Pause request processing for data traffic modification
Contents
1. 006 U S Patent May 10 2011 Sheet 10 of 10 US 7 941 575 B2 Scenario Hane New Scenario 1 Direction far traffic changes Prom Initiator 1030 1010 Ti Globali Rules amp lt Click bere to add an event gt 1020 Click here to add a sequencen FIG 10a No action specified for the event Any Oword from Initiator in Gobel Rides Chick here to jump to the problem Scenario Nane New Scenario 1 ap i Direcrion for traffic changes Frem Initiator 1030 1010 E Global Rules 1 Ch 3 Waic for Any Dward from Initiator lt Clack here te add an action 3 1 1040 1050 u lt Click here to add a sequence gt FIG 10b 1030 1010 1060 1040 mre FIG 10c 1030 ze Be an evens 6 1010 Stare 6 Wait for CRO Error from Initiator then BNC Output Send Fouitive Pulae 1070 FIG 10d US 7 941 575 B2 1 PAUSE REQUEST PROCESSING FOR DATA TRAFFIC MODIFICATION CROSS REFERENCE TO RELATED APPLICATIONS This application claims priority to U S Patent Application Ser No 60 779 039 entitled Data Capture Method And Apparatus which was filed by Roy A et al on Mar 3 2006 U S Patent Application Ser No 60 779 179 entitled Pro tocol Traffic Modification Method And Apparatus which was filed by Fouxman E et al on Mar 3 2006 U S Patent Application Ser No 60 778 834 entitled Cross Platform Trigger Method A2. Process data 208 Send pause request primitive to host 712 Send data to host Z10 Send acknowledge pause request primitive to target Buffer data from host oS Z14 Receive acknowledge pause request primitive from host Receive in progress primitive from target Send buffered data to target 722 Send receive in progress primitive to host FIG 7 U S Patent IG Ye Save continue primitive context May 10 2011 Sheet 8 of 10 US 7 941 575 B2 Rant Start Receive primitive from targe 4 Is a continue primitive 806 No EE LEN Buffer data R Send continued hold request to target 820 Set holding state 822 Process data 812 Send data to host H Receive data from host 816 Send buffered data to target 832 Isa continued hold request 818 Re establish continue primitive context with host 830 Recall saved continue primitive context in a holding state 824 Send acknowledge pause request primitive to host 826 US 7 941 575 B2 Sheet 9 of 10 May 10 2011 U S Patent 6 8 Z 6 8 L 96 3 9 y C 0 akg SpJomp ap 2 006 96 5 3 9 C L 0 ag 2222 daad spsomp cos E6 DIA 9 v 0 9 0000 2222 9999 VVVV spiomp
3. cation device senses such a receiving message and there is no continued state to re establish the state machine 400 propa gates the receiving message to the host and transitions to a PRIM_EXIT state 406 During the PRIM_EXIT state 406 the data traffic modification device sends any data that may have been buffered When the buffer has been emptied the state machine 400 transitions back to the PRIM_IDLE state 402 In another example the SATA host may send a pause request after sending one or more primitives In this case the state machine 400 starts in the PRIM_IDLE state 402 During the PRIM_IDLE state the data traffic modification device may receive a continued primitive message e g a R_IP R_IP CONT sequence from the target The data traffic modification device may also receive a continued pause request from the host e g a HOLD HOLD CONT sequence Upon detection of the continued pause request the state machine 400 propagates the continued pause request to the target stores the context of the continued primitive mes sage from the target and then transitions to the PRIM_PRIM state While in the PRIM_PRIM state the data traffic modi fication device generates a series of hold acknowledgement messages and sends them to the host The host may then send a single pause request to break the continued pause request and to resume propagating the data stream In some embodi ments the SATA primitives that may be used to break
4. 3 2006 and the contents of which are incorporated herein by reference In some embodiments the editor GUI 1000 may be capable of saving a scenario description as binary data locally and or to a data traffic modification device In some embodiments the editor GUI 1000 may be capable of saving the scenario definition in a human readable format e g text XML CSV HTML tagged and the like either locally or to a data traffic modification device In some embodiments the editor GUI 1000 may be capable of retrieving scenario definitions from a data traffic modification device In some embodiments the editor GUI 1000 may be capable of synchronizing saved versions of scenario definitions between the computer run ning the editor GUI 1000 and the data traffic modification device For example a computer running the editor GUI 1000 may hold a version of a scenario that is at a different revision level than a scenario that is stored in a data traffic modification device In some embodiments the editor GUI 1000 may pro vide the user with a method to synchronize the editor GUI 1000 and data traffic modification device to cause identical versions of a scenario to exist in both locations In some US 7 941 575 B2 13 embodiments the editor GUI 1000 may merge or otherwise reconcile the differences between two or more scenarios In some embodiments the editor GUI 1000 may be capable of querying the data modification device to determine the revi
5. At step 710 processed data is sent to a host Control then passes back to step 702 to receive additional primitives from the target If at step 704 the primitive received at step 702 is a pause request primitive then the process continues at step 706 At step 706 the pause request primitive is allowed to bypass data processing steps At step 712 the unprocessed pause request primitive is sent to the host At step 714 the data traffic modification device begins to buffer data received from the host in a FIFO If at step 716 a acknowledge pause request primitive is received from the host then control passes to step 720 If at step 716 an acknowledge pause request primitive is not received from the host then control passes to step 718 Dur ing step 718 the acknowledge pause request primitive is sent to the target If at step 720 the data traffic modification device does not receive a read in progress primitive from the target device 20 25 30 35 40 45 50 55 60 65 10 then control passes to step 718 If at step 720 a read in progress primitive is received from the target then the process continues at step 722 During step 722 data buffered in the FIFO if any during step 714 is sent to the target At step 724 a read in progress primitive is sent to the host In some embodiments this may signal the host that the target or the data traffic modification device is ready to accept data FIG 8 is a
6. SATA standard various embodiments may use various versions of the SATA protocol e g SATA 2 0 and or protocols other than SATA In some examples the configuration 100 may use a SATA compliant protocol such as SAS serial attached SCSI small computer system interface and or SATA Tun neling Protocol STP In some embodiments the data traffic modification device 105 may also be capable of using a com bination of protocols For example the configuration 100 may be implemented with the SAS initiator 10 using SAS and the target 115 using SAS STP or SATA In some further examples a hub may be included to provide connections between at least one initiator 110 and at least one target 15 where each connection may use a combination of protocols Further aspects and examples relating to data traffic modifi cation are described in U S provisional patent application 60 779 264 entitled Impairment and Monitoring Apparatus and Method by Roy A et al which was filed Mar 3 2006 and the contents of which are incorporated herein by refer ence 20 25 30 35 40 45 50 55 60 65 4 FIG 2 is a block diagram 200 depicting an exemplary data flow through the data traffic modification device 105 of FIG 1 Communications data may enter the data traffic modifica tion device 105 through an initiator port in 202 or through a target port in 204 Data entering though the initiator port in 202 then passes to a fir
7. a continued state may include but are not limited to HOLD HOLDA PMREQP PMREQS RERR RIP R OK R_RDY SYNC WTRM or XRDY The state machine 400 responds by propagating the message to the target and tran sitioning to a PRIM_SCND state 408 During the PRIM_ SCND state 408 the data traffic modification device recalls the stored context information and uses that stored context information to reestablish the continued target context that 20 25 30 35 40 45 50 55 60 65 8 was in place prior to the arrival of the continued pause request from the host Once the prior target context is reestablished the state machine 400 transitions back to the PRIM IDLE state 402 In another example the SATA host may send a pause request after sending data to the target as will be further illustrated by FIG 6 and FIG 8 In this case the state machine 400 starts in the PRIM_IDLE state 402 where the data traffic modification device propagates data between the host and target During this state the target sends a continued receiving message e g a R_IP R_IP CONT sequence and the host sends data If the data traffic modification device detects that the host has sent a continued pause request the data traffic modification device propagates that continued pause request to the target stores the current context infor mation and transitions to the PRIM_PRIM state 404 During the PRIM_PRIM state 404 the data traffic modi
