Data function is performed 4 Drive Ready This bit is asserted if the unit currently selected exists is properly supplied with power has a diskette installed properly has its door closed and has a diskette up to speed NOTE 1 This bit is only valid for either drive when retrieved via
56. A PROGRAMMING EXAMPLE OF THE PROTOCOL REQUIRED 170 WRITE WRITE DELETED DATA READ AT SECTOR THE CONTENTS OF PROGRAM LOCATION SECTOR OF TRACK T THE CONTENTS OF PROGRAM LOCATION TRACK START Mov 8 18 PTRY RETRY COUNTER MOV 8 18 CTAY CRE RETRY COUNTER MOV 8 18 STRY BEEK RETRY COUNTER WRITE DELETED DATA OA READ 1 BITS 4 THRU 1 PROGRAM LOCATION GQNTAIN THE FUNCTION j BIT 4 1 MEANS UNIT 1 B MEANS UNIT 8 8178 J THRU 1 19 TKE COMMAND 4 WRITE 44 WAITE OELETED DATA 6 READ wa RETRY COMMAND RXCS UNIT WRITE WAITE DELETED DATA OR READ WAIT FOR THE TRANSFER REQUEST FLAG THEN TRANSFER THE SECTOR ADDRESS 1 578 RXCS THE TRANSFER REQUEST FLAG BEQ 1 BEG UNTIL THE TRANSFER REQUEST FLAG SETS SECTOR AXSA LOAD SECTOR ADORESS 1 FoR THE TRANSFER FLAG THEN TRANSFER THE TRACK ADDRESS i 28 7578 RXxCS TEST THE TRANSFER REQUEST FLAG SEG 2 BEG UNTIL THE TRANSFER REQUEST FLAG BETS MOVB TRACK RXTA vOAD TRACK ADORESS j I THE SECTOR AND TRACK ADDRESSES HAVE BEEN TRANSFERRED THE i iHSAIlT FoR THE DoNE FLAG AND CHECK ANY ERRORS j IIF THE FUNCTION HAS COMPLETED SUCCESSFULLY No ERROR FLAG THEN HALT 351 817 0gNEBIT RXCS TEST Fgh THE DONE FLAG 8 0 3 BEQ UNTIL THE DONE FLAG SETS TST RXCS TEST FOR THE ERROR FLA
57. ADY 1 sel TR NOT SET LOOP UNTIL IT NOES 135 SECOND COMMAND wNARD CLA CLEAR THE AC AND JHP EL 90 GET OVER TO NEXT PAGE PAGE FOR TRANSFER REQUEST FLAG SEFORE TRANSFERRING TO THE PROGRAMS BUFFER FROM THE 8 01 SECTOR BUFFER FOR DONE FLAG TO INDICATE THE COMPLETION OF THE EMPTY BUFFER COMMAND PRIOS TO THE 99 FLAG EL30 STR TEST FOR TR FLAG EPE TR NOT SET TEST FLAG JMP EMPTY FLAG SET 80 TEST FOR DONE FLAG J E LOO OR DINE YET SINE FLAG 15 SET pias FOR ANY ERRORS TEST FOR THE ERROR HLT JNO ERRORS 2 TEST THE EROF 3ETRY PROGRAM LOCATION ETRY JAND QETRY TRE CO44AND UNTIL THE ERROR RECOVERS 753 INTIL THE COUNTER OVE3FLO4S TU 137 ETRY JMP RETRY YO EMPTY THE SECTOR BUFFER MLT ERROR 4 YUANSFER REQUEST FLAG IS SET YRANSFER DATA 12 THE PROGRAMS DATA RUFFER FROM THE Rx21 SECTOR BUFFER EMPTY XDA FROM THE 8 21 SECTOR BUFFER 1 118 THE PROGRAMS DATA BUFFER JMP FL OOF 4 908 UNTIL THE DONE FLAG SETS PAGE FILLOWING PROGRAM LOCATIONS ARE RESERVED FOR THE PROGRAMAJ DATA BUFFER BUFFER SaB 8 1874 Figure 4 16 RX28 Empty Buffer Example 4 21 4 1 8 Restrictions and Programming Pitfalls set of 11 restrictions and programming pitfalls
58. EK RX02 U G 001 digital equipment corporation e maynard massachusetts Ist Edition July 1978 Copyright 1978 by Digital Equipment Corporation The material in this manual is for informational purposes and is subject to change without notice Digital Equipment Corporation assumes no responsibility for any errors which may appear in this manual Printed in U S A This document was set on DIGITAL s DECset 8000 computerized typesetting system The following are trademarks of Digital Equipment Corporation Maynard Massachusetts DIGITAL DECsystem 10 MASSBUS DEC DECSYSTEM 20 OMNIBUS PDP DIBOL OS 8 DECUS EDUSYSTEM RSTS UNIBUS VAX RSX VMS IAS 11 82 15 CHAPTER 1 WWNNNNNN Ab Pene UJ 9 Go UJ p CHAPTER 2 CONTENTS Page GENERAL INFORMATION INFRODUC THON 1 1 1 2 nterlace Modules aas ambas ___ 1 2 oBtroller oeil 1 5 Read Write Elec psp Mis buta 1 5 El ctromecnanical DEVE iio eda MBA Reg ies 1 5 POWER SUD DIY R uin cus ope aei ios 1 6 OPTION DESCRIPTION e eiie siint 1 6 Operation For Single Density
59. EVICE ERROR HIT 115 SET THEN JERROR HALT J RETURN CD se Sm 1851 RX211 RXV21 Write Fill Buffer Example 4 44 4 3 5 2 Read Empty Buffer Figure 4 32 illustrates a program to read data from the disk by performing read and empty buffer subroutines The drive to be read is selected the read command and interrupt enable are set the density is set and the command 15 loaded the RX02 RXCS There is a wait for TR and then the sector address is loaded in the RX02 RXDB there is another wait for TR and the track address 15 loaded in the RX02 RXDB While the 02 controller reads data from the selected location on the selected disk into the 02 sector buffer the program waits for an interrupt to occur and then there 15 a jump to the empty buffer subroutine The empty buffer command is set the density is set and the command is loaded into the RX02 RXCS After a TR is received the word count is loaded into the RX02 RXDB there is another wait for TR and the address in memory where the data is to be stored is loaded into the RX02 RXDB The data is emptied from the sector buffer by the R X02 controller and when the buffer is emptied there is a return to the main program 58715 MODULE 2 7 PERD SUBROUTINE 89 53 G9 C CM
60. F OFF OFF ON OFF 2709 Figure 2 6 8 Modification 2 6 TESTING To test the operation of RX02 run the DEC diagnostics supplied Perform the diagnostics in the sequence listed for the number of passes time indicated RX8 or RX11 Diagnostic 2 passes Data Reliability Exerciser 3 passes DECX 8 DECX 11 10 minutes If any errors occur contact Field Service 2 10 CHAPTER 3 USER INFORMATION 3 1 CUSTOMER RESPONSIBILITY It is the user s responsibility to ensure that the 2 is located and operated in an area that is free from excessive dust and dirt and meets or exceeds the environmental conditions listed in Paragraph 1 4 The exterior of the 02 should be kept clean Also it is the user s responsibility to ensure that the diskettes are handled and stored properly in order to prevent errors or data loss which might occur when recording or reading data diskette handling procedures are described in Paragraph 3 2 32 CARE OF MEDIA 3 2 1 Handling Practices and Precautions To prolong the diskette life and prevent errors when recording or reading reasonable care should be taken when handling the media The following handling recommendations should be followed to prevent unnecessary loss of data or interruptions of system operation Do not write on the envelope containing the diskette Write any information on a label prior to affixing it to the diskette 2 Paper clips should not be used on the disk
61. G BNE ERFLAG BNE AN ERROR HAS OCCURED HALT COMPLETED i THE ERROR FLAG 19 SET ITHE CONTENTS oF THE RAKES ERROR STATUS 1F THE RXES BITS 1 AND s THEN SOME TYPE SEEK ERROR OCCURED THE AXES BIT 9 s 1 THEN A ERROR OCCUREO IF THE RXES 817 4 4 THEN TY ERROR HAS OCCURED CRFLAG 817 43 RXES TEST FOR CAC AND PARITY ERRORS BEQ SEEK NOY A PARITY OR 8057 SEEK BIT 82 RXES FOR PARITY ARQA BES CAC NOY A PARITY ERROR MUST A PARITY ERROR MAS OCCURED I INCREMENT TEST THE PARITY ERROR RETRY COUNTER PROGRAM LOCATION BTRY RETRY THE UNTIL THE PARITY ERROR RECOVERS 10 UNTIL THE COUNTER OVERFLOWS To 8 INC PTRY BNE RETRY RETRY THE COMMAND WALT HARD PARITY ERROR iA CRC ERROR HAS QCCUREO INCREMENT AND TEST THE ERROR RETRY COUNTER PROGRAM LOCATION CTRY j AND RETRY THE COMMAND UNTIL THE ERROR RECOVERS UNTIL TRE CTRY COUNTER QVERFLOHWS 8 CRCI INC CTRY BNE RETRY RETRY THE COMMAND HARD CAC ERROR THE ERROR FLAG 19 SET THE ERROR 15 NoT A PARITY ERRSR AND 18 CNQT ERROR THEREFORE MUST BE A SEEK ERROR STATE RXCS BITS 6 ANO i ARE 8 SEEK Mov SINIT RXCS POINITIALIAE INCREMENT AND TEST THE SEEK ERROR RETRY COUNTER PROGRAM LOCATION STRY i AND RETRY THE CoMMAND UNTIL THE SEEK ERROR RECOVERS JOR U
62. GRAM LOCATIONS ARE REFERENCED WITHIN THIS EXAMPLE 18 219 THE FOLLOWING 3 PROGRAM LOCATIONS ARE THE ERROR RETRY COUNTERS PTRY g ERROR RETRY COUNTER CTRY g CRC ERROR RETRY COUNTER STRY 8 SEEK ERROR RETRY COUNTER PROGRAM LOCATION MODE CONTAINS IF 12 817 ODE CONTAINS 108 IF 8 8IT MODE MODE 2 7 9 OR 168 PROGRAM LOCATION COMMAND CONTAINS THE TO BE ISSUED VIA THE 107 WRITE 4 WRITE DELETED DATA 44 QR READ 6 OR EMPTY BUFFER 2 COMMAND 8 4 14 OR 6 OR 2 PROGRAM LOCAT ON UNIT CONTAINS THE UN T DESIGNATION 0 0 OR UNIT 4 20 Uu g 7 0 OR 29 PROGRAM LOCATION SECTOR CONTAINS THE SECTOR ADDRESS 1 32 SECTOR 2 1 TO 59 OCTAL PROGRAM LOCATION TRACK CONTAINS THE TRACK ADDRESS 8 TO 414 TRACK 2 144 OCTAL PROGRAM LOCATION ASTATUS CONTAINS THE CONTENTS THE TRANSFER REGISTER THE DETECTION OF AN ERROR ERROR FLAG 1 WHICH CORRESPONDS THE CRROR STATUS 2 IF SEEK ERROR 1 IF CRC ERROR 2 IF PARITY ERROR ASTATUS 5 5 AT ERROR RX8E Write Write Deleted Data Read Example Sheet 2 of 2 4 15 228 229 230 231 232 235 234 255 256 237 258 259 240 241 242 243 244 245 246 247 248 249 258 251 252 255 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 27
63. I FLAG JEGUALS ZERU THEN IFILL RX402 BUFFER JSELECT DRIVE ISET TO SECTOR INT ENABLE JSET DENSITY JLOAD CUMMAND JGO AWAIT TRANSFER READY JiF FINI FLAG JEWUALS ZERO THEN JLORD ADDRESS IGO AWAIT TRANSFER READY JiF PINI FLAG JEQUALS ZERU THEN PLOAD RACK AUDRESS WALT FOR INTERRUPT RETUR em 09 40 60 M Ge OD E 49 Ge RED 6 MOLULF 4 1 FILL RX 2 BUFFER Se Se cs en pm Ob XR FD 98 FR RR CO SHAS D 9 Cp d m OUBUF MOV 815 KOV 151 MOV JSK IST JSR TST BNE TST BPL HALT ENDOL21 KTS 1 DERSTY CMD CHL RACS PC ATR Fir ENDOUA wOCKT FIN ENDOUA2 FIN ERDOU2 BRXCS ECOU 5 FILL BUFFER COMMAND ISET DENSITY JLOAD COMMAND P ALT FOR TR IF FINI FLAG JEQUALS ZFRO THEN JLOAD COUNT FOR TH FINI FLAG J QUALS ZEKO THEM JLOAU BASE ADR FOR OUTPUT BUPFER FOR DONE FINI FLAG pEGUALS ZERO THEN pIF D
64. IVALENTS DONEBITa4Q 1117 40008 BUFFERS 209 END Figure 4 23 Empty Buffer Example 4 32 211 112 115 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 155 154 135 136 137 138 139 148 141 142 145 144 145 146 147 148 149 150 151 152 155 154 155 156 157 158 THE FOLLOWING IS A PROGRAMMING EXAMPLE OF THE PROTOCOL REQUIRED TO IFILL THE BECTOR BUFFER WITH 128 89817 BYTES ALR CREE HO He a EN TCR al 008156 112767 177770 698142 FENTRY 918 PTRY B TRYS TO FILL THE SECTOR BUFFER 008164 012700 000342 SETUP MOV BUFFER PROGRAMS DATA BUPFER 0001702 216767 3020140 176772 MOV COMMAND RXCS ISSUE THE COMMAND T FOR A TRANSFER REQUEST FLAG BEFORE TRANSFERRING DATA FROM THE PROGRAMS er BUFFER TO THE RXO1 SECTOR SUFFER FOR A DONE FLAT 72 INDICATE THE COMPLETION OF THE FILL BUFFER COMMAND PRIOR Yo TESTING THE ERROR FLAG MD 008204 032767 2020040 176756 BIT DONEBIT RXCS TEST FOR THE DONE FLAG 000212 001771 LOOP BEG UNTIL THE DONE FLAG SETS THE DONE FLAG 15 SET FoR ANY ERRORS ONLY ERROR POSSIBLE 15 PARITY ERROR 900214 205767 176750 TST RXCS 000220 001001 1 009222 208800 MALT NO ERRORS OK gt COMPLETE INCREMENT AND TEST THE PARITY ERROR RETRY PROGRAM LOCATION PTRY AND RETRY THE COMMAND UNTIL THE ERROR RECOVERS jg UNTIL THE PTRY COUNTER OVERFLOWS To 8 0
65. NTIL THE CTRY COUNTER OVERFLOWS 8 i INC STRY BNE RETRY RETRY THE BOMMAND MALT HARD SEEK ERROR RXII RXVII1 Write Write Deleted Data Read Example 4 31 160 161 162 165 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 168 161 182 185 184 185 186 187 188 189 190 191 192 195 194 195 196 197 198 199 228 221 222 205 204 286 227 228 229 218 211 252 214 214 216 216 217 218 219 220 221 222 223 224 225 226 227 228 229 238 231 232 008242 209259 000254 000262 208266 999279 208276 2080520 0005304 208526 208318 208314 420316 000320 200524 200326 200532 228332 020334 228336 900548 212787 212700 216767 109767 001014 232767 921771 0087687 901801 20000 405267 2015595 2020090 116732 029756 220808 920000 320058 290090 0280802 8006822 030942 240009 288342 200542 280021 177770 030342 080054 176722 0300240 176664 738912 176646 000056 176706 176672 i THE FOLLOWING IS A PROGRAMMING EXAMPLE OF PROTOCOL REQUIRED TO THE SECTOR BUFFER 128 8 gt 817 BYTES i 916 PTRY 8 TRYS EMPTY THE SECTOR BUFFER ESETUP MOV BUFFER PROHGRAMS DATA BUFFER MOV COMMAND RXCS ISSUE THE COMMAND iWAIT FoR A TRANSFER REQUEST FLAG BEFORE TRANSFERRING DATA To THE PROGRAMS iDATA BUFFER FRON THE SECTOR BUFFER WAIT FoR A DONE
66. ON 1 1 INTRODUCTION The 2 is a low cost random access mass memory device that stores data in fixed length blocks flexible diskettes with preformatted industry standard headers The R X02 interfaces with either a PDP 8 a PDP 11 or an LSI 11 system Various interface modules are selected according to the com puter being used and either single or double density recording The various configurations are Designation TL Computer Interface Recording Module Density RXSE PDP 8 M8357 Single RX28 PDP 8 M8357 Single or Double RXII PDP 11 M7846 Single RX211 PDP 11 M8256 Single or Double RXVI11 LSI 11 M7946 Single RXV21 LSI 11 M8029 Single or Double NOTE The single density recording configurations RXSE RX11 and RXV11 are compatible with the RX01 Floppy Disk System when the M7744 controller module has been switched to be compatible with these configurations See Table 2 2 The 02 consists of two flexible disk drives a single read write electronics module a micro programmed controller module and a power supply enclosed a rack mountable 10 1 2 inch self cooled chassis cable is included for connection to either PDP 8 interface module a PDP 11 interface module or an LSI 11 interface module The amount of data that can be stored on the RX02 varies according to the configuration The recording density can be different for each drive For each drive system using double density recording up to 512K 8
67. ON PTRY RETRY THE COMMAND UNTIL THE ERROR RECOVERS 08 UNTIL THE PTRY COUNTER OVERFLOWS TO E 158 PTRY JMP ESETUP RETRY TQ EMBTY THE SECTOR BUFFER HLT HARD PARITY ERROR THE TRANSFER REQUEST FLAG IS SET TRANSFER DATA TO THE PROGRAMS DATA BUFFER FROM THE RX861 SECTOR BUFFER EMPTY XDA FROM THE RXBL SECTOR BUFFER I TO THE PROGRAMS DATA BUFFER JMP ELOOP LOOP UNTIL THE DONE FLAG SETS PAGE THE FOLLOWING PROGRAM LOCATIONS ARE RESERVED FOR THE PROGRAMS DATA BUFFER BUFFER 0 eBUFFER 2g90 Figure 4 12 RX8E Empty Buffer Example 174 175 176 177 178 179 180 181 182 185 184 185 186 187 188 189 190 191 192 195 194 195 196 197 198 199 200 201 222 203 204 295 206 207 208 209 218 211 213 214 215 216 217 218 219 220 221 222 225 224 225 226 227 9266 9267 9278 9271 0272 8273 8274 8273 9276 0277 03500 0501 9302 2303 9304 8328 0506 0307 2318 8311 0018 1294 3255 1377 3010 1268 6791 6703 7418 5306 6705 8274 6704 7402 2255 3278 7402 1410 6782 7288 5274 THE FOLLOWING 1S A PROGRAMMING EXAMPLE OF PROTOCOL REQUIRED TO FlLL THE SECTOR BUFFER WITH 64 12 817 WORDS 12 BIT MODE OR FlLL THE SECTOR BUFFER WITH 128 8 BYTES 8 817 QOE 10 10 FENTRY TAD KM1g 8 TRYS TO FILL THE SECTOR BUFFER OCA PTRY ERROR RETRY COUNTER SETUP TAD BUFFER 1 PROGRAM
68. ONS THE STANDARD 107 DEVICE CODE 15 678 LC026701 10 TO LOAD THE COMMAND AC 13 THE COMMAND 67 107 TO LOAD OR READ THE TRANSFER REGISTER 51836703 10 7 TO SKIP QN A TRANSFER REQUEST FLAG 56267024 107 TO SKIP ON AN ERROR FLAG 61835725 1027 TO SKIP QN THE DONE FLAG 197926726 INTERRUPT ENABLE OFF 4 MEANS ON 131726787 7107 TO INITIZLIAE THE RX8 RXO1 SUBSYSTEM THE FOLLOWING 15 A PROGRAMMING EXAMPLE OF THE PROTOCOL REQUIRED TO WRITE WRITE DELETED DATA OR READ AT SECTOR S THE CONTENTS OF PROGRAM OCATION SECTOR OF TRACK T THE CONTENTS OF PROGRAM LOCATION TRACK 8 OR 12 817 MODE START KM18 912 OCA PTRY PARITY RETRY COUNTER TAD 10 CTRY CRC RETRY COUNTER TAD KML NCA STAY SEEK RETRY COUNTER WRITE WRITE DELETED DATA OR READ RETRY MODE 78 JF 121817 180 TAD COMMAND 4 WRITE 14 I WRITE DELETED QATA OR 6 IF READ UNIT 78 UNIT 28 YF UNIT 1 LCD 10T 67X4 TO LOAD THE COMMAND FOR THE TRANSFER REQUEST FLAG THEN TRANSFER THE SECTOR ADDRESS STR 101 67x3 To JMP 1 WA T FOR TRANSFER REQUEST FLAG SECTOR 7 170 32 0CTAL 107 YO LOAD SECTOR CLA CLA BECAUSE 107 XOR OOESN T FOR THE TRANSFER REQUEST FLAG THEN TRANSFER THE TRACK ADDRESS STR 10 67 3 TO JMP 41 FOR TRANSFER REQUEST TAD TRACK 8 114 0 6
69. RNAS JMP RETRY COMMAND 10 TIMES HLT THEN HALT CINSTANTS USED THIS CONF 218 ien 3828 RETRY COUNTERS CT3Y a ICIC ERROW COUNTER SEF RETRY COUNTER FETAY e FTLL AND EMPTY BJFFER COUNTER P30684 LOCATION C9NTAINS 2 12 217 MONE 02 Lee IF 89311 WIDE 2 LOCATION FUNCUN CONTAINS WRITE 14 IF WRITE DELETE 08 Jo TF FUNC IN JLICATIOCN ORTVEP HAS ALT ASSTGNMENTS va SINGLE OENSITY 27 INIT 1 SINGLE INIT 9 OENSTTY aeos 1 20986 OENSITY 4 LIT ATION IS AHERE THE 855 COMMAND 15 STORED Cowan LIC ATION SECTOR 45ST 1 T3 2 SECTII A LJCATION TRACK JST BF a 114 TRACK LICATION 4 TS USE STORE THE 5 OF STATIS REGISTER AN EQRQOR 9606035 THE STATUS 15 IN THE TRA SFFF WEGISTER wHEN 15 SET ASTAT JS 2 1872 Figure 4 14 28 Write Write Deleted Data Read Example Sheet 2 of 2 4 19 17 ive THE FOLLOWING 13 4 PROGRAMMING EXAMPLE FO PROTOCOL REQUIRED 173 178 FILL THE SECTOR BUFFER 175 2210 SELST 176 177 8322 1266 8 TRYS FILL THE SECTOR B
70. S DATA BUFFER 40 0 INDEX REGISTER 10 MODE O 12 817 108 IF B BIT 269 10T 79 ISSUE THE COMMAND WAIT FOR A TRANSFER REQUEST FLAG TRANSFERRING DATA FROM THE PROGRAMS BUFFER TO THE 01 SECTOR BUFFER WAIT FOR A DONE FLAG INDICATE THE COMPLETION THE FILL BUFFER COMMAND PRIOR TO TESTING THE ERROR FLAG LOOP STR TEST FOR TR FLAG SKP TR NOT SET TEST FOR DONE FLAG JMP FILL TR FLAG SET 50 TEST FOR DONE FLAG JMP LOOP NOT OR BONE YET THE DONE FLAG IS SET TEST ANY ERRORS ONLY ERROR POSSIBLE 1 A PARITY ERROR SER TEST FOR THE ERROR FLAG HL NO ERRORS OK INCREMENT AND TEST THE PARITY ERROR RETRY PROGRAM LOCATION PTRY RETRY THE COMMAND UNTIL THE ERROR RECOVERS QR UNTIL THE PTRY COUNTER OVERFLOWS TO 198 PTRY JM SETUP RETRY FILL THE SECTOR BUFFER ML T HARD PARITY ERROR THE TRANSFER REQUEST FLaG IS SET TRANSFER DATA FROM THE PROGRAMS DATA BUFFER TO THE RX81 SECTOR TAD A10 AUTO INDEX REGISTER 12 010 THE RX81 SECTOR BUFFER CLA CLA BECAUSE 107 XOR OOESN T JM LOOP LOOP UNTIL THE DONE FLAG SETS Figure 4 13 RXSE Fill Buffer Example 4 1 7 RX28 Programming Examples Figures 4 14 4 15 and 4 16 are programming examples for write write deleted data or read functions for fill buffer functions and for empty buffer func
71. T key or system power failure 4 2 4 Programming Examples 4 2 4 1 Read Data Write Data Figure 4 22 presents a program for implementing a write write deleted data or a read function depending on the function code that is used The first instructions set up the error retry counters PTRY CTRY and STRY The instruction RETRY moves the command word for a write write deleted data or read into the RXCS The set of three instructions beginning at the label 1 moves the sector address to the RXII RXVII after transfer request TR which is bit 7 has been set The three instructions beginning at the label 25 move the track address to the RX11 RXVII after TR has been set The group of instructions begin ning at the label 3 looks for the done flag to set and checks for errors An error condition indicated by bit 15 setting is checked beginning at ERFLAG If bit 01s set error has occurred and a branch is made to CRCER If a parity error has occurred a branch is made to PARER If neither of the above occurs a seek error is assumed to have occurred and a branch is made to SEEKER where the system is initialized In the case of a write function the sector buffer is refilled by a JMP to FILLBUF In the case of a read function a JMP is made to EMPBUFF In each of the PAR CRC and SEEK routines the command sequence is retried 10 times by decre menting the respective retry counter If an error persists after 10 tries it is a hard erro
72. U COMMAND 42RD FOR THAVSFEQ REQUEST FLAS THEN TRANSFER SECTOR 42DRESS WATT STR TU SKIP ON TRANSFER REQUEST 1 L30P UNTIL TR TAD SECTOR 1 32 CICTAL XDR 1 350 THE SECTOR CLA CLEAR wAT1T FOR TRANSFEQ REQUEST FLAS THEN TRANSFER TRACK 4928835 STe SKIP ON TRANSFER REQUEST jue L OP UNTIL TR Tan TRACK 72 To 114 OCTAL THE TRACK CLA CLEAR THF COMMAND PROTACIL MAS BEEN COMPLETED NOW FOR DONE ANS CHECK 259 EIRIAS 7 TO S IP ON DONE FLAG JMP LOOP UNTIL DUNE SER 137 YO SKIP ON ERROR FLAG 2 ERRORS SO WALT E3ROR FLAG 18 SET FAROW STATUS IS LOCATED IN THE TRANSFER REGISTER 1F STATUS s THEN CRO ERIN ICCURED STATUS s 22 T4EN DENSITY E3R2OR8 QCCURED STATUS 2 THEN SEEK E382Q OCCJURED XDR GET CONTENTS OF TRANSFER REGISTER STATUS AT DONE DCA ASTATUS AND SAVE IT ASK FOR CRC ERROR 817 AND AgTaTuS 1F NUT EQUAL TO ZED CRC SNA CLA ERROR OCCURED SO SKIP JENSIT A THEN CHECK FOR DENSITY ERRROR 152 CTRY COUNT RETRIES IF a 12 THEN SKIP JMP 17 RETRIES lt 17 THEN 53 IY AGAIN MLT MA 1871 Figure 4 14 RX28 Write Write Deleted Data Read Example Sheet 2 of 2 4 18 95 97 98 99 122 181 122 123 124 125 186 127 128 129 118 111 112 115 114 115 116
73. UFFER 178 8523 3272 Oca ETRY ERROM RETRY COUNTER 179 8324 1377 BETUS P30GRAMS DATA BUFFER 184 8335 5212 A10 INDEX REGISTER 160 181 23285 1275 TAD MODE IF 12BIT 180 AIT 182 9327 1275 Tap GET OENSITY 183 93123 S276 OCA C944AND STORE ASSEMBLED COMMAND 184 31 1276 TAD CAMAN GET COMMAND T3 185 8312 67231 LECO 1SSUE COMMAND RX 186 8313 127b GET SAVED COMMAND 187 31a 3267 ANN 5424 FOR BeBIY MODE 188 2315 7652 BNA CLA B BIT MNOE SET DO BeMODE PROTOCOL 168 316 5327 JMB OJP 1298 7 GO STRAIGHT FILL LOOP 19 3iy 1276 GET SAVED COMMAND 090 191 7125 CLL RTL GET d 5 8 8173 6 1 2 3 192 932 7386 RTL WORD THE 193 322 7224 RAL 7 LSB S BITS 8 9 12 11 OF 194 8394 5723 SYR 12 TO SKIP ON TRANSFER READY 195 2 2 5323 Jue as TR SET LOOP 17 NOES 196 8325 6722 18SuE SECOND COMMAND unRp 197 03525 171222 CLA CLEAR THE FILL LOOP 198 199 wATT TRANSFER REQUEST FLAG BEFORE TRANSFERRING FROM THE PROGRAMS 222 281 SUFFER TO THE 9 2 BUFFER 222 223 FOR MINE TO INDICATE THE COMPLETION OF THE FILL SUFFER COMMAND Payne TO 224 225 YESTING ERR2R FLAG 226 227 4397 b723 STR FOR TR FLAG 228 25 9 7812
74. X02 BA RX02 BC RX02 BD RX02 BA RX02 BC RX02 BD 2 X02 BD R 02 R X02 BC Model No R X02 BD RX02 BD 2 RX02 BC RX02 BD RX02 BA RX02 BC 51 230 V 50H Power Supply 115 60 Hz 115 V SO Hz 115 V 60 Hz 115 V 50 Hz 230 V 50 Hz 115 V 60 Hz 230 V 50 Hz 230 V 50 Hz 115 V 60 Hz 115 V 50 Hz 230 V 50 Hz 115 V 60 Hz 115 V 50 Hz 115 V 60 Hz 115 V 50 Hz 230 V 50 Hz ON Top View The 02 is capable of efficient operation in computer environments however the parameters of the operating environment must be determined by the most restrictive facets of the system which in this case are the diskettes 2 3 2 Temperature Relative Humidity The operating ambient temperature range of the diskette is 15 to 32 C 59 to 90 F with a max imum temperature gradient of 11 C hr 20 F hr The media nonoperating temperature range stor age is increased to 34 4 to 51 6 C 30 to 125 F but care must be taken to ensure that the media has stabilized within the operating temperature range before use This range will ensure that the media will not be operated above its absolute temperature limit of 51 6 C 125 F 2 4 Humidity control is important in any system because static electricity can cause errors any CPU with memory The 02 is designed to operate efficiently within a relative humidity range of 20 to 80 pe
75. XES is saved and tested to determine the error Paragraph 4 1 3 6 The RXES will not include the select drive ready bit If a parity error is detected the program increments and tests the PTRY retry counter If a parity error persists after 10 tries it is considered a hard error If 10 retries have not occurred a branch is made to RETRY and the sequence is repeated After a parity test the program tests to see if the CRC error bit is set If a CRC error is detected the program increments and tests the CTRY retry counter If a CRC error persists after 10 retries it is considered a hard error If 10 retries have not occurred a branch is made to RETRY and the sequence repeated seek error is assumed if neither a CRC nor a parity error is detected An Initialize INIT instruction is performed Paragraph 4 1 2 8 During a write or write deleted data function the sector buffer must be refilled because INIT will cause sector 1 of track of drive 0 to be read which will destroy the previous contents of the sector buffer The instruction sequence for a fill buffer function is not included in Figure 4 11 but is presented in Figure 4 13 After the system has been initialized the program increments and tests the STRY retry counter If a seek error persists after 10 tries it is considered a hard error If 10 retries have not occurred a branch is made to RETRY and the sequence repeated 4 1 6 2 Empty Buffer Function Figure 4 12 shows a program for