8. computer e g the editor GUI 1000 of FIG 10 to load the scenario from the data traffic modification device to view or edit the scenario on the second computer In another illustrative example a data traffic modification device may be used in a manufacturing test environment For example a data traffic modification device may be connected ina SATA link between a test computer acting as a SATA host and a SATA disk drive in a disk drive testing system A trigger input of the data traffic modification device may be connected to a programmable logic controller PLC that is controlling automated aspects of the manufacturing test process The data traffic modification device may also connect to a development computer running an editor GUI e g the editor GUI 1000 across an Ethernet network to allow a test engineer to remotely develop and or to deploy scenarios to the data traffic modification device In some implementations the test engi neer may use the editor GUI to connect to one or more data modification devices and perform a synchronization process to distribute a common synchronized version of a scenario definition to the manufacturing test environment The test engineer may use the editor GUI to read and record informa tion about the scenarios that have been deployed to the data traffic modification device and that data may be relayed to a database that may be queried to determine which version of the scenario was used to test a disk
9. computer running the editor GUI 1000 may communicate through a universal serial bus USB IEEE488 IEEE1384 RS 232 RS 422 RS 488 or any other such serial or parallel communications bus or combinations thereof In some embodiments the editor GUI 1000 may save the binary or human readable scenario data in a compressed format In some embodiments the data traffic modification device may be used as a stand alone instrument For example once a scenario definition has been saved to the data traffic modifi cation device the data traffic modification device may be disconnected from the computer running the editor GUI 1000 Examples of using scenario definitions in a stand alone data traffic modification device are described in further detail in U S provisional patent application 60 779 179 entitled Protocol Traffic Modification Method and Apparatus by Fouxman E et al which was filed Mar 3 2006 and the contents of which are incorporated herein by reference Although various embodiments have been described fur ther embodiments are possible For example some embodi ments may be implemented with a stand alone data traffic modification system a waveform processing system a digital storage oscilloscope a protocol analyzer or logic analyzer Some implementations may include two or more channels to acquire multiple signals substantially simultaneously Examples of various features and operational aspects of some implementations fo
10. d illustrate an exemplary editor graphical user interface GUI 1000 for viewing and editing data modifica tion scenarios The editor GUI 1000 may be implemented as a software program running on a computer In FIG 10a the editor GUI 1000 includes an adaptive text interface 1010 a scenario description 1020 and a status indicator 1030 In some embodiments the adaptive text interface 1010 may be capable of guiding the user through the scenario development process by displaying the scenario description as a collection of English or other written language phrases In some embodiments the adaptive text interface 1010 may provide a collection of editable fields or regions that the user may activate to full in information that defines a scenario In some embodiments when the user invokes an editable region the adaptive text interface 1010 may respond by presenting dia log boxes wizards entry blanks dropdown list boxes or other user input controls by which a user may enter data into a computer application In the depicted example the user has opened a new scenario template but has not yet entered any information into it A scenario that configures a data traffic modification device to do nothing may be considered to be a valid configu ration In some embodiments the editor GUI 1000 may check the validity of scenarios in real time as the user edits the configuration In some embodiments the editor GUI 1000 may check the validity of scenarios
11. one or more directions In some embodiments the data may be modified to purposely alter the communications between the SATA initiator 110 and the SATA target 115 In the depicted example the configuration 100 includes the data traffic modification device 105 the initiator 110 the target 115 anda protocol analyzer 120 The data traffic modi fication device includes a first port 125 anda second port 130 In this example the ports 125 130 are compliant with the SATA standard and include two pairs of conductors in order to allow for bidirectional communications The first port 125 is in communication with a first channel 135 of the protocol analyzer 120 and the second port 130 is in communication with a second channel 140 of the protocol analyzer 120 The first port 135 is also in communication with the initiator 10 and the second port 140 is also in communication with the target 115 In the configuration 100 communications between the SATA initiator 110 and the SATA target 115 may be modified by the data traffic modification device 105 and traced by the protocol analyzer 120 This configuration may allow a tech nician to confirm that the data traffic modification device 105 has been configured correctly or may allow a technician to observe how the SATA initiator 110 or SATA target 115 respond when either receives modified data While the exemplary configuration 100 has been described in terms of communications according to a version of
12. sion level of a scenario that may be saved on the data modi fication device In some embodiments the editor GUI 1000 may record information relating to one or more scenarios e g scenario name revision level creation data last modi fied date on one or more data traffic modification devices In some embodiments scenario data may be saved in a manner that may allow the data to be correlated to manufacturing data e g lot codes serial numbers and dates of manufacture For example a database may be queried in order to determine which version of a scenario was used to test a particular batch of manufactured disk drives In some embodiments scenario definitions may be deployed to a data traffic modification device through the use of a portable storage device For example a scenario definition may be saved to a floppy disk or a USB drive When the user inserts the disk or drive into a data traffic modification device the data traffic modification device may then provide a method for copying the scenario definitions on the disk or drive to the data traffic modification device In some embodiments the data traffic modification device and the computer running the editor GUI 1000 may commu nicate through a common Ethernet network and this commu nications link may allow the editor GUI 000 to save and or retrieve scenario data to or from the data traffic modification device In some embodiments the data traffic modification device and the
13. small signal levels in the correct time intervals As data rates increase margins of error for the signal level timing tend to decrease Likewise operating frequencies for some analog signal processing systems continue to increase along with advances in telecommunication technologies for example Various test and measurement equipment may be used to verify signal integrity in analog and digital systems For example oscilloscopes may be used to measure analog wave forms and protocol analyzers may be used to monitor data in digitally formatted signals Other waveform processing equipment may provide signal processing operations that may include but are not limited to acquisition e g sam pling monitoring and or modification e g filtering time shifting amplification of analog and or digital signal wave forms Ina typical data transfer a data source device may transmit data to be received by a target device Data transfers may be performed according to electrical and timing parameters specified by a communication protocol Representative examples of well known serial communication protocols include Fibre Channel SATA Serial Advanced Technology Attachment SAS serial attached SCSI small computer sys 20 25 30 35 40 45 50 55 60 65 2 tem interface and SATA Tunneling Protocol STP Com munication errors can occur when data transfers do not meet the protocol specifications SUMMARY Ap
14. substitution upon any frame that may be encountered after the substitution data has been sampled In some embodiments a single trigger may invoke the sampling and substitution processes In some embodiments the sampling process and substitution process may be invoked by independent triggers In some embodi ments one or more of the bits of sampled data may be used in the substitution process In some embodiments the sampled data may be modified by incrementing decrementing bit shifting bit masking by performing bitwise operations with the sampled and target data or by other methods for modify ing a collection of bits in a data traffic modification device or by combinations thereof FIG 9c illustrates an example of a substitution process that may be performed on buffered data In this example the data traffic modification device has taken the data sampled from dword 4 and has used it to replace the data originally found in dword 1 Although dword I arrived in the buffer 900 prior to dword 4 the data traffic modification device may still perform a substitution process upon dword I or any other dword that is held in the buffer 900 After a substitution process such as those illustrated by FIGS 9a 9c the data frame may no longer contain valid CRC data The data traffic modification device may calculate valid CRC data based upon the contents of the frame and replace the original CRC data with the valid calculated CRC data FIGS 10a