76. ated in the RX2DB upon completion of a function 15 14 13 12 11 10 09 08 07 06 05 04 03 02 01 00 WC CRC SEL ERR RESERVED RESERVED NOT USED NXM 1870 Figure 4 30 RX2ES Format RX211 RXV21 RXES bit assignments are Bit No 0 Description CRC Error A cyclic redundancy check error was detected as information was retrieved from a data field of the diskette The data collected must be considered invalid The RX2ES is moved to the RX2DB and Error and Done are asserted 1s suggested that the data transfer be retried up to 10 times as most errors are recoverable soft Initialize Done This bit 15 asserted the RX2ES to indicate completion of the Initialize routine which can be caused by RX02 power failure system power failure or programmable or bus Initialize RX AC LO This bit is set by the interface to indicate a power failure in the RX02 sub system Density Error This bit indicates that the density of the function in progress does not match the drive density Upon detection of this error the control terminates the operation and asserts Error and Done Drive Density This bit indicates the density of the diskette in the drive selected indicated by bit 8 The density of the drive is determined during read and write sector operations Deleted Data This bit indicates that in the course of recovering data the deleted data address mark was detected at the beginning of the data field
77. ble with the RX01 The MFM scheme is used for double density data recording which is compatible with DIGITAL double density devices but is not com patible with other manufacturers 1 5 2 1 Double Frequency FM For the double frequency recording scheme data is recorded be tween bits of a constant clock stream The clock stream consists of a continuous pattern of one flux reversal every four us Figure 1 7 data is indicated by an additional reversal between clocks i e doubling the bit stream frequency hence the name A data zero is indicated by no flux reversal between clocks A continuous stream of ones shown in the bottom waveform in Figure 1 7 would appear as a 2 bit stream and a continuous stream of zeros shown in the top waveform in Figure 1 7 would appear as a IF or fundamental frequency bit stream ALL ZEROS PATTERN CHANGING PATTERN ALL ONES PATTERN 4 1506 Figure 1 7 Flux Reversal Patterns for FM 1 5 2 2 Miller Code MFM or Miller code encodes clocks between data bits of a continuous data stream The data stream consists of flux reversals for a data and no flux reversal for a data Zero A clock is recorded only between data 2 Because it is possible to have double density data fields map into a preamble and ID mark the MFM encoding is modified slightly to prevent a false header from being detect
78. ces Section EK R X02 UG 001 Order No FIRST CLASS PERMIT NO 33 S BUSINESS REPLY MAIL Digital Equipment Corporation Technical Documentation Department Maynard Massachusetts 01754
79. ct These bits code one of the eight possible functions listed below scribed in Paragraph 4 2 3 These are write only bits Code Function 000 Fill Buffer 001 Empty Buffer 010 Write Sector 011 Read Sector 100 Not used 101 Read Status 110 Write Deleted Data Sector 111 Read Error Register 4 Unit select This bit selects one of the two possible disks for execution of the desired function This is a write only bit 5 Done This bit indicates the completion of a function Done will generate an interrupt when asserted if Interrupt Enable RX2CS bit 6 is set This is a read only bit 6 Interrupt Enable This bit is set by the program to enable an interrupt when the RX02 has completed an operation Done The condition of this bit is normally determined at the time a function is initiated This bit is cleared by Initialize and is a read write bit 7 Transfer Request This bit signifies that the RX11 or RXVI1 needs data or has data avail able This is a read only bit 8 13 Unused 14 RX Initialize This bit is set by the program to initialize the RX11 RXVII without initializing all devices on the Unibus This is a write only bit CAUTION Loading the lower byte of the RXCS will also load the upper byte of the RXCS 4 24 Upon setting this bit in the RXCS the RX11 RXVII will negate Done and move the head position mechanism of drive 1 if two are available to track 0 Upon completion of a successful Initia
80. ctor address The program again waits for TR and moves the desired track address to the RXDB and again TR is negated The 2 locates the desired track and sector verifies its location and writes the contents of the sector buffer onto the diskette When this is done an interrupt will occur if the program has enabled interrupts typical diskette read occurs in just the reverse way first locating and reading a sector into the buffer read sector and then unloading the buffer into core empty buffer In either case the content of the buffer is not valid if Power Fail or Initialize follows a fill buffer or read sector function 4 2 1 Register and Vector Addresses The RXCS register is normally assigned Unibus address 177170 and the RXDB register is assigned Unibus address 177172 The normal BR priority level is 5 but it can be changed by insertion of a different priority plug located on the interface module The vector address is 264 4 23 4 2 2 Register Description 4 2 2 1 RXCS Command and Status 177170 Loading this register while the RX02 is not busy with bit 071 will initiate a function as described below and indicated in Figure 4 17 Bits 0 4 are write only bits 15 14 13 12 1 10 09 08 07 06 05 03 02 O1 ERROR NOT USED TR GO RX INT UNIT INIT ENB SEL Figure 4 17 RXCS Format RX11 RXVII Bit No Description 0 Go Initiates a command to 02 This is a write only bit 1 3 Function Sele
81. de 4 1 3 2 Error Code Register Figure 4 5 Specific error codes can be accessed by use of the read error code function 111 Paragraph 4 1 4 9 The specific octal error codes are given in Paragraph 4 1 5 NOT USED ERROR CODE 1515 Figure 4 5 Error Code Register Format RX8E RX28A The maintenance bit M bit can be used to diagnose the RX8E interface under off line and on line conditions The off line condition exists when the BCOSL 15 cable is disconnected from the RX02 the on line condition exists when the cable is connected to the RX02 If an LCD I O transfer is issued with AC 4 1 the maintenance flip flop is set When the maintenance flip flop is set the assertion of RUN following XDR instructions is inhibited and all data register transfers are forced into the AC The maintenance bit allows the interface register to be written and read for maintenance checks The maintenance flip flop is cleared by Initialize or by a Load Command with AC 4 0 The following paragraphs describe more explicitly how to use the maintenance bit in an off line mode The contents of the interface buffer cannot be guaranteed immediately following the first Load Com mand which sets the maintenance flip flop However successive Load Command IOTs will guar antee the contents of the interface register The contents of the interface register can then be verified by using the XDR IOT to transfer those contents int
82. does not agree with the drive density Upon detection of this error the control terminates the operation and asserts error and done DRV DEN This bit indicates the density of the diskette in the drive selected 0 single 1 double Deleted Data DD In the course of reading data a deleted data mark was detected in the identification field The data following will be collected and transferred normally as the deleted data mark has no further significance within the RX02 Any alteration of files or actual deletion of data due to this mark must be accomplished by user software This bit will be set if a successful or unsuccessful write deleted data function is performed Drive Ready This bit is asserted if the unit currently selected exists is properly supplied with power has a diskette installed properly has its door closed and has a diskette up to speed NOTE 1 This bit is only valid for either drive when retrieved via a read status function or for drive 0 upon com pletion of an Initialize NOTE 2 If the error bit was set in the RX2CS but error bits are not set in the RX2ES specific error conditions can be accessed via a read error code function 4 1 4 Function Code Description The RX8E RX28 functions are initiated by means of the Load command described in Paragraphs 4 1 2 1 and 4 1 2 2 The done flag should be tested and cleared with the SDN instruction in order to verify that the RX8E RX28 is in the Done state prior to is
83. e jumper and circuit breaker JUMPER P1 SHIPPING POWER PLUGS RESTRAINT RED VOLTAGE VAC JUMPER CIRCUIT BREAKER 90 120 70 10696 02 3 5 12 12301 01 100 128 70 10696 01 3 5 12 123 1 01 184 240 70 10696 04 1 75 12 12301 00 200 256 70 10696 03 1 75 12 12301 00 1855 Figure 2 3 02 Rear View 2 1 44 Fire and Safety Precautions The RX02 Floppy Disk System presents no additional fire or safety hazards to an existing computer system Wiring should be carefully checked however to ensure that the capacity is adequate for the added load and for any contemplated expansion 2 2 CONFIGURATION GUIDELINES The most common 2 Floppy Disk System configurations available are listed in Table 2 1 Each interface module listed in the table plugs into a computer bus it is compatible with the applicable computer so that there is adequate power to operate each module The interconnections between each interface module and the 02 controller for each of the configurations in Table 2 1 is by a BCOSL 15 cable which is 4 6 m 15 ft maximum See Table 2 2 for the controller module configuration switch positions 2 3 2 3 1 Computer PDP 8 PDP 11 LSI 11 Designation General System Interface RX211 RXV21 RX8E RXVI1 RX28 Table 2 1 Interface Controller Module 2 3 ENVIRONMENTAL CONSIDERATIONS RX02 Configurations RX02 R
84. e RX2ES is moved to the interface register the error and done flags are set and the function is terminated 4 9 If the track address is legal the 02 moves the head of the selected drive to the selected track locates the requested sector transfers the contents of the sector buffer and a CRC character to that sector and sets Done Any errors encountered in the seek operation will cause the function to cease the RX2ES to be loaded into the interface register and the error and done flags to be set If no errors are encoun tered the RX2ES is loaded into the interface register and only the done flag is set NOTE The write sector function does not destroy the con tents of the sector buffer 4 1 4 4 Read Sector 011 This function moves a sector of data from a specified track and sector to the sector buffer Upon decoding this function the RX8E RX28 clears RX2ES and sets the TR flag signifying the request for the sector address The flag must be tested and cleared The sector address 15 then loaded into the interface register by means of the XDR command The TR flag is set signifying a request for the track address The flag is tested and cleared by the host processor and the track address is then loaded into the interface register by XDR command The legality of the track address is checked by the RX02 If illegal the error and done flags are set with the RX2ES moved to the interface register and the function is terminated Otherwi
85. e data or address has been received or transferred or after an LCD instruction to ensure the command is in the interface register In cases where an XDR follows an LCD the TR flag needs to be tested only once between the two instructions 4 3 4 1 2 5 SER 67 4 This instruction causes the next instruction to be skipped if the error flag has been set by an error condition in the 02 and clears the An error also causes the done flag to be set Paragraph 4 1 3 6 4 1 2 6 SDN 67x5 This instruction causes the next instruction to be skipped if the done has been set by the 02 indicating the completion of a function or detection of an error condition If the done flag is set it is cleared by the SDN instruction This flag will interrupt if interrupts are enabled 4 1 2 7 INTR 67x6 This instruction enables interrupts by the done flag if AC 11 1 It disables interrupts if AC 11 0 4 1 2 8 INIT 67x7 The instruction initializes the RX02 by moving the head position mechanism of drive if drive 1 is available to track 0 It reads track 1 sector of drive 0 It zeros the error and status register and sets Done upon successful completion of Initialize Up to 1 8 seconds may elapse before the RX02 returns to the Done state Initialize can be generated by the program or by the Omnibus Initialize 4 1 3 Register Description Only one physical register the interface register exists in the RX8E RX28 but it may repre