15. 1 Both HOLD or 2 Local HOLD 2 There was a 3 ELSE CONT in effect 2 No more HOLD there is no primitive condition to re establish 3 ELSE PRIM_PRIM PRIM_EXIT 404 406 1 Local HOLD 1 Local 1 No more HOLD 1 Local HOLD HOLD must re establish 2 ELSE primitive condition 2 There was a CONT PRIM_SCND in effect must PRIM_CONT on re establish it 410 FIG 4 U S Patent May 10 2011 Sheet 5 of 10 US 7 941 575 B2 500 510 520 qn ent by fusion itiator Port 2 0 Re ars E 60 PRP RIP Data CONT RIP Data B CONT Data C POR IP ARP DataD PKR IP POR IP Data RIP 1 Data F HOLD Data 6 CONT HOLD DataH_ OXHOLD conr J SJHOLDAPOXKHOLD exo ____ 1SCONT 001000 XXHOLD XXHOLD ___18PO HOLDA 901000 19KHOLDA XXHOLD ___21POHOLDA RPJ 23 X HOLDA CONT 24OXHOLDA PAR IP 250 ORP _261086 XRP 27jDataN _ ARP ___ 28 Data O __ PARIP ed U S Patent May 10 2011 Sheet 6 of 10 US 7 941 575 B2 ta D Datel OL g FIG 6 U S Patent May 10 2011 Sheet 7 of 10 US 7 941 575 B2 Receive primitive from target 7 Pause request primitive 704 Bypass data processing 706
16. Firm Gordon Kessler US 2007 0206496 Al Sep 6 2007 57 ABSTRACT Related U S Application Data Apparatus and associated systems and methods may relate to 5 co a data traffic modification system that may include a process 60 Provisional application No 60 779 180 filed on Mar ing module to handle SATA compliant data transfers in which 3 2006 provisional application No 60 779 039 filed a source device or a target device issues requests to pause and on Mar 3 2006 provisional application No subsequently to resume the data transfer In various imple 60 779 179 filed on Mar 3 2006 provisional mentations a data traffic modification device may selectively application No 60 778 834 filed on Mar 3 2006 modify data traffic upon the occurrence of a predetermined provisional application No 60 779 084 filed on Mar condition In one illustrative example if a target device for the 3 2006 provisional application No 60 779 085 filed data transfer issues a pause request e g to prevent a buffer on Mar 3 2006 provisional application _No overflow the data traffic modification device may generate a 60 779 264 filed on Mar 3 2006 provisional pause acknowledge signal to the target device within a application No 60 892 093 filed on Feb 28 2007 response time specified by the protocol In another illustrative example ifa source device for the data transfer issues a pause 51 Int Cl request the data traffic modification device ma
17. For example the data traffic modification device 105 may com municate with a portable computer network server or other device using point to point communication in which a mes sage is transported directly from the source to the receiver over a dedicated physical link e g fiber optic link point to point wiring and daisy chain Other embodiments may transport messages by broadcasting to all or substantially all devices that are coupled together by a communication net work for example by using omni directional radio frequency RF signals while still other embodiments may transport messages characterized by high directivity such as RF sig nals transmitted using directional i e narrow beam anten nas or infrared signals that may optionally be used with focus ing optics Still other embodiments are possible using appropriate interfaces and protocols such as by way of example and not intended to be limiting RS 232 RS 422 RS 485 802 11a b g Wi Fi Ethernet IrDA FDDI fiber distributed data interface token ring networks or multiplex ing techniques based on frequency time or code division Some implementations may optionally incorporate features such as error checking and correction ECC for data integ rity or security measures such as encryption e g WEP and password protection In some embodiments each memory may be programmed with the same information and be initialized with substan tially identical informatio
18. The target may issue a pause request for example if it is receiving data faster that it can process the data In the depicted figure the primi an 5 40 45 55 65 6 tive detect module 209 is configured to detect and react to pause requests from the target In operation the primitive detect module 209 may react by signaling the hold handler 238 to generate a pause request acknowledge signal back to the target This process may allow a pause acknowledgement signal to be sent to the target while avoiding the delay asso ciated with propagating through the buffer FIFOs 234 236 In this example data being transferred from the initiator may continue to be sent until the initiator receives and responds to the pause request after the pause request propagates through one of the FIFOs 234 236 During this time the valid data sent by the initiator may be buffered in one of the FIFOs 234 236 at least until the target breaks the pause state and the data transfer resumes In another illustrative example an initiator e g host device may issue a pause request After the pause request is issued some time may pass while the pause request propa gates though the block diagram 200 e g from the initiator port in 202 to the first input processing module 208 through one of the FIFOs 234 236 and to the target port out 240 As such the target may acknowledge the pause request after some delay that in some examples may exceed the
19. US007941575B2 az United States Patent 10 Patent No US 7 941 575 B2 Roy et al 45 Date of Patent May 10 2011 54 PAUSE REQUEST PROCESSING FOR DATA 56 References Cited TRAFFIC MODIFICATION U S PATENT DOCUMENTS 75 Inventors Andrew Roy Erie CO US Amit 7 523 235 B2 4 2009 Nemazie etal 710 74 Bakshi Sunnyvale CA US Shlomi 2006 0267798 Al 11 2006 Jacobsen et al Krepner Sunnyvale CA US Eugene 2007 0005838 Al 1 2007 Chang et al Fouxman Mountain View CA US 2007 0189176 Al 8 2007 Milne et al 370 241 Dmitry Karpoy San Jose CA US 2007 0220357 Al 9 2007 Vedanabhatla et al 714 43 Douglas Lee Milpitas CA US OTHER PUBLICATIONS 73 Assignee LeCroy Corporation Chestnut Ridge SAS Infusion Error Injection Platform for Serial Attached SCSI and NY US Serial ATA LeCroy Protocol Solutions Group Believed to have been publicly available as of Dec 21 2004 2 pages Notice Subject to any disclaimer the term of this SAS Infusion User Manual Error Injection Platform for Serial patent is extended or adjusted under 35 Attached SCSI and Serial ATA User Manual Version 1 21 for Soft U S C 154 b by 653 days ware Version 1 2 LeCroy Protocol Solutions Group Feb 2007 113 pages 21 Appl No 11 681 537 Catan 22 Filed Mar 2 2007 Primary Examiner Cheng Yuan Tseng 65 Prior Publication Data 74 Attorney Agent or
20. ata that fulfills the trigger condition sending the selectively modified data stream to a target device over a second SATA compliant data link receiving a SATA compliant hold request signal compris ing a SATA HOLD primitive from the target device generating a SATA compliant hold acknowledge signal comprising a SATA HOLDA primitive to send to the target device in response to the received hold request signal sending the received hold request signal to the source device buffering the data stream after receiving the hold request signal and at least until the source device interrupts the data stream in response to the hold request signal receiving a resume signal from the target device to resume transmission of the data stream and sending the buffered data to the target device in response to receiving the resume signal 2 The method of claim 1 further comprising restoring a context of the data stream in response to receiving the resume signal and before resuming transmission of the data stream 3 The method of claim 1 wherein the trigger condition comprises a user specified data value in the data stream 4 The method of claim 1 further comprising sending the hold acknowledge signal to the target device within up to 20 double words after receiving the hold request signal 5 The method of claim 1 further comprising monitoring signals from the target device to detect the hold request signal 6 The method of claim 1 wherein se
21. block diagram of an exemplary process 800 for re establishing a context in a data traffic modification device The process begins at step 802 which could be entered auto matically upon power up in response to a software request in response to an electrical signal or other methods for initiating a software process in a data traffic modification device or combinations thereof At step 804 a primitive is received from a target If at step 806 the primitive is determined to be a continue request primitive then control passes to step 808 At step 808 the data traffic modification device saves the context of the continue request primitive For example the continue request primitive may be part of a continued read in progress primitive combination of messages In this case the data traffic modification device would save information that would allow the data traffic modification device to recall the contin ued read in progress primitive state After this information is saved control passes to step 810 If at step 806 the primitive received from the target is not a continue request primitive then control passes to step 810 At step 810 the data traffic modification device begins to buffer data from the target in a FIFO At step 812 the data traffic modification device may process of otherwise modify data from the host in a manner possibly such as that described by blocks 212 214 220 228 and 236 of FIG 2 At step 814 the processed data is