86. ector on the diskette and fill it with the contents of the internal buffer The initiation of the function clears RX2ES TR and Done 4 39 When is asserted the program must load the desired sector address into RX2DB which will drop TR When TR is again asserted the program must load the desired track address into the RX2DB which will drop TR TR will remain unasserted while the 02 attempts to locate the desired sector The diskette density is determined at this time and is compared to the function density If the densities do not agree the operation is terminated bit 4 RX2ES is set RX2ES is moved to the RX2DB Error bit 15 RX2CS is set Done is asserted and an interrupt is initiated if bit 6 RX2CS Interrupt Enable 15 set If the densities agree but the 02 15 unable to locate the desired sector within two diskette revolu tions the interface will abort the operation move the contents of RX2ES to the RX2DB set Error bit 15 RX2CS assert Done and initiate an interrupt if bit 6 RX2CS Interrupt Enable is set If the desired sector has been reached and the densities agree the RX211 RXV21 will write the 12810 or 6410 words stored in the internal buffer followed by a CRC character which is automatically calcu lated by the RX02 The 211 21 ends the function by asserting Done and if bit 6 RX2CS Interrupt Enable is set initiating an interrupt CAUTION The contents of the sector buffer are not valid data after
87. ed within a double density data field NOTE The modified MFM encoding is not compatible with other manufacturers The encoding algorithms for implementing modified MFM are Encoding Algorithm 1 MFM or Miller Code Algorithm Data Encoded Data Dn 1 Encoding Algorithm 42 MFM Modified Algorithm The decoding algorithm used in data separation is Encoded Dn 1 ooo0 Figure 1 8 shows the waveforms that are generated for a data stream of zeros and ones when FM code MFM code and modified MFM code are used DATA MODIFIED MFM H MODIFYING e ALGORITHM DATA d MODIFIED WHERE J DATA 2 DATA Figure 1 8 FM versus Encoding 1 11 1 8 3 Logical Format Data is recorded on only one side of the diskette This surface is divided into 77 concentric circles or tracks numbered 0 76 Each track is divided into 26 sectors numbered 1 26 Figure 1 9 Each sector contains two major fields the header field and the data field Figure 1 10 1 5 3 1 l POSTAMBLE 1 BYTE 0 h L E D TRANSDUCER OUTPUT PRE INDEX GAP 5320 BYTES SECTOR z4 SECTOR 2 SECTOR 3 SECTOR z SECTOR 26 SOFT INDEX MARK 1 BYTE ROTATION 1502 Figure 1 9 Track Format Each Track HEADER FIELD DATA FIELD DATA HEADER
88. er 177172 esee 4 36 RX2TA Track 4 37 RX2SA RX Sector AddIess 2 4 37 RX2WC RX Word Count Register 2212 2 4 37 RX2BA RX Bus Address 4 37 RX2DB RX Data 4 37 RX2ZES RX Errorand SUA 4 38 4 39 er 4 39 Empty Bullet OUT ta DU ese 4 39 W 4 39 Read Sector case sete _ 4 40 Set Media Density 100 usto pe Fut a bou uin eI 4 4 Maintenance Read Status 101 0 000022 4 4 Write Sector with Deleted Data 110 000000 4 41 Read Error Code LL D oes ven 4 4 RAO2 POWER N 4 42 PRT OE COVELY DU 4 43 RX211 RXV21 Programming Examples 22 224112 4 43 WY ELS 4 43 Wead Empty Bullet easter e 4 45 FIGURES Title Page 1 3 Front View of the Floppy Disk System 0 1 3 EUR 1
89. er of the module 6 Refer to Table 2 2 for the correct controller configuration switch positions 7 Refer to Table 2 3 for correct device code or addressing jumpers on the interface module 8 Insert the interface module into the Omnibus PDP 8 available SPC slot PDP 11 or LSI bus LSI 11 The PDP 11 and LSI 11 interface modules must be inserted in the lowest numbered available option location Modules that use DMA processing should have a higher priority than programmed I O devices For modules using DMA processing in the PDP 11 SPC slot ensure that the NPG NPG IN NPG OUT line CA1 CBI is cut on the backplane 9 Connect the RX02 ac power cord into a switched power source 10 Turn the power on watching for head movement the drive s during the power up initialize phase The head s should move one track toward the center and back to track zero 2 3 interface Code Jumper Configuration 670X 671X 672X 673X 674X 675X 676X 677X BR R Priority Unibus Address 17717X Installed SW10 OFF SWI BR7 54 08782 BR6 54 08780 BRS 54 08778 BRA 57 08776 A12 WI8 Removed 11 17 Removed A10 WI16 Removed A9 W15 Removed A8 W14 Installed A7 W13 Installed A6 W12 Removed 5 11 Removed SW9 OFF SW8 OFF SW7 OFF SW6 ON SW5 ON SW4 OFF SW3 OFF V3 W2 Removed V4 W3 Installed V5 WA V6 W5 Removed
90. ess of Selected Drive y For DMA interfaces the controller status soft register is sent to the interface at the end of the command The four status bits are included 8 bit word Unit Select bit 7 Density of Drive 1 bit 6 Head Load bit 5 Density of Drive 0 bit 4 Density of Read Error Register Command bit 0 The Track Address of the Selected Drive Error is only meaningful on a code 150 error The register contains the address of the cylinder that the head reached on a seek error When the RX02 senses the return of power it will remove Done and begin a sequence to Move each drive head position mechanism to track 0 Clear any active error bits Read sector of track 1 on drive 0 Assert nitialize Done in the RXES a ad dm Upon completion of the power up sequence Done is again asserted There is no guarantee that infor mation being written at the time of a power failure will be retrievable however all other information on the diskette will remain unaltered 4 3 3 9 RX02 Power Fail When the RX02 control senses loss of power within the 2 it will unload the head and abort all controller action The RXAC L line is asserted to indicate to the RX211 RXV21 that subsystem power is gone The RX211 RXV21 asserts Done and Error and sets the RXAC L bit in the RX2ES 4 42 4 3 4 Error Recovery There are two error indications given by the RX211 RXV21 system The maintenance read status function Paragraph 4
91. ette 3 Do not use writing instruments that leave flakes such as lead or grease pencils on the jacket of the media 4 Do not touch the disk surface exposed in the diskette slot or index hole 5 Do not clean the disk in any manner 6 Keep the diskette away from magnets or tools that may have become magnetized Any disk exposed to a magnetic field may lose information 7 Do not expose the diskette to a heat source or sunlight 8 Always return the diskette to the envelope supplied with it to protect the disk from dust and dirt Diskettes not being used should be stored in a file box if possible 9 When the diskette is in use protect the empty envelope from liquids dust and metallic materials 10 Do not place heavy items on the diskette 3 1 11 Do not store diskettes on top of computer cabinets places where dirt can be blown by fans into the diskette interior 12 Ifa diskette has been exposed to temperatures outside the operating range allow five min utes for thermal stabilization before use The diskette should be removed from its packaging during this time CAUTION Do not use paper clips on diskettes Do not expose the diskette to a heat source or sun light Keep the diskettes from magnetic fields Do not write on the diskette with an instrument that leaves an impression or flakes 3 2 2 Diskette Storage 3 2 2 1 Short Term Available for Immediate Use l Store diskettes in their enve
92. fer register These registers have been assigned bus addresses Paragraph 4 2 1 and can be read or loaded with certain exceptions using any instruction referring to their addresses The RX02 which includes the mechanical drive s read write electronics and controller con tains all the control circuitry required for implied seeks automatic head position verification and calculation and verification of the CRC it has a buffer large enough to hold one full sector of diskette data 128 8 bit bytes Information is serially passed between the interface and the 02 A typical diskette write sequence which is initiated by a user program would occur in two steps Fill Buffer command to fill the buffer is moved into the RXCS The Go bit Paragraph 4 2 2 1 must be set The program tests for transfer request TR When TR is detected the program moves the first of 128 bytes of data to the RXDB TR goes false while the byte is moved into the 2 The program retests TR and moves another byte of data when TR 15 true When the 02 sector buffer is full the Done bit will set and an interrupt will occur if the program has enabled interrupts 2 Write Sector A command to write the contents of the buffer onto the disk is issued to the RXCS Again the Go bit must be set The program tests TR and when TR is true the program moves the desired sector address to the RXDB TR goes false while the RX02 handles the se
93. fill buffer function the 02 will set the transfer request TR flag signaling a request for the first data word The TR flag must be tested and cleared by the host processor with the STR instructions prior to each successive XDR IOT Paragraph 4 1 2 4 The data word can then be transferred to the interface register by means of the The 2 next moves the data word from the interface register to the sector buffer and sets the TR flag as a request for the next data word The sequence above is repeated until the sector buffer has been loaded 64 data transfers for 12 bit mode or 128 data transfers for 8 bit mode After the 64th or 128th word has been loaded into the sector buffer the RX2ES is moved to the interface register and the R X02 sets the done flag to indicate the completion of the function Therefore it is unnecessary for the host processor to keep a count of the data transfers Any XDR commands after Done is set will result in the RX2ES status word being loaded in the AC The sector buffer must be completely loaded before the RX8E RX28 will set Done and recognize a new command An interrupt would now occur if Interrupt Enable were set 4 1 4 2 Empty Buffer 001 This function moves the contents of the sector buffer to the host proces sor Upon decoding this function RX2ES bits are cleared and the TR flag is set with the first data word in the interface register This TR flag signifies the request for a data transfer fr
94. flows and the control has zero filled the remain der of the sector buffer if necessary Done is asserted ending the operation If bit 6 RX2CS Interrupt Enable is set an interrupt is initiated Any read of the RX2DB during the data transfer is ignored by the interface After Done is true the RX2ES is located in the RX2DB register 4 3 3 2 Empty Buffer 001 This function is used to empty the contents of the internal buffer through the RX211 RXV21 for use by the host processor This data is in the buffer as the result of a previous Fill Buffer or Read Sector command The programming protocol for this function is identical to that for the Fill Buffer command The RX2CS is loaded with the command to initiate the function This function will ignore bit 4 RX2CS Unit Select RX2CS bit 8 Density must be selected to allow the proper word count limit When the command has been loaded the Done bit RX2CS bit 5 goes false When the TR bit is asserted the RX2WC may be loaded into the RX2DB When TR is again asserted the RX2BA may be loaded into the RX2DB The RX211 RXV21 assembles one word of data at a time and transfers it directly to memory Transfers occur until word count overflow at which time the operation is complete and Done goes true If bit 6 RX2CS Interrupt Enable is set an interrupt is initiated After Done is true the RX2ES is located in the data buffer register 4 3 3 3 Write Sector 010 This function is used to locate a desired s
95. function specified in AC 8 9 and 10 on the drive specified by AC 7 A new function cannot be initiated unless the RX02 has completed the previous function The command word is defined as shown Figure 4 1 The command word is described in greater detail in Paragraph 4 1 3 1 01 02 03 04 05 06 07 08 09 10 11 NOT USED MAINT NOT NOT USED USED MA 1853 Figure 4 1 LCD Word Format RXSE 4 2 4 1 2 2 RX28 Load Command First byte 67x1 second byte 67x2 This command transfers the contents of the AC to the interface register and clears the AC The RX02 begins to execute the function specified in AC 8 9 and 10 on the drive specified by AC 7 new function cannot be initiated unless the RX02 has completed the previous function The command word is defined as shown in Figure 4 2 and is described in greater detail in Paragraph 4 1 3 1 12 BIT MODE NOT RESERVED MAINT USED TRANSFER 6701 BYTE 1 8 BIT MODE _ 0 TRANSFER BYTE 2 6702 XDR 9 Figure 4 2 Command Word Format RX28 When operating in the 8 bit mode the Load command is stored in two 8 bit transfers The first 8 bits of the command word shown as bits 4 11 in Figure 4 2 are stored then TR is asserted and an XDR is performed to transfer the remaining bits of data bit 3 DEN and bit 2 as shown in Figure 4 2 right justified The extra bits in the second 8 bit transfer are filled with zeros Upon completing the transfer of the second