22. chanism may remain active and it may try clear data from the receiving queue before sending a new request Examples of restoring a software communications layer are described in further detail in U S provisional patent application 60 779 085 entitled Communication Flow Recovery Method and Apparatus by Karpov D which was filed Mar 3 2006 and the contents of which are incorporated herein by reference In an illustrative example the data traffic modification device may be used in a laboratory environment For example a user may edit a scenario with an editor GUI running on a first computer e g the editor GUI 1000 of FIG 10 The GUI may provide an adaptive text interface to assist the user while editing the scenario The editor GUI may also display a visible indication of the validity of the scenario substantially in real time as the user enters each edit into the editor GUI 1000 The scenario may be defined for use on a data traffic modification device The user may disconnect the communications link to the data traffic modification device to operate the data traffic modification device as a stand alone instrument In some examples the user may connect the data traffic modification device between a SATA host and a SATA target In some embodiments a trigger output of a data traffic modification device may also be connected to a trigger input of a protocol analyzer Although a protocol analyzer is described in this example the tri
23. d transmits them to the US 7 941 575 B2 9 target During cycles 9 12 the initiator continues to send data primitives The traffic modification device buffers these primitives until the target device breaks the continued HOLD at cycles 19 21 At cycles 21 23 the traffic modification device breaks the continued HOLD it has established with the initiator and at cycle 23 the data traffic modification device begins to empty its FIFO by transmitting buffered data to the target At cycle 27 the FIFO has been emptied and the data traffic modification device sends a pair of ALIGN O primi tives for example to keep the data line active until the Data M primitive sent by the initiator in cycle 26 can be sent to the target in cycle 29 FIG 6 illustrates a table 600 that depicts an exemplary communications session among a SATA initiator shown in a column 610 a data traffic modification device s initiator port shown in a column 620 a data traffic modification device s target port shown in a column 630 and a SATA target shown in a column 640 It should be noted that this table does not represent any particular time scale and is intended to be only a general depiction of one possible flow of commu nications In this example the initiator is sending data during cycles 1 3 and then sends a HOLD HOLD CONT sequence during cycles 4 6 The data traffic modification device responds by storing the current context that it is in a conti
24. data traffic modification device 305 In this example the SAS host 310 is connected to the data traffic modification device 305 the data traffic modi fication device 305 is connected to the SAS expander 325 and the SAS expander 325 is connected to the SAS device 315 FIG 4 illustrates a flow diagram of an exemplary state machine 400 used in a data traffic modifier In one example a SATA host may be sending data to a SATA target when the SATA target sends a pause request as will be further described with reference to FIG 5 and FIG 7 The state machine 400 starts in a PRIM_IDLE state 402 During this state the data traffic modification device propagates data between the host and the target In the depicted example the host is sending data to the target If the data traffic modifica tion device detects that the target has sent a pause request e g a HOLD primitive the state machine 400 responds by propagating the pause request to the host and transitioning to a PRIM_PRIM state 404 During the PRIM_PRIM state 404 the data traffic modification device generates a series of hold acknowledgements e g a series of HOLDA primi tives and sends them to the target and buffers any data that the host sends until the host acknowledges the pause request When the target is once again able to receive data the target may send a receiving message e g a R_IP primitive or a R_IP R_IP CONT sequence When the data traffic modifi
25. drive associated with a particular serial number or lot code A supervisory computer may use a software control layer SCL to connect to one or more data traffic modification devices in the manufacturing test environment The PLC may connect the disk drive to the data traffic modification device trigger the host computer to write data to the disk drive and send a trigger to the data traffic modification device during the testing process The supervisory computer may monitor the activity of the data traffic modification device and provide a link between the data traffic modification device and a manufacturing resource planning MRP system Ifthe communications link between the supervisory computer and data traffic modification device is interrupted the SCL may attempt to recover the commu nications link in order to allow the MRP system to continue monitoring the data traffic modification device Various embodiments may include aspects of a computer The essential elements of a computer are a processor for executing instructions and one or more memories for storing instructions and data Suitable processors for the execution of a program of instructions include by way of example both general and special purpose microprocessors which may include a single processor or multiple processors in combi nation The processor and the memory can be supplemented 0 a 5 40 45 50 65 16 by or incorporated in ASICs applicatio
26. eam com prises signals compliant with a version of a serial attached SCSI small computer serial interface protocol 17 The method of claim 13 wherein the target device comprises one or more electronic data storage devices 18 The method of claim 13 wherein the input module is connectable to a source device through a data bus expander device 19 The method of claim 13 wherein the output module is connectable to a target device through a data bus expander device 20 The method of claim 13 further comprises sending a pause acknowledgement signal to the source device within a predefined response specification after receiving the pause request signal 21 The method of claim 20 wherein the predefined response specification corresponds to receiving up to a threshold quantity of data in the data stream after receiving the pause request signal 22 The method of claim 13 wherein the threshold quantity of data is 20 double words 23 A method comprising selectively modifying data traffic being conveyed in a bidi rectional data transfer between a source device and a target device by monitoring and sampling the data traffic and modifying at least one bit in the data traffic in response to a detected trigger condition at least one bit to be modified is received in a buffer before receiving data that fulfills the trigger condition the data traffic in the data transfer comprising state information for the target device storing the s
27. eck whether it can read at least 1 byte of data If there is no data in the receiving buffers then the communication flow is considered restored and the request to the data traffic modi fication device to transmit the desired data is sent If upon checking the buffers it is determined that the SCL can read at least one byte from the receiving buffers the SCL will try to receive read and discard any data that the device might be sending that is left over from the disconnected communication When SCL determines that there is no longer any data in the receiving queue to read during some specified timeout reached the state of line silence the communica tion flow is considered restored and the new request is sent to the data traffic modification device to transmit the desired data In some implementations the physical connection may once again be lost during this process of cleaning the receiving queue before sending the new request In such a case even if the SCL considers the communication line to be clear some data will remain in the device sending queue and will be sent to the SCL after the physical connection is recov ered In order to confirm proper operation the SCL may check whether a new data response from the device has the same attributes as the request sent to the device from the SCL If not this received data is preferably discarded and the request may be reported as having failed The communication flow recovery me
28. fication device generates and sends a series of hold acknowledgement messages to the host If the data traffic modification device then detects that the host has sent a command primitive to break the continued pause request the state machine 400 propagates the primitive to the target and transitions to the PRIM_SCND state 408 During the PRIM_SCND state the data traffic modification device recalls the previously stored target context information and uses that information to rees tablish the previous context Since the previous context was a continued command the state machine 400 transitions to a PRIM_CONT state 410 During the PRIM_CONT state 410 the data traffic modification device sends a continuation request to the target to reestablish the continued character istic of the previous target context The state machine 400 then transitions to the PRIM_EXIT state 406 to send any buffered data that may be in the data traffic modification device and then returns to the PRIM_IDLE state 402 Insome embodiments the series of hold acknowledgement statements sent during the PRIM_PRIM state may be replaced by a continued hold acknowledgement message sequence followed by a series of scrambled keep alive messages e g a HOLDA HOLDA CONT XXX HOLDA XXX HOLDA sequence FIG 5 illustrates a table 500 that that depicts an exemplary communications session among a SATA initiator shown in column 510 a data traffic modification de
29. fined condition wherein at least one bit to be modified is received in the buffer before receiving data that causes the signal indicating the occurrence of the predefined condition and to transmit the selectively modified data stream from an output module wherein the input module is connectable to a source device and the output module is connectable to a target device monitoring data in the received data stream detecting in the monitored data a SATA compliant signal comprising a HOLD primitive to request a pause in the data stream generating a SATA compliant signal comprising a HOLDA primitive to acknowledge the pause request signal pausing the transmission of the selectively modified data stream in response to the pause request signal identifying a state instruction most recently received by the data traffic modification device before receiving the pause request signal storing the identified state instruction and before resuming transmission of the data stream sending the stored state instruction to the source device to rees tablish the stored state of the data stream 14 The method of claim 13 wherein the step of sending the stored state instruction to the source device comprises con secutively sending the stored state instruction at least twice to reestablish the stored state 15 The method of claim 13 wherein the version of the SATA protocol is compatible with SATA 2 0 16 The method of claim 13 wherein the data str
30. gger output of the data traffic modification device may be connected to a variety of external devices which include but are not limited to oscilloscopes power supplies digital multi meters spectrum analyzers waveform processing devices automation systems and the US 7 941 575 B2 15 like In some examples the user may configure the data traffic modification device to send a trigger output whenever it detects a continued pause request being sent across the SATA link When the data traffic modification device detects this condition it may respond by performing several actions The data traffic modification device may stimulate the trigger output as defined by the user in the editor GUI The data traffic modification device may save a context of the communica tions link prior to the arrival of the continued pause request and buffer any data sent from the host or target prior to the host or target sending a hold acknowledgement message The trigger output may cause the protocol analyzer to log all the data primitives that pass through the SATA link after the data traffic modification device detects the continued pause request Ifthe data traffic modification device receives a pause cancellation message the data traffic modification device may respond by sending any buffered data and reestablishing the context of the SATA link prior to resuming the data trans fer The use may also edit the scenario with the editor GUI running on a second
31. module 222 state machine may be configured to cooperate with the event logic module 220 to modify e g add to ignore remove and or replace some or all of the bits in a frame of data the data stream The data is then sent to a substitution module 224 The substitution module 224 may cooperate with the sequencer module 222 to selectively modify one or more bits within a data frame for example based on operation of the state machine Such substitutions may be performed for example in order to inject an error to test the response of the initiator 110 and or the target 115 US 7 941 575 B2 5 In some implementations the data traffic may have data frames that include CRC cyclical redundancy check data which may be used to verify the integrity of the data that is received When the substitution module 224 modifies data in the data frame the CRC for that frame may be incorrect for the modified data frame A CRC generation module 226 may for example recalculate valid CRC data for the frame and substitute this recalculated CRC data for the original CRC data in the data frame Examples of processes for data sub stitution in a data traffic modification device are described in further detail in U S provisional patent application 60 779 039 entitled Data Capture Method and Apparatus by Roy A et al which was filed Mar 3 2006 and the contents of which are incorporated herein by reference Control then passes to a scrambler m
32. n ued R_IP relaying the HOLD sequence to the target device during cycles 6 8 and by generating a series of HOLDA frames depicted by shaded cells as an acknowledgement to the initiator starting at cycle 8 At cycle 12 the initiator breaks the continued HOLD by sending a single HOLD primitive after which the initiator resumes transmission of data frames during cycle 13 The data traffic modification device responds by reestablishing the previously saved context by recalling that it was in a continued R_IP state and transmitting a R_IP R_IP CONT sequence to the initiator during cycles 17 19 FIG 7 illustrates an exemplary block diagram depicting a process 700 for handling a pause request from a SATA target in a data traffic modification device for example the process illustrated by FIG 5 The process begins at step 701 which could be entered automatically upon power up in response to a software request in response to an electrical signal or other methods for initiating a software process in a data traffic modification device or combinations thereof At step 702 a primitive is received from a target If at step 704 the primi tive received at step 702 is not a pause request then control passes to step 708 At step 708 data is processed For example this may mean that the data received from the target may be processed or otherwise modified in a manner for example such as that described by blocks 212 214 220 228 and 236 of FIG 2
33. n specific integrated circuits Generally a processor will receive instructions and data from a data store such as a read only memory ROM a random access memory RAM or both Generally a computer will also include or be operatively coupled to communicate with one or more mass storage devices for storing data files Storage devices suitable for tangibly embodying computer program instructions and data may include volatile and or non volatile memory NVM which may include but is not limited to semiconductor memory devices e g RAM EPROM EEPROM NAND flash NOR flash thumb drives magnetic disks e g hard disc drives magneto optical and or optical media e g CD DVD In some implementations one or more user interface fea tures may be custom configured to perform specific functions Various embodiments may be implemented in a computer system that includes a graphical user interface and or an Internet browser To provide for interaction with a user some implementations may be implemented on a computer having a display device such as a CRT cathode ray tube or LCD liquid crystal display monitor for displaying information to the user a keyboard and a pointing device such as a mouse stylus ora trackball by which the user can provide input to the computer In various embodiments systems such as the data traffic modification device 105 may communicate using suitable communication methods equipment and techniques
34. n stored in non volatile memory In other embodiments one or more devices may be custom configured to perform specific functions A number of implementations have been described Nev ertheless it will be understood that various modifications may be made without departing from the spirit and scope For example advantageous results may be achieved if the steps of the disclosed techniques were performed in a different sequence if components in the disclosed systems were com bined in a different manner or if the components were replaced or supplemented by other components The func tions and processes including algorithms may be performed in hardware software or a combination thereof and some implementations may be performed on modules or hardware US 7 941 575 B2 17 not identical to those described Accordingly other imple mentations are within the scope of the following claims What is claimed is 1 A method of processing a waveform that comprises signals compliant with a version of a Serial Advanced Tech nology Attachment SATA protocol the method comprising receiving and sampling a bi directional data stream from a source device over a first SATA compliant data link selectively modifying the received data stream by moni toring the data stream and modifying at least one bit in the data stream in response to detecting a trigger condi tion wherein at least one bit to be modified is received in a buffer before receiving d