96. he hardware puts in the extra Os Data transfer requests occur 23 ms after the previous request was serviced for 12 bit mode 18 ms for 8 bit mode There is no maximum time between the transfer request from the R X02 and servicing of that request by the host processor This allows the data transfer to and from the R X02 to be interrupted without loss of data The RX28 interface allows two modes of data transfer 8 bit word length and 12 bit word length For each mode of data transfer there can be either single density or double density storage of data In the 12 mode single density recording 64 words are written in a diskette sector and the diskette capac ity is 128 128 12 bit words for double density there are 128 words written in a sector with a diskette capacity of 256 256 12 bit words In the 8 bit word mode single density recording 128 8 bit bytes are written in each sector and the diskette capacity is 256 256 8 bit bytes for double density there are 256 8 bit bytes written in a sector with a diskette capacity of 512 512 8 bit bytes For the 12 bit mode all 12 data words are loaded into the buffer and then the hardware forces zeros to add extra bits to the end of the buffer so that the buffer is filled 4 1 1 Device Codes The eight possible device codes that can be assigned to the interface are 70 77 These device codes define address locations of a specific device and allow up to eight 28 interfaces to be used on
97. his module converts the RX02 I O bus to the LSI 11 bus structure It controls interrupts to the CPU initiated by the RX02 decodes LSI 11 bus addresses for register selection and initiates NPR requests to transfer data between the RX02 and the host CPU main memory 1 4 SPECIFICATIONS System Reliability Minimum number of revo 3 million media head loaded lutions per track Seek error rate in 106 seeks Soft data error rate in 109 bits read or written Hard data error rate in 1012 bits read or written NOTE The above error rates only apply to DEC approved media that is properly cared for Seek error and soft data errors are usually attributable to random effects in the head media interface such as electrical noise dirt or dust Both are called soft errors if the er ror is recoverable in 10 additional tries or less errors cannot be recovered Seek error ret ries should be preceded by a recalibrate Drive Performance Capacity Recording 8 bit bytes 12 bit words Per diskette FM 256 256 128 128 MFM 512 512 256 256 Per track FM 3 328 1 664 MFM 6 656 3 328 Per sector FM 128 64 MFM 256 128 Data transfer rate Diskette to controller buffer 4 bit FM 2 us data bit MFM Buffer to CPU interface 1 2 us bit NOTE PDP 8 interface can operate in 8 or 12 bit modes under software control Track to track move Head settle time Rotational speed Recording surfaces per disk Tracks per disk
98. his bit is a 41 7 4 2 3 Function Codes Following the strict protocol of the individual function data storage and recovery on the RX11 and occur with careful manipulation of the RXCS and RXDB registers The penalty for violation of protocol can be permanent data loss summary of the function codes is presented below 000 Fill Buffer 001 Empty Buffer 010 Write Sector 011 Read Sector 100 Not used 101 Read Status 110 Write Deleted Data Sector 111 Read Error Register The following paragraphs describe in detail the programming protocol associated with each function encoded and written into RXCS bits 1 3 if Done is set 4 2 3 1 Buffer 000 This function is used to fill the RX02 buffer with 128 8 bit bytes of data from the host processor Fill buffer is a complete function in itself the function ends when the buffer has been filled The contents of the buffer can be written onto the diskette by means of a subsequent write sector function or the contents can be returned to the host processor by an empty buffer func tion RXCS bit 4 Unit Select does not affect this function since no diskette drive is involved When the command has been loaded RXES OUT and Done are cleared When the TR bit is asserted the first byte of the data may be loaded into the data buffer The control then clears TR and after supplying the appropriate number of shift pulses to store the data again asserts TR The same TR cycle will occur a
99. iguration plugs are provided to adapt the H771 C or D to each voltage range This is not applicable to the H771 A 1 3 OPTION DESCRIPTION The optional interface modules that are used to interface the 02 with a PDP 8 PDP 11 LSI 11 are listed Paragraphs 1 1 and 1 2 Each module is powered by the host processor The module selected is determined by the computer being used and whether the data interchange is between either IBM system 3740 compatible devices or DIGITAL system double density devices Also when an M7744 controller module s configuration switch is set to be compatible the RX02 can operate as an RXOI The RX02 interfaces with IBM compatible devices when single density data recording is used The 02 interfaces with DIGITAL system double density recording devices when the controller module configuration switch is positioned to be compatible with RX28 RX211 and RXV21 con figurations 1 3 1 Operation For Single Density Recording Only RX8E RX11 RXVI1 1 3 1 1 PDP 8 Operation The RX02 connects to the M8357 Omnibus interface module This mod ule converts the RX02 I O bus to PDP 8 family Omnibus structure It controls interrupts to the CPU initiated by the RX02 controls data interchange between the RX02 and the host CPU by programmed I O and handles input output transfers used for maintenance status conditions 1 3 1 2 PDP 11 Operation The RX02 connects to the M7846 Unibus interface module This module convert
100. inet as shown in Figure 1 4 The M7744 is hinged on the left side and lifts up for access to the M7745 read write electronics module 1 2 3 Read Write Electronics The M7745 read write electronics module is located in the 2 cabinet as shown in Figure 1 4 M7744 CONFIGURATION SWITCH BCOSL 15 INTERFACE CABLE A 2 49 3 4 READ WRITE ELECTRONICS MODULE 1751 Figure 1 4 View of RX02 1 2 4 Electromechanical Drive A maximum of two drives can be attached to the read write electronics The electromechanical drives are mounted side by side under the read write electronics board M7745 Figure 1 5 is an underside view of the drive showing the drive motor connected to the spindle by a belt This belt and the drive pulley are different on the 50 Hz and 60 Hz units see Paragraph 2 1 3 2 for complete input power modification requirements DRIVE MOTOR DRIVE SPINDLE BELT PULLEY AC DRIVE MOTOR AC POWER CONNECTOR DC STEPPER MOTOR 1850 Figure 1 5 Underside View of Drive 1 2 5 Power Supply The H771 power supply is mounted at the rear of the 02 cabinet as shown in Figure 1 4 The H771 A 1s rated at 60 Hz 1 2 Hz over a voltage range of 90 128 Vac The H771 C and D are rated at 50 Hz 1 2 Hz over four voltage ranges 90 120 Vac 3 5 A circuit breaker H771 C 100 128 Vac 184 240 Vac 1 75 A circuit breaker H771 D 200 256 Vac Two conf
101. isually inspect for any damage as indicated Paragraph 2 4 3 3 Separate Container Open the carton Figure 2 4 and remove the packing pieces Lift the RX02 out of the carton Remove the shipping fixtures from both sides of the RX02 and inspect for shipping damage as indicated in Paragraph 2 4 3 3 Attach the inside tracks of the chassis slides provided in the carton to the RX02 Figure 2 1 Locate the proper holes in the cabinet rails Figure 2 5 and attach the outside tracks to the cabinet Place the tracks attached to the R X02 inside the extended cabinet tracks and slide the unit in until the tracks lock in the extended position Attach the front bezel with the screws supplied Locate the RX02 cover in the cabinet above the unit and secure it to the cabinet rails Figure 2 5 2 6 SLIDES DISKETTES SCORED SHEET DUST COVER PLYWOOD HOLDING FIXTURE PLYWOOD HOLDING FIXTURE M m WASHER 8 SHIPPING BRACKET REGULAR SLOTTED CARTON SHIPPING CARTON MA 1854 Figure 2 4 RX02 Unpacking dhje SCREWS CHASSIS SLIDES 1594 Figure 2 5 02 Cabinet Mounting Information 2 7 2 4 3 3 Inspection 229 1 Inspect the front cover s of the RX02 to be sure it operates freely Compress the latch which allows the spring loaded front cover to open 2 Inspect the rear of the RX02 chassis to be sure there are no broken
102. lize the RX02 will zero the error and status register set Initialize Done and set RXES bit 7 RDY if unit 0 15 ready It will also read sector of track on drive 0 15 Error This bit is set by the RX02 to indicate that an error has occurred during an attempt to execute a command This read only bit is cleared by the initiation of a new command or an Initialize Paragraph 4 2 6 4 2 2 2 Data Buffer Register 177172 This register serves as a general purpose data path between the 02 and the interface It may represent one of four RXO2 registers according to the protocol of the function in progress Paragraph 4 2 3 This register is read write if the 02 is not in the process of executing a command that is it may be manipulated without affecting the RX02 subsystem If the 02 is actively executing a command this register will only accept data if RXCS bit 7 TR is set In addition valid data can only be read when TR is set CAUTION Violation of protocol in manipulation of this register may cause permanent data loss 4 2 2 5 RXTA RX Track Address Figure 4 18 This register is loaded to indicate on which of the 77 114g tracks a given function is to operate It can be addressed only under the protocol of the function in progress Paragraph 4 2 3 Bits 8 15 are unused and are ignored by the control 1510 Figure 4 18 RXTA Format RXII RXVI1 4 2 2 4 RXSA RX Sector Address Figure 4 19
103. ller sector buffer The initiation of this function clears RXES Done and OUT When TR is asserted the program must load the desired sector address into the RXDB which will negate TR When TR is again asserted the program must load the desired track address into the RXDB which will negate TR If the desired track is not found the RXI1 RXVI1 will abort the operation move the contents of the RXES to the RXDB set RXCS bit 15 Error assert Done and initiate an interrupt if RXCS bit 6 Interrupt Enable is set 4 28 Done will remain negated while the 2 attempts to locate the desired track and sector If the 02 is unable to locate the desired sector within two diskette revolutions after locating the presumably correct track the RX11 RXV11 will abort the operation move the contents of the RX ES to the RXDB set RXCS bit 15 Error assert Done and initiate an interrupt if RXCS bit 6 Interrupt Enable is set If the desired sector is successfully located the control will attempt to locate a standard data address mark or a deleted data address mark If either mark is properly located the control will read data from the sector into the sector buffer If the deleted data address mark was detected the control will assert RXES bit 6 DD As data enters the sector buffer a CRC is computed based on the data field and CRC bytes previously recorded A non zero residue indicates that a read error has occurred The cont
104. lopes 2 Store horizontally in piles of ten or less If vertical storage is necessary the diskettes should be supported so that they do not lean or sag but should not be subjected to compressive forces Permanent deformation may result from improper storage 3 Store in an environment similar to that of the operating system at a minimum store within the operating environment range 3 2 2 2 Long Term When diskettes do not need to be available for immediate use they should be stored in their original shipping containers within the nonoperating range of the media 3 2 3 Shipping Diskettes Data recorded on disks may be degraded by exposure to any sort of small magnet brought into close contact with the disk surface If diskettes are to be shipped in the cargo hold of an aircraft take precautions against possible exposure to magnetic sources Because physical separation from the mag netic source is the best protection against accidental erasure of a diskette diskettes should be packed at least 3 inches within the outer box This separation should be adequate to protect against any magnetic sources likely to be encountered during transportation making it generally unnecessary to ship dis kettes in specially shielded boxes When shipping be sure to label the package DO NOT EXPOSE TO PROLONGED HEAT OR SUNLIGHT When received the carton should be examined for damage Deformation of the carton should alert the receiver to possible damage
105. lotes Desde 2 10 TESTIN AMT ETE 2 10 USER INFORMATION CUSTOMER RESPONSIBIBIT Y nace a 3 1 CARP MEDIA 3 1 Handling Practicesand Precautions ere n 3 DUSK GUC StOFAPE c 3 2 Short Term Available for Immediate 5 4 3 2 Lone Teri een eon 3 2 DMP PINS DISK CUES icra ane bid D eM dd 3 2 OPEKATING INST RUG uoce db 3 3 OPERATOR TROUBLESHOOTING n 3 3 PROGRAMMING RX8E AND RX28 Programming Information 2 4 1 Dev Ce 4 1 Douce 4 2 RASELoadtCommiandtE GE atu 4 2 Load 4 3 Transter Data Register CX DIS 4 3 SE 4 3 BEI pru UM dM 4 4 SINN E E 4 4 PN B I eec 4 4 4 4 1 4 1 3 4 1 3 1 4 1 3 2 4 1 3 3 4 1 3 4 4 1 3 5 4 1 3 6 4 1 3 7 4 1 4 4 1 41 4 1 4 2 4
106. many tries for an IDAM identifies header 0170 Data AM not found in allotted time 0200 CRC error on reading the sector from the disk No code appears in the ERREG 0210 parity errors 0220 Self diagnostic error on Initialize 0240 Density Error 4 1 5 2 RX28 There are two error indications given by the RX28 system The read status function will assemble the current contents of the RX2ES which can be sampled to determine errors The read error register function can also be used to retrieve explicit error information The results of the read status function or the read error register function are in the interface register when Done sets indicating the completion of the function The XDR IOT must be issued to transfer the contents of the interface register to the PDP 8 s AC NOTE A read status function is not necessary if the DRV RDY bit is not going to be interrogated because the RX2ES is in the interface register at the completion of every function The error codes for the read error register function are presented below Octal Code Error Code Meaning 0010 Drive 0 failed to see home on Initialize 0020 Drive 1 failed to see home on Initialize 0040 Tried to access a track greater than 76 0050 Home was found before desired track was reached 0070 Desired sector could not be found after looking at 52 headers 2 revolutions 0110 More than 40 us and no SEP clock seen 0120 preamble could not be found 0130 Preamble fo
107. ne are asserted Initialize Done This bit is asserted in the RXES to indicate completion of the Initialize routine which can be caused by RX02 power failure system power failure or programmable or Unibus Initialize Density Error This bit is asserted to indicate the density of the function in progress does not match the drive density Upon detection of this error the control terminates the oper ation and Error and Done are asserted NOTE Bits 4 and 5 are asserted for the occurrence of double density when the system is RX01 compatible Drive Density This bit indicates the density of the diskette in the drive selected When asserted double density is indicated Deleted Data Detected During data recovery the identification mark preceding the data field was decoded as a deleted data mark Paragraph 1 5 3 2 4 26 7 Drive Ready This bit is asserted if the unit currently selected exists is properly supplied with power has a diskette installed correctly has its door closed and has a diskette up to speed NOTE 1 The drive ready bit is only valid when retrieved via a read status function or at completion of Initialize when it indicates status of drive 0 NOTE 2 If the error bit was set in the RXCS but error bits are not set in the RXES specific error conditions can be accessed via a read error register function Para graph 4 2 3 7 8 Unit Select Drive 0 is selected if this bit is 0 drive 1 is selected if t
108. o the AC 4 5 In addition the maintenance flip flop directly sets the skip flags which will remain set as long as the maintenance flip flop is set Skipping on these flags as long as the maintenance flip flop is set will not clear the flags Setting and then clearing the maintenance flip flop will leave the skip flags in a set condition The skip IOTs can then be issued to determine whether or not a large portion of the interface skip logic is working correctly With the maintenance flip flop set it can be determined if the interface is capable of generating an interrupt on the Omnibus When the maintenance flip flop is set the done flag is set and the interrupt enable flip flop can be set by issuing INTR with AC 11 1 The combination of done and interrupt enable should generate an interrupt The maintenance flip flop can also be used to test the INIT The maintenance flip flop is set and cleared to generate the flags and INIT is then executed If execution of INIT is internally successful all of the flags and the interrupt enable flip flop should be cleared if they were previously set In the on line mode use of the maintenance bit should be restricted to writing and reading the inter face register The same procedure described to write and read the interface register in the off line mode should be implemented in the on line mode Exiting from the on line maintenance bit mode should be finalized
109. om the RX8E RX28 to the host processor The flag must be tested and cleared then the word can be moved to the AC by an XDR command The direction of transfer for an XDR command is controlled by the RX02 The TR flag is set again with the next word in the interface register The above sequence is repeated until all words or bytes have been transferred thus emptying the sector buffer The done flag is then set after the RX2ES is moved in the interface register to indicate the end of the function An interrupt would now occur if Interrupt Enable were set NOTE The empty buffer function does not destroy the con tents of the sector buffer 4 1 4 3 Write Sector 010 This function transfers the contents of the sector buffer to a specific track and sector on the diskette Upon decoding this function the RX8E RX28 clears the RX2ES and sets the TR flag signifying a request for the sector address The TR flag must be tested and cleared before the binary sector address can be loaded into the interface register by means of the XDR command The sector address must be within the limits 1 32 The TR flag is set signifying a request for the track address The TR flag must be tested and cleared then the binary track address may be loaded into the interface register by means of the XDR com mand The track address must be within the limits 0 1 148 The 02 tests the supplied track address to determine if it is within the allowable limits If it is not th
110. r The retry counters can be set up to retry as many times as desired NOTE fill buffer function is performed before a write function and an empty buffer function is performed after a read function 4 2 4 Empty Buffer Function Figure 4 23 shows a program for implementing an empty buffer function The first instruction sets the number of error retries to 10 The address of the memory buffer is placed in register RO and the Empty Buffer command is placed in the RXCS Existence of a parity error is checked starting at instruction 35 If a parity error is detected the Empty Buffer command is loaded again If an error persists for 10 retries the error is considered hard If no error is indicated the program looks for the transfer request TR flag to set The error flag is retested if TR is not set Once TR sets a byte is moved from the RX11 RXVI11 sector buffer to the core locations of BUFFER The process continues until the sector buffer is empty and the Done bit is set 4 2 4 3 Fill Buffer Function Figure 4 24 presents a program to implement a fill buffer function It is very similar to the empty buffer example 4 2 5 Restrictions and Programming Pitfalls A set of restrictions and programming pitfalls for the RX11 RXVI11 is presented below l Depending on how much data handling is done by the program between sectors the min imum interleave of two sectors may be used but to be safe a three sector interleave is recom mended 4
111. r from the last operation If there 1s an error a branch is made and the write subroutine is not performed otherwise a jump is made to the fill buffer subroutine Before data can be written the RX02 sector buffer must be filled The Fill Buffer command is set the density single or double is set and the command is loaded in the RX02 RXCS After a TR is received the word count for either 128 256 bytes of data is loaded in the RX02 RXDB After another TR is received the starting address where data will be retrieved from memory is loaded the RX02 RXDB The RX02 controller fills the sector buffer with the number of bytes indicated then the RX02 controller sets the Done bit If an Error is detected the Error bit is set in the RXCS and the program halts The program returns to the write subroutine the drive is selected the write command and interrupt enable are set the density is set and the command is loaded in the RX02 RXCS There is a wait for TR then the sector address is loaded in the RX02 RXDB there 15 another wait for TR and the track address is loaded in the 2 The data loaded in the sector buffer is written by the RX02 controller on the selected drive disk at the selected track and sector While the controller writes the data the program waits for an interrupt which signifies the completion of write data to occur in order to return to the main program 4 43 981166 2061172 801174 841204 071262 901214
112. rcent with a maximum wet bulb temperature of 25 C 77 and a minimum dew point of 2 36 F 2 3 3 Heat Dissipation The heat dissipation factor for the RX02 Floppy Disk System is less than 225 Btu hr By adding this figure to the total heat dissipation for the other system components and then adjusting the result to compensate for such factors as the number of personnel the heat radiation from adjoining areas and sun exposure through windows the approximate cooling requirements for the system can be deter mined It is advisable to allow a safety margin of at least 25 percent above the maximum estimated requirements 2 3 4 Radiated Emissions Sources of radiation such as FM vehicle ignitions and radar transmitters located close to the com puter system may affect the performance of the RX02 Floppy Disk System because of the possible adverse effects magnetic fields can have on diskettes A magnetic field with an intensity of 50 oersteds or greater might destroy all or some of the information recorded on the diskette 2 3 5 Cleanliness Although cleanliness is important in all facets of a computer system it is particularly important in the case of moving magnetic media such as the 02 Diskettes are not sealed units and are vulnerable to dirt Such minute obstructions as dust specks or fingerprint smudges may cause data errors Therefore the RX02 should not be subjected to unusually contaminated atmospheres especially one with
113. rol sets RXES bit 0 CRC Error and RXCS 15 Error The ends the operation by moving the contents of the RXES to the RXDB sets Done and initiates an interrupt if RXCS bit 6 Interrupt Enable is set 4 2 3 5 Read Status 101 The RX11I RXVII will negate RXCS bit 5 Done and begin to assemble the current contents of the RXES into the RXDB RXES bit 7 Drive Ready will reflect the status of the drive selected by RXCS bit 4 Unit Select at the time the read status function was given All other RXES bits will reflect the conditions created by the last command RXES may be sampled when RXCS bit 5 Done is again asserted interrupt will occur if RXCS bit 6 Interrupt Enable is set RXES bits are defined in Paragraph 4 2 2 6 NOTE The average time for this function is 250 ms Exces sive use of this function will result in substantially reduced throughput 4 2 3 6 Write Sector with Deleted Data 110 This operation is identical to function 010 write sector with the exception that a deleted data address mark precedes the data field instead of a stand ard data address mark Paragraph 1 5 3 2 4 2 3 7 Read Error Code Function 111 The read error code function can be used to retrieve explicit error information provided by the controller upon detection of the general error bit The func tion is initiated and bits 0 6 of the RXES are cleared Out is asserted and Done is negated The controller then generate