35. nd Apparatus which was filed by Roy A et al on Mar 3 2006 U S Patent Application Ser No 60 779 084 entitled Scenario View Method And Appara tus which was filed by Lee D et al on Mar 3 2006 U S Patent Application Ser No 60 779 180 entitled Processing Of Hold Command In Protocol Analyzer which was filed by Roy A et al on Mar 3 2006 U S Patent Application Ser No 60 779 085 entitled Communication Flow Recovery Method and Apparatus which was filed by Karpov D on Mar 3 2006 and U S provisional patent application 60 779 264 entitled Impairment and Monitoring Apparatus and Method by Roy A et al which was filed Mar 3 2006 This application also claims priority to U S Patent Application Ser No 60 892 093 entitled Data Traffic Modifier Method and Apparatus which was filed by Roy A et al on Feb 28 2007 The disclosures of each of these priority documents are incorporated herein by reference TECHNICAL FIELD Various embodiments relate to apparatus for modifying data traffic signals BACKGROUND Data rates continue to increase in digital systems commu nication systems computer systems and in other applica tions In such applications various devices communicate data using signals that may be encoded with information in the form of signal levels e g amplitude in certain intervals of time Proper decoding of signals for example may involve measuring
36. nding the received hold request signal to the source device comprises propagat ing the received hold request signal through the buffer 7 The method of claim 6 wherein the buffer comprises a first in first out buffer 8 The method of claim 1 wherein the signal from the target device to resume transmission of the data stream comprises a SATA compliant primitive to cancel a SATA compliant con tinuation primitive in effect 9 The method of claim 1 wherein the target device com prises a data storage device 10 The method of claim 9 wherein the data storage device comprises a rotating data storage medium 11 The method of claim 1 further comprising sampling the data stream with a protocol analyzer 12 The method of claim 1 wherein the step of selectively modifying the data stream comprises selectively modifying data in data traffic in more than one direction 13 A method of processing a waveform that comprises signals compliant with a version of a Serial Advanced Tech nology Attachment SATA protocol the method comprising receiving and sampling a bi directional data stream at an input module of a data traffic modification device the data traffic modification device being configured to buffer the received data stream in a buffer module to selectively modify data in the received data stream in 20 25 30 35 40 45 50 55 60 65 18 response to a trigger signal indicating the occurrence of a prede
37. odule 228 The scrambler module 228 may reduce the transmission of long repetitive data patterns that could contribute to electromagnetic interference Data leaving the scrambler module 228 is then passed to the third multiplexer 216 and the fourth multiplexer 218 Data passed to the third multiplexer 216 may pass the data to the fourth multiplexer 218 or vice versa or the data may be passed to a first hold handler 230 or a second hold handler 238 Data passed to the first hold handler 230 is sent to the initiator via an initiator port out 232 Data passed to the second hold handler 238 is sent to the target via a target port out 240 In operation the exemplary block diagram 200 illustrates a data traffic modification device configured to substantially reduce the propagation times that add delay to the acknowl edgment of a pause request from either an initiator or a target device Data propagating through the data modification path modules 214 220 228 236 may experience a delay caused by the previously described processing steps Some commu nication protocols such as the SATA specification for example specify that a transmitting device must within a specified response time such as 20 dwords double words or 32 bit values acknowledge a pause request signal by sus pending the transmission of valid data and by sending a hold acknowledgement signal to acknowledge the pause request The pause request may be to prompt the initiator to sus
38. oint out the location of an error within the incomplete scenario description 1050 In some embodiments the error location indicator 1040 may appear as a graphical indicator an animation a color code a text highlight a font alteration or a combination of these or other methods by which an erroneous line of a description may be indicated FIG 10c illustrates an exemplary erroneous scenario defi nition 1060 In this example the user has added three sequences to the erroneous scenario definition 1060 In this example the user has edited more than the allowed maximum of two sequences The editor GUI 1000 does not restrict the user from entering any invalid number of sequences to the erroneous scenario definition 1060 The editor GUI 1000 displays indicator based ona determination that the erroneous scenario definition 106C is invalid The status indicator 1030 and error location indicator 1040 provide the user with a graphical indication of the erroneous status of the erroneous scenario definition 1060 FIG 10d depicts an exemplary valid scenario definition 1070 The editor GUI 1000 determines the valid state of the valid scenario definition 1070 as each edit is made and status indicator 1030 is updated to reflect the valid status Examples of editing scenario definitions are described in further detail in U S provisional patent application 60 779 084 entitled Scenario View Method and Apparatus by Lee D et al which was filed Mar
39. or data traffic modification FIG 5 is a table that illustrates an exemplary communica tion session among a SATA initiator a data traffic modifica tion device and a SATA target when the SATA target requests a hold FIG 6 is a table that that illustrates an exemplary commu nication session among a SATA initiator a data traffic modi fication device and a SATA target when the SATA initiator requests a hold US 7 941 575 B2 3 FIG 7 is a block diagram depicting an exemplary method for processing a pause request from a SATA target coupled to a data traffic modification device FIG 8 is a block diagram depicting an exemplary process for handling a context using in a data traffic modification device FIGS 9a c illustrate two exemplary data substitution pro cesses being performed upon the data stream FIGS 10a d illustrate an exemplary graphical user inter face for viewing and editing data modification scenarios DETAILED DESCRIPTION FIG 1 illustrates a block diagram 100 of an exemplary configuration for using a data traffic modification device 105 The data traffic modification device 105 may be used to selectively modify some or all data traffic flowing between a SATA Serial Advanced Technology Attachment initiator 110 such as a computer with a SATA interface and a SATA target 115 such as a hard disk drive or drive array In some embodiments the selective modification of data may be per formed on data traffic in
40. orage Area Networks SANs http investor finisar com ReleaseDetail cfm pf yes amp ReleaseID 146677 printed Feb 7 2007 Oct 27 2004 2 pages Finisar Announces First Protocol Analyzer for Consumer Electron ics Storage Interface http investor finisar com releasedetail cfm ReleaseID 184656 Jan 18 2006 3 pages cited by examiner U S Patent May 10 2011 Sheet 1 of 10 US 7 941 575 B2 100 120 Protocol Analyzer En Initiator 110 Data Traffic Modification Device 105 FIG 1 U S Patent May 10 2011 Sheet 2 of 10 US 7 941 575 B2 200 ic Initiator Port In Target Port In 204 202 Primitive Inout Process Primitive Det Input Process NPULEROCES Detect 6160 06 Bypass FIFO 234 Hold Handier 230 Initiator Port Out 2 Hold Handler 238 Target Port Out 240 FIG 2 U S Patent May 10 2011 Sheet 3 of 10 US 7 941 575 B2 300 Data traffic modification SAS Device device 310 305 315 SAS Host FIG 3a 0 SAS Host SAS Data traffic modification SAS Device Expander device 312 325 305 318 FIG 3b 27 Data traffic modification SAS za SAS Host device Expander SAS Device 210 205 325 215 FIG 3c U S Patent May 10 2011 Sheet 4 of 10 US 7 941 575 B2 400 if 3 FIFO Underflow PRIM_IDLE PRIM_UNDF 402 412 alway
41. oth directions of a bidirectional communication link for example In FIG 2 data passing through the second multiplexer 212 flows through the dword buffer 236 In some embodiments the dword buffer 236 may be monitored by an event detect module 214 an event logic module 220 and or a sequencer module 22 which couples to a substitution module 224 Data from either or both of the input process modules 207 208 may be received as inputs to the event detection module 214 which may be configured e g programmed to identify selected primitives out of band OOB messages and the like The event detection module 214 may be configured for example to identify user Specified input conditions the occurrence of which may cause a processor to perform opera tions to selectively modify the data stream for example Signals from the event detection module 214 are received by the event logic module 220 which can be programmed by the user to provide a specified response to certain specified trig ger conditions e g primitives and data patterns detected in the event logic module 220 These responses may include actions that selectively modify data in the data stream drop data sound an audible beep stimulate a trigger port or per form a combination of these or other actions From the event logic module 220 control passes to a sequencer module 222 The sequencer module 222 may be implemented as a user programmable state machine The sequencer