114. s each byte of data is loaded The RX02 counts the bytes transferred it will not accept less than 128 bytes and will ignore those in excess Any read of the RXDB during the cycle of 128 transfers is ignored by the RX11 RXVI1 When the complete buffer has been filled the control asserts Done 4 2 3 2 Empty Buffer 001 This function is used to empty into the interface the buffer of the 128 data bytes loaded from a previous Read Sector or Fill Buffer command This function will ignore RXCS bit 4 Unit Select and negate Done For this function TR and shift pulses are generated in the same manner as for the fill buffer but the buffer is emptied 4 27 When TR sets the program may unload the first of 128 data bytes from the RXDB Then the RX11 RXV11 again negates TR When TR resets the second byte of data may be unloaded from RXDB which again negates TR Alternate checks on TR and data transfers from the RXDB continue until 128 bytes of data have been moved from the RXDB Done sets ending the operation NOTE The empty buffer function does not destroy the con tents of the sector buffer 4 2 3 3 Write Sector 010 This function is used to locate a desired track and sector and write the sector with the contents of the internal sector buffer The initiation of this function clears TR and Done When TR is asserted the program must move the desired sector address into the RXDB which will negate TR When TR is again asserted the program
115. s the RX02 I O bus to PDP 11 Unibus structure It controls interrupts to the CPU initiated by the RX02 decodes Unibus addresses for register selection and handles data interchange between the 02 and the host CPU main memory by programmed 1 1 3 1 3 LSI 11 Operation The 2 connects to the M7946 1 51 11 bus interface module This module converts the RX02 I O bus to the LSI 11 bus structure It controls interrupts to the CPU initiated by the RX02 decodes LSI 11 bus addresses for register selection and transfers data between the RX02 and the host CPU main memory by programmed 1 1 3 2 Operation For Single or Double Density Recording RX28 RX211 RXV21 1 3 2 1 PDP 8 Operation RX02 connects to the M8357 Omnibus interface module This mod ule converts the RX02 I O bus to PDP 8 family Omnibus structure It controls interrupts to the CPU initiated by the RX02 controls transfer of data between the RX02 and host CPU by programmed I O and handles input output transfer used to test status conditions 1 3 2 2 PDP 11 Operation The RX02 connects to the M8256 Unibus interface module This module converts the RX02 I O bus to PDP 11 Unibus structure It controls interrupts to the CPU initiated by the RX02 decodes Unibus addresses for register selection and initiates NPR requests to transfer data between the 02 and the host CPU main memory 1 3 2 3 LSI 11 Operation The RX02 connects to the M8029 LSI 11 bus interface module T
116. s the appropriate number of shift pulses to transfer the specific error code to the interface register and completes the function by asserting Done The interface register can now be read and the error code interrogated to determine the type of failure that occurred Paragraph 4 2 6 NOTE Care should be exercised in the use of this function since under certain conditions erroneous error infor mation may result Paragraph 4 2 5 4 2 3 8 Power Fail There is no actual function code associated with Power Fail When the RX02 senses a loss of power it will unload the head and abort all controller action All status signals are invalid while power is low When the 02 senses the return of power it will remove Done and begin a sequence to Move drive 1 head position mechanism to track O Clear any active error bits Read sector 1 of track 1 of drive 0 into the sector buffer Set RXES bit 2 Initialize Done Paragraph 4 2 2 6 after which Done is again asserted Set Drive Ready of the RXES according to the status of drive 0 FP 4 29 There is no guarantee that information being written at the time of a power failure will be retrievable However all other information on the diskette will remain unaltered A method of aborting a function is through the use of RXCS 14 RX Initialize Another method is through the use of the system Initialize signal that is generated by the PDP 11 RESET instruction the console STAR
117. se the 02 moves the head to the specified track locates the specified sector transfers the data to the sector buffer computes and checks CRC for the data If no errors occur the done flag is set with the RX2ES in the interface register If an error occurs anytime during the execution of the function the function is terminated by setting the error and done flags with RX2ES in the interface register A detection of CRC error results in RX2ES bit 11 being set Ifa deleted data mark was encountered at the beginning of the desired data field RX2ES bit 5 is set 4 1 4 5 Set Media Density 100 for RX28 only This function causes the entire diskette to be reas signed to a new density The density bit bit 3 RX2CS indicates the new density of the diskette The control reformats the diskette by writing new data address marks double or single density and zero ing out all data fields on the diskette Before executing the command the control will look for a protective key word of 01001001 8 The control starts at sector 1 track 0 and reads the header information then starts a write operation writing the new data address mark and data field as well as CRC characters If the header information is damaged the control will abort the operation and assert DONE and ERROR This operation takes about 15 seconds and should not be interrupted If for any reason the operation 15 interrupted an illegal diskette has been generated which may have da
118. sent one of the six RX02 registers described in the following paragraphs according to the protocol of the function in progress 4 1 3 1 Command Register Figures 4 3 and 4 4 The command is loaded into the interface register by the LCD instruction for RX8E and by a load command LCD and for the RX28 Para graphs 4 1 2 1 and 4 1 2 2 00 01 02 03 04 05 06 07 08 09 10 11 NOT USED MAINT NOT NOT USED USED 1793 Figure 4 3 Command Register Format RX8E 00 01 02 03 04 07 08 09 10 11 05 06 TN L UNIT NOT RESERVED MAINT NOT USED SEL NOT USED USED 1ST BYTE 8 MODE 2ND BYTE NOT USED MA 1794 Figure 4 4 Command Register Format RX28 4 4 The function codes bits 8 9 10 are summarized below described in Paragraph 4 1 4 Code Function 000 Fill Buffer 001 Empty Buffer 010 Write Sector 011 Read Sector 100 Not used RX8E Set Density R X28 101 Read Status 110 Write Deleted Data Sector Read Error Register The DRV UNIT SEL bit bit 7 selects one of the two drives upon which the function will be performed AC7 0 Select drive 0 AC7 Select drive The 8 12 bit bit 5 selects the length of the data word AC5 0 12 bit mode selected 5 8 bit mode selected The DEN bit bit 3 for RX28 indicates the density for the function to be performed 0 single 1 double The RX8E RX28 will initialize into 12 bit mo
119. ster overflows if necessary the RX02 control zero fills the remainder of the sector buffer the Done bit is set and an interrupt will occur if the program has enabled interrupts 4 34 Write Sector command to write the contents of the sector buffer onto the disk is moved into the RX2CS The program tests TR and when TR is set moves the desired sector address to the RX2DB TR remains false while the sector address is shifted to the 02 control The control retests TR and when it is again set moves the desired track address register to the RX2DB Again TR is negated The 02 locates the desired track and sector and compares the diskette density against the assigned function density and writes the contents of the sector buffer onto the disk if the densities agree When the write operation is completed the Done bit is set and an interrupt will occur if the program has enabled interrupts A typical disk read operation occurs in the reverse order First the desired track and sector are located and the contents of the sector are read into the sector buffer read sector Then the contents of the sector buffer is unloaded into memory empty buffer In either case the contents of the sector buffer are not valid if either a Power Fail or Initialize follows a fill buffer or read sector function 4 3 1 Register and Vector Addresses The RX211 RXV21 use two registers for communicating with the host computer the command and status register RX
120. suing the command instruction Upon receiving a command instruction while in the Done state the RX8E RX28 enters the Not Done state while the command is decoded Each of the eight functions summarized below requires that a strict protocol be followed for the successful transfer of data status and address information The protocol for each function is described in the following sections summary table is presented below Octal AC 8 9 10 Function 0 0 0 Fill Buffer 0 0 1 Empty Buffer 0 1 0 Write Sector 0 1 Read Sector 1 0 0 Not Used RX8E Set Density RX28 1 0 1 Read Status 1 1 0 Write Deleted Data Sector 1 1 1 Read Error Register NOTE AC bit 11 is assumed to be 0 in the above octal codes since AC bit 11 can be 0 or 1 4 8 4 1 4 1 Fill Buffer 000 For RX8E this function is used to load the 02 sector buffer from the host processor with 64 12 bit words if in 12 bit mode or 128 8 bit words if in 8 bit mode For RX28 this function loads the sector buffer in 12 bit mode with 64 12 bit words for single density or 128 12 bit words for double density in the 8 bit mode the buffer is loaded with 128 8 bit bytes for single density or 256 8 bit bytes for double density This instruction only loads the sector buffer In order to complete the transfer to the diskette another function write sector must be performed The buffer may also be read back by means of the empty buffer function in order to verify the data Upon decoding the
121. ta address mark is written preceding the data rather than the standard data address mark The Density bit associated with the function indicates whether a single or double density deleted data address mark will be written 4 3 3 8 Read Error Code 111 The read error code function implies a read extended status In addition to the specific error code a dump of the control s internal scratch pad registers also occurs This is the only way that the word count register can be retrieved This function is used to retrieve specific information as well as drive status information depending upon detection of the general Error bit 4 4 The transfer of the registers is a DMA transfer The function is initiated by loading the RX2CS with the command and then Done goes false When TR is true the RX2BA may be loaded into the RX2DB and TR goes false The registers are assembled one word at a time and transferred directly to memory Register Protocol Word 1 lt 7 0 gt Definitive Error Codes Word 1 lt 15 8 gt Word Count Register Word 2 lt 7 0 gt Current Track Address of Drive 0 Word 2 lt 15 8 gt Current Track Address of Drive 1 Word 3 lt 7 0 gt Target Track of Current Disk Access Word 3 lt 15 8 gt Target Sector of Current Disk Access Word 4 lt 7 gt Unit Select Bit Word 4 lt 5 gt Head Load Bit Word 4 lt 6 gt lt 4 gt Drive Density Bit of Both Drives Word 4 lt 0 gt Density of Read Error Register Command Word 4 lt 15 8 gt Track Addr