42. paratus and associated systems and methods may relate to a data traffic modification system that may include a pro cessing module to handle SATA compliant data transfers in which a source device or a target device issues requests to pause and subsequently to resume the data transfer In various implementations a data traffic modification device may selectively modify data traffic upon the occurrence of a pre determined condition In one illustrative example if a target device for the data transfer issues a pause request e g to prevent a buffer overflow the data traffic modification device may generate a pause acknowledge signal to the target device within a response time specified by the protocol In another illustrative example if a source device for the data transfer issues a pause request the data traffic modification device may generate a pause acknowledge signal to the source device within the response time specified by the protocol Certain embodiments may provide one or more advan tages For example a data traffic modification system may smoothly and robustly handle high speed data transfers between a wide variety of source and target devices In vari ous implementations the data traffic modification device may overcome the delay associated with buffering the data trans fer by monitoring bidirectional data traffic for pause requests and responding rapidly by generating expected acknowledge signals within the response time expec
43. pend the data transfer to avoid for example a buffer overflow which may result in a loss of data or other problems The data paths for propagating the pause request through the data traffic modification device e g from the target port in 204 to the initiator port out 232 include a buffer or memory In the depicted example and depending on the states of the multi plexers 210 212 the data path through which a pause request would propagate includes either the bypass FIFO 234 or the dword FIFO 236 The FIFOs 234 236 may be for example buffers FIFO first in first out FILO first in last out circu lar linear parallel or combinations of these or other types of buffers In some embodiments the FIFOs 234 236 may be implemented using pointers to memory locations one or more data stores shift registers or a combination of these or other buffering techniques In operation of the example block diagram 200 the data traffic modification device may introduce a delay in the data stream In some examples such delay may substantially pre vent the device requesting a pause from receiving a pause acknowledgment signal within response time specification for the protocol being used Various embodiments may be adapted to meet a protocol s response time specification In an illustrative example a target device e g disk drive may issue a pause request to an initiator e g host or server that is transferring data to the target device
44. r performing traffic modification are described in further detail in U S provisional patent applica tion Ser No 60 892 093 entitled Data Traffic Modifier Method and Apparatus by Roy A et al which was filed Feb 28 2007 and the contents of which are incorporated herein by reference Although some examples describe apparatus and methods with reference to data traffic modifiers some features may apply to other implementations For example in one other embodiment a variant of the described graphical user inter face may be adapted for editing code for a protocol analyzer oscilloscope triggering mechanism logic analyzer and or other waveform processing systems 20 25 30 35 40 45 50 55 60 65 14 In some embodiments the data traffic modification device may receive updates or be monitored and or controlled from another e g remote computer with which the data traffic modification device can communicate over a communica tions link Such a communications link may include a soft ware control layer SCL running on the computer currently controlling the data traffic modification device In some embodiments the SCL may detect a failure to receive a com plete version of expected data The SCL may notify interested software layers that the request failed Before sending a new request for the desired data to be transmitted the SCL based on the knowledge of previously failed receive attempts may ch
45. response time specification for the communication protocol After the initiator issues the pause request the first primitive detect module 206 may detect the pause request and pass control to the first hold handler module 230 The first hold handler module 230 then generates a pause acknowledgement mes sage that is sent out the initiator port out 232 When the initiator breaks the pause state the substitution module 224 may generate signals to restore the context of the data stream that was in effect when the pause request was received Examples of restoring the context upon resuming the data transfer are described in further detail with reference to FIG 4 In some embodiments such as those that use a version of the SATA protocol the pause request may include for example a SATA HOLD primitive the acknowledge pause request may include a SATA HOLDA primitive and the continue primitive may include a SATA CONT primitive Some protocols may specify certain rules associated with such primitives For example some protocols may impose a response specification that a pause request for example be acknowledged within a certain time period or that only a limited quantity of data in the data stream be transferred after a pause request is issued Examples of processing pause primitives in a data traffic modification device are described in further detail in U S provisional patent application 60 779 180 entitled Processing Of Hold Command In Pro
46. ror detection value in the data traffic such that the updated error detection value corresponds to the selectively modified data with the introduced data error
47. s to step 832 where any data that may have been buffered from the target is sent to the host The process then returns to step 804 to receive additional primitives from the target FIGS 9a c illustrate a stream of data and two exemplary data substitution processes being performed upon the data stream FIG 9a depicts a series of ten dwords in a section of a data buffer 900 where each dword is numbered 0 9 In these examples the dword 0 arrived in the buffer first and each of the dwords arrived in sequence until dword 9 which arrived last In FIG 9a the data traffic modification device has been US 7 941 575 B2 11 triggered to sample data from dword 4 This trigger may be invoked by a predefined data pattern an offset from the start of a data frame after a timed offset an external trigger stimu lus or any other method that may be used to trigger a data traffic modification device or combinations thereof In this example the data traffic modification device has been con figured to sample the entire dword in cell 4 but in other embodiments the data traffic modification device may be configured to sample any number of bits within a data frame FIG 96 illustrates an example of a substitution process In this example the data traffic modification device has taken the data sampled from frame 4 and has used it to replace the data that was originally in frame 7 In some embodiments the data traffic modification device may perform this
48. sent to the host At step 816 data is received from the host If at step 818 the incoming data is a continued pause request primitive sequence then control passes to step 820 At step 820 the continued pause request primitive sequence is sent to the target At step 822 the data traffic modification device sets a holding state In some embodiments this may involve saving data setting a register bit or other types of computer memory so the data traffic modification device can recall that the device is in this state Control then passes to step 824 If at step 818 the incoming data is not a continued pause request primitive sequence then control passes to step 824 If at step 824 the data traffic modification device is not in a holding state then the process continues at step 826 other wise the process continues at step 828 At step 826 the data traffic modification device sends a acknowledge pause request primitive to the initiator The process then continues at step 832 where any data that may have been buffered from the target is sent to the host At step 828 the data traffic modification device recalls the state that was saved during step 808 and uses that state infor mation to re establish the continued state at step 830 For example if the saved state was a continued read in progress primitive state the data traffic modification device may send a continued read in progress primitive sequence to the host Control then passe