122. ta marks of both densities This diskette should again be completely reformatted 4 1 4 6 Maintenance Read Status 101 for RX28 only This function updates the drive ready and drive density status of the selected drive clears the INIT DONE bit updates the Unit Sel possibly sets the density error bit and leaves the remainder of the RX2ES unchanged The drive density is updated by loading the head on the selected drive without changing head and reading position with the first header and data mark that randomly appears under the head The control will then generate the appropriate number of shift pulses which will transfer the RX2ES error and status register over the interface Upon completion of the RX2ES transfer the control asserts Done to complete the oper ation 4 1 4 7 Read Status 101 for RX8E only Upon decoding this function the RX02 moves the RXES to the RX8E interface register and sets the done flag The RXES can then be read by the transfer data register XDR command The bits are defined in Paragraph 4 1 3 6 NOTE The average time for this function is 250 ms Exces sive use of this function will result in substantially reduced throughput 4 10 4 1 4 8 Write Deleted Data Sector 110 This function is identical to the write data function except that a deleted data mark is written prior to the data field rather than the normal data mark Paragraph 1 5 3 2 RX2ES bit 5 Deleted Data will be set in the interface register
123. ted Bit 4 RX2ES is set Density Error and the RX2ES is moved to the RX2DB If bit 6 RX2CS Interrupt Enable is set an interrupt is initiated If a legal data mark is successfully located and the control and densities agree the control will read data from the sector into the internal buffer If a deleted data address mark was detected the control will set bit 6 RX2ES DD As data enters the internal buffer a CRC is computed based on the data field and the CRC bytes previously recorded A non zero residue indicates that a read error has oc curred and the control sets RX2ES CRC error and bit 15 RX2CS Error The RX211 RXV21 ends the operation by asserting Done and moving the contents of the RX2ES into the RX2DB If bit 6 RX2CS is set an interrupt is initiated 4 40 If the desired sector is successfully located the densities agree and the data is transferred with CRC error Done will be set and if bit 6 RX2CS Interrupt Enable is set the RX211 RXV21 initiates an interrupt 4 3 3 5 Set Media Density 100 This function causes the entire diskette to be reassigned to a new density Bit 8 RX2CS Density indicates the new density The control reformats the diskette by writ ing new data address marks double or single density and zeroing all of the data fields on the diskette The function is initiated by loading the RX2CS with the command Initiation of the function clears RX2ES and Done When TR is set an ASCH
124. tion 101 before checking for errors with the read error register function 111 The SEL bit is present only at the time of the read status function 101 for either drive or at completion of an Initialize for drive 0 It is not necessary to load the drive select bit into the command word when the command is Fill Buffer 000 or Empty Buffer 001 Sector Addressing 1 26 1 32 No sector 0 Track Addressing 0 76 or 1 114g If a read error register function 111 is desired the program must perform this function before a read status function 101 because the content of the error register is always modi fied by a read status function 4 22 10 The instructions STR SDN SER also clear the respective flags after testing so that the software must store these flags if future reference to them is needed after performing one of these instructions 11 Excessive use of the read status function 101 will result in drastically decreased throughput because a read status function requires between one and two diskette revolutions or about 250 ms to complete 42 AND RXVI1 PROGRAMMING INFORMATION This section describes device registers register and vector address assignments programming specifi cations and programming examples for the RX11 RXVII interfaces All software control of the RX11 RXVI1 is performed by means of two device registers the command and status RXCS register and a multipurpose data buf
125. tions respectively These examples are very similar to the RX8E programming examples described in Paragraph 4 1 6 Basically there are two differences between the RX8E and RX28 examples First for the RX28 when a command is transferred in the 8 bit mode of operation it is transferred in two 8 bit words using an XDR to transfer the second command word see location 0225 in Figure 4 14 second for the RX28 there is no parity error check as there is in the RXSE instead there is a density error check gt gt gt Pg 4 5 fu amp tl fue ng 27 281 2222 2275 2224 27285 2225 2257 0211 2212 8213 7214 2215 2216 2217 2222 42214 2222 09293 2224 4225 222 2227 agyi 2232 223 4234 2255 7236 2247 20232 8681 agas 2255 224 2237 dese 2251 2252 2253 2254 5721 5722 6733 6734 6785 5726 5727 2220 1266 5972 1266 3271 6725 5224 1273 274 1275 527 1275 5721 1276 4257 7152 5226 7135 7284 5723 5223 5722 5725 3226 1277 5742 7282 5721 231 15342 5722 1272 5725 5243 6724 7132 6722 332 7221 8371 7552 5255 2278 5225 7222 PROGRAMING EXAMPLES FOR THE RXOB E FLEXIBLE DISKETTE FILLOWING ARE 21 TOT COJE DEFINITIONS 4 YME STANDARD JEVICE CIDE 13 575
126. tor from the disk 0220 R W electronics failed maintenance mode test 0240 Density Error 43 RX211 AND RXV21 PROGRAMMING INFORMATION This section describes device registers register and vector address assignments programming specifi cations and programming examples for the RX211 and RXV21 interfaces All software control of the RX211 RXV21 is performed by means of two device registers the com mand and status register RX2CS and a multipurpose data buffer register RX2DB which have been assigned bus addresses and can be read or loaded The 2 contains all the control circuitry required to read from and write on the disk and to calcu late and verify the CRC It has a buffer large enough to hold one full sector of diskette data 128 or 256 8 bit bytes Information is serially passed between the interface and the RX02 A typical diskette write sequence which is initiated by a user program would occur in two steps Fill Buffer A command to fill the buffer is moved into the RX2CS The Go bit must be set The program tests for TR When TR is detected the program moves the desired word count into the RX2DB TR goes false while the word count is moved to the RX02 The program retests TR moves the bus address into the RX2DB The device now requests bus mastership and DMA s one data word at a time into the RX2DB and shifts it across the 02 data bus serially one 8 bit byte at a time into the sector buffer When the word count regi
127. und but no ID mark found within allowable time span 0150 The header track address of a good header does not compare with the desired track 0160 Too many tries for an IDAM identifies header 0170 Data AM not found in allotted time 0200 CRC error on reading the sector from the disk 0220 R W electronics failed maintenance mode test 0240 Density error 0250 Wrong key word for Set Media Density command 4 12 4 1 6 RX8E Programming Examples 4 1 6 1 Write Write Deleted Data Read Functions Figure 4 11 presents a program for implement ing a write write deleted data or a read function with interrupts turned off IOF The first 3 steps preset the CTRY and STRY retry counters which are set at 10 retries but can be changed to any number Starting at RETRY the program tests for 8 or 12 bit mode type of function and drive Once the command is loaded the program waits in a loop for the controller to respond with transfer request TR When TR is set the sector address is loaded and the AC 15 cleared The program loops while waiting for the controller to respond with another TR When TR is reset the track address is loaded and the AC is cleared again The program loops to wait for the Done condition When the done flag is set the program checks for an error condition indicated by the error flag being set If the 0000 the error is a seek error if bit 11 of the AC is set the error is error Error status from the R
128. upon completion of the function 4 1 4 9 Read Error Code Function 111 The read error code function can be used to retrieve explicit error information upon detection of the error flag Upon receiving this function the RX02 moves error code to the interface register and sets Done The interface register can then be read via an XDR command and the code interrogated to determine which type of failure occurred Paragraph 4 1 5 NOTE Care should be exercised in the use of this function The program must perform this function before a read status because the error register is always modi fied by a read status function 4 1 4 10 Power Fail There is no actual function code associated with power fail When the RX02 senses a loss of power it will unload the head and abort all controller action All status signals are invalid while power is low When the 02 senses the return of power it will remove Done and begin a sequence to Move drive 1 head position mechanism to track 0 Clear any active error bits Read sector of track 1 of drive 0 into the buffer Set Initialize Done bit of the RX2ES after which Done is again asserted There is guarantee that information being written at the time of a power failure will be retrievable However all other information on the diskette will remain unaltered INIT IOT is a method of aborting an incomplete function Paragraph 4 1 2 7 4 1 5 Error Recovery 4 1 5 1
129. us function requires between one and two diskette revolutions or about 250 ms to complete 4 33 4 2 6 Error Recovery There are two error indications given by the RX11 RXVI1 system The read status function Para graph 4 2 3 5 will assemble the current contents of the RXES Paragraph 4 2 2 6 which can be sampled to determine errors The read error code function Paragraph 4 2 3 7 can also be used to retrieve explicit error information The RX11 RXVI1I interface register can be interrogated to deter mine the type of failure that occurred A list of error codes follows NOTE read status function is not necessary if the DRV RDY bit is not going to be interrogated because the RX2ES is in the interface register at the completion of every function Octal Code Error Code Meaning 0010 Drive 0 failed to see home on Initialize 0020 Drive 1 failed to see home on Initialize 0040 Tried to access a track greater than 77 0050 Home was found before desired track was reached 0070 Desired sector could not be found after looking at 52 headers 2 revolutions 0110 More than 40 us and no SEP clock seen 0120 preamble could be found 0130 Preamble found but no ID mark found within allowable time span 0140 CRC error on what appeared to be a header Error is not asserted 0150 The header track address of a good header does not compare with the desired track 0160 Too many tries for an IDAM identifies header 0200 CRC error on reading the sec
130. ve the CPU is preferred The ac power cord is about 2 7 m 9 ft long 2 1 3 AC Power 2 1 3 1 Power Requirements The 02 is designed to use either 60 Hz a 50 Hz power source The 60 Hz version will operate from 90 128 Vac without modifications and will use less than 4 A operating The 50 Hz version will operate within four voltage ratings and will require field veri fication modification to ensure that the correct voltage option is selected The voltage ranges of 90 120 Vac and 184 240 Vac will use less than 4 A operating The voltage ranges of 100 128 Vac and 200 256 Vac will use less than 2 A Both versions of the RX02 will be required to receive the input power from an ac source e g 861 power control that is controlled by the system s power switch 2 2 2 1 3 2 Input Power Modification Requirements 60 Hz version of the 02 uses the H771 A power supply and will operate on 90 128 Vac without modification To convert to operate on a 50 Hz power source in the field the H771 A supply must be replaced with an H771 C or D Figure 1 4 and the drive motor belt and drive motor pulley must be replaced Figure 1 5 The H771 C operates on a 90 120 Vac or 100 128 Vac power source The H771 D operates on a 184 240 Vac or 200 256 Vac power source To convert the H771 C to the higher voltage ranges or the H771 D to the lower voltage ranges the power harness and circuit breaker must be changed See Figure 2 3 for the appropriat

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