49. st primitive detect module 206 and a first input processing module 208 In some embodiments the primitive detect module 206 may be configured to react to or snoop for selected SATA primitives such as HOLD Data entering the block diagram 200 through the target port in 204 passes through a second input processing module 207 and a second primitive detect module 209 Data passing through the input processing module 208 is then passed to a first multiplexer 210 a second multiplexer 212 and an event detection module 214 The first multiplexer 210 and second multiplexer 212 as well as a third multiplexer 216 and a fourth multiplexer 218 are present to control the paths through which each direction of data traffic should propagate through the block diagram 200 In the depicted example both directions of data traffic are monitored but only one direction of data traffic can be selectively modified at any one time The direction of data traffic to be selectively modified is routed by the multiplexers to a dword FIFO 236 while the opposite direction of data traffic is routed through a bypass FIFO 234 In some other embodiments more than one direction lane or channel of data traffic may be modified at any one time For example multiplexers may be removed and or additional hardware and corresponding software examples of which are described below with reference to FIG 2 may be added to permit selective modification of data traffic in b
50. tate information during the data transfer receiving a Serial Advanced Technology Attachment SATA compliant HOLD primitive hold request from the source device to pause the data transfer US 7 941 575 B2 19 generating a SATA compliant HOLDA primitive hold acknowledgement in response to the received host request pausing the data transfer in response to the hold request receiving a signal from the source device to resume the data transfer generating signals to send to the source device the gener ated signals corresponding to the stored state informa tion in effect at the time of pausing the data transfer and resuming the data transfer after sending the generated sig nals 24 The method of claim 23 wherein the generated signals comprise at least two sequential SATA compliant primitive values corresponding to the stored state information 20 25 The method of claim 23 wherein receiving the request from the source device to pause the data transfer comprises monitoring the data traffic 26 The method of claim 25 wherein receiving the request from the source device to pause the data transfer further comprises detecting in the monitored data a SATA compliant signal to request a pause in the data stream 27 The method of claim 23 wherein selectively modifying the data traffic comprises introducing a data error 28 The method of claim 27 wherein selectively modifying the data traffic further comprises updating an er
51. ted by the device that issued the pause request In some particular embodiments a device capable of in line data traffic modification device may respond to pause request signals within a response time e g 20 double words as specified by various protocols e g SAS STP SATA SATA 2 0 and the like In one example before resuming a data transfer after being paused by for example a source device a data traffic modification device may advan tageously restore a context in effect when the data transfer was paused In another example after generating an acknowl edge signal in response to a pause request from a target device the data traffic modification device may advanta geously buffer data from the source device until the pause request propagates to the source device and the source device pauses the data transfer in response to the pause request The details of one or more embodiments are set forth in the accompanying drawings and the description below Other features objects and advantages will be apparent from the description and drawings and from the claims DESCRIPTION OF DRAWINGS FIG 1 illustrates a block diagram of an exemplary configu ration capable of modifying data traffic FIG 2 is a block diagram of an exemplary data traffic modification device FIGS 3a c are block diagrams depicting exemplary con figurations for using a data traffic modification device FIG 4 is a flow diagram of an exemplary state machine f
52. tocol Analyzer by Roy A et al which was filed Mar 3 2006 and the contents of which are incorporated herein by refer ence In some implementations the traffic modification device 105 may generate pause request acknowledgement signals to satisfy the response time specified by the applicable proto cols Exemplary implementations for processing pause requests in the configuration 100 are described with reference to FIGS 4 8 FIGS 3a c illustrate exemplary block diagrams depicting various configurations for using a data traffic modification device FIG 3a illustrates an exemplary block diagram 300 of an embodiment for the use of a data traffic modification device 305 In this embodiment the data traffic modification device 305 is placed between a SAS host 310 and a SAS device 315 In some embodiments the SAS device 315 may be replaced by a SATA device In some embodiments the SAS host 310 may be a SATA host if the configuration also includes a SATA device US 7 941 575 B2 7 FIG 36 illustrates and exemplary block diagram 320 of another embodiment for the use of the data traffic modifica tion device 305 In this embodiment the SATA host 310 is connected to a SAS expander 325 The SAS expander 325 is also connected to the data traffic modification device 305 and the data traffic modification device 305 is connected to the SAS device 315 FIG 3c illustrates an exemplary block diagram 330 of another implementation of the
53. upon the request of the user while saving a local copy of the scenario while deploy ing a scenario to a data traffic modification device or the like 20 25 30 35 40 45 50 55 60 65 12 Status indicator 1030 appears as a banner that is capable of displaying an indication of the validity status of the scenario In some embodiments this indication may be made using text a graphical indication animation color coding or other indications that may be used to convey a status or combina tions thereof In this example the status indicator 1030 dis plays an indication of the validity status of the scenario description 1020 FIG 106 illustrates the editor GUI 1000 and an exemplary adaptive text interface 1010 including an incomplete sce nario description 1050 In this example the user has added an event definition to the incomplete scenario description 1050 but the user has not added a corresponding action definition The editor GUI 1000 determines that the incomplete scenario definition 1050 is not a valid configuration for a data traffic modification device and the status indicator 1030 is updated to reflect this validity status In some embodiments the status indicator may provide an interactive functionality that allows the user to jump to the source of the invalid state within the incomplete scenario definition 1050 The editor GUI 1000 also includes an error location indicator 1040 which may be used to p
54. vice a data traffic modification device s initiator port shown in a column 520 a data traffic modification device s target port shown in a column 530 and a SATA target shown in a column 540 It should be noted that this table does not represent any particu lar time scale and is intended to be only a general depiction of one possible flow of communications In this example the initiator is sending data in cycles 1 3 It can also be seen that the target is sending a R_IP R_IP CONT sequence in cycles 1 3 to indicate that the target is receiving data At cycles 3 5 it can be seen that the R_IP sequence sent by the target has been relayed to the initiator port after some delay Likewise at cycle 7 the target sends a pause request as part of a HOLD HOLD CONT sequence and after a similar delay the HOLD HOLD CONT sequence is relayed at the initiator port Due to the normal delay required for the initiator to respond to a pause request in addition to the delay introduced by the data traffic modification device the initiator does not respond to the pause request until cycle 13 when it sends a hold acknowledgement primitive In some instances this delayed response may cause a buffer overrun if all the data packets were sent directly to the target In order to prevent a possible buffer overrun the data traffic modification device generates aseries of hold acknowledgement primitives starting at cycle 11 as depicted by the shaded cells an
55. y generate a GO6F 13 38 2006 01 pause acknowledge signal to the source device within the 52 US Claessen 710 29 710 33 710 54 710 72 response time specified by the protocol 58 Field of Classification Search None See application file for complete search history 28 Claims 10 Drawing Sheets oe 120 Protocol Analyzer nee 135 Initiator 125 Target 130 TL Data Traffic Modification Device 105 US 7 941 575 B2 Page 2 OTHER PUBLICATIONS SAS Infusion SATA Infusion FAQ LeCroy Protocol Solutions Group 2006 3 pages SAS Infusion and SATA Infusion Error Injector and Traffic Modi fier LeCroy Protocol Solutions Group Believed to have been pub licly available as of Mar 29 2005 6 pages Infusion 1 20 Release Notes Updated Aug 21 2006 LeCroy Protocol Solutions Group Aug 21 2006 5 pages Product Bulletin IF 001 SAS SATA Infusion Announcement LeCroy Protocol Solutions Group Feb 28 2005 2 pages LeCroy Introduces Error Injection System For Serial Attached SCSI And Serial ATA LeCroy Press Release Mar 1 2005 2 pages Finisar Adds SAS and SATA Protocols to Its Industry Leading Xgig R Analyzer 3 0 http investor finisar com ReleaseDetail cfm pf yes amp ReleaseID 1 86233 printed Feb 7 2007 Feb 1 2006 2 pages Finisar Announces Next Generation Analysis Solutions for St
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