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IDEMA – JAPAN Discussion summary of AV commands for ATA-7 Consumer HDD Committee

IDEMA – JAPAN Discussion summary of AV commands for ATA-7 Consumer HDD Committee. 26th/June/2002. 22th/August/2002. 23th/October2002. IDEMA-JAPAN consumer HDD committee appreciates T-13 activities.

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IDEMA – JAPAN Discussion summary of AV commands for ATA-7 Consumer HDD Committee

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  1. IDEMA – JAPANDiscussion summary of AV commands for ATA-7 Consumer HDD Committee 26th/June/2002 22th/August/2002 23th/October2002

  2. IDEMA-JAPAN consumer HDD committee appreciates T-13 activities. Set box manufacturing companies of the committee member really need to standardize AV command. To reject confusion and to get compatibility of alternate or future HDD. IDEMA-JAPAN consumer HDD committee agrees basic concept of current ATA-7 AV commands. However IDEMA-JAPAN consumer HDD committee requests some modification to avoid misunderstanding as well as to use them effectively. IDEMA-JAPAN understand Command completion within the Time Limit should always have priority. These comments to follow are discussed by IDEMA-JAPAN consumer HDD committee's Sub WG members; Toshiba, Hitachi, JVC, Matsushita, Sanyo, SONY, Pioneer Maxtor Japan, Seagate Japan, Western Digital Japan, Japan IBM Fujitsu, Intention of IDEMA-JAPAN

  3. 8/22 Outline of IDEMA-JAPAN’s 8/20-22 proposal 8/22 8/22

  4. CONFIGURE STREAM

  5. CONFIGURE STREAM T13 DraftPage 61 5.8 CONFIGURE STREAM IDEMA Japan Requests Add annotation; 5.8.8 Description If CONFIGURE STREAM was not issued, refer 4.17.1 Streaming commands 2nd paragraph and 5.37.4 Features register previous. 4.17.1 Streaming commands 2nd paragraph Page 40 If the host does not use a CONFIGURE STREAM command, the device shall use the time specified in each streaming command. The streaming commands may access any user LBA on a device. These commands may be interspersed with non-streaming commands, but there may be an impact on performance due to the unknown time required to complete the non-streaming commands. 5.37.4 Features register previous. Page 195 If the value is zero, the device shall use the Default Command Completion Time Limit supplied with a previous Configure Stream command for this Stream ID. If the Default Command Completion Time Limit is zero, or no previous Configure Stream command was defined for this Stream ID, the result is vendor specific. Reason for IDEMA Japan Requests To eliminate ambiguity. Ex) If stream command was used without setting CONFIGURE STREAM, READ/WRITE Stream properties was preference and work well.

  6. CONFIGURE STREAM – Register Bit 7 : A/R T13 DraftPage 61 A/R specifies a request to add a new stream if set to one. If cleared to zero, a request to remove a previous configured stream is specified. IDEMA Japan Requests Agree Reason for IDEMA Japan Requests None

  7. CONFIGURE STREAM – Register Bit 6 : R/W T13 DraftPage 61 R/W specifies a read stream if cleared to zero and a write stream if set to one. IDEMA Japan Requests It is necessary to clarify whether an individual stream ID can be configured as read and write streams concurrently or not. Ex) Case 1.If yes: Configure ID1 Read with CCTL1-> Configure ID1 Write with CCTL2 => ID1 Read with CCTL1 and ID1 Write with CCTL2 Case 2.If No: Configure ID1 Read with CCTL1-> Configure ID1 Write with CCTL2 => ID1 Write with CCTL2 Only Case 1 is requested. Reason for IDEMA Japan Requests Understanding bellow ○ ×

  8. 8/22 CONFIGURE STREAM – Register Bit 6 : R/W IDEMA Japan Requests ○ ○ IDEMA-JAPAN wants to use that one content is allowed to assign 1 stream ID. The reason is 1. HDD wants to recognize the difference between following Read after Write with same stream and simultaneously Read and Write with a different stream. 2.Host think easy operation will be allowed regarding handle of stream ID, because the rule which is not flexible makes a stream command hard to use

  9. CONFIGURE STREAM – Register Bit (2:0) : Stream ID T13 DraftPage 61 R/W specifies a read stream if cleared to zero and a write stream if set to one. IDEMA Japan Requests Agree Reason for IDEMA Japan Requests None

  10. CONFIGURE STREAM – Register Bit (7:0) : Timer Limit T13 DraftPage 61 The default command completion time limit. The value is calculated as follows: (Default command completion time limit) = ((content of the Features register) * (IDENTIFY DEVICE words (99:98))) m seconds IDEMA Japan Requests If improper CCT value was issued, additional error report need to be define. Reason for IDEMA Japan Requests If command completion time limit is too small to complete a command, all data will be returned as error. That makes contradiction.

  11. 8/22 The processing way for the Improper Command Completion Time Case 1 - Reject the improper value as compared with a guideline Case 2 - Report as an error after command execution ex. If this type error occurs in Read Stream DMA/PIO mode or Write Stream DMA/PIO mode, we understand the error status is SE=0 ERR=1 Now IDEMA-JAPAN feel case 2 is better,because it is difficult to decide a proper guideline 8/22 IDEMA-JAPAN propose new error bit “CCTO”(Command Completion Time Limit OUT). CCTO bit is defined at bit “0” in Error register.

  12. READ STREAM DMA/PIO – Register Bit 7 : AU T13 Draft Page61 Sector Count Current - The size of an Allocation Unit in sectors (bits 7:0). Sector Count Previous - The size of an Allocation Unit in sectors (bits 15:8). IDEMA Japan Requests Agree Reason for IDEMA Japan Requests None

  13. READ STREAM DMA/PIO

  14. READ STREAM DMA/PIO – Register Bit 7: URG T13 DraftPage195/Page199 URG specifies an urgent transfer request. The Urgent bit specifies that the command should be completed in the minimum possible time by the device and shall be completed within the specified Command Completion Time Limit. IDEMA Japan Requests/Comment Definition of “minimum possible time” is necessary. Is there any specific reason for URG bit? Reason for IDEMA Japan Requests/Comment Implication of “minimum possible time” is not clearly defined. IDEMA Japan CE members may not use URG bit. Does it mean “without error recovery”? If so, “with hidden error recovery” or “without hidden error recovery”? If not, what is the difference of URG and RC?

  15. READ STREAM DMA/PIO – Register Bit 6: RC T13 Draft Page195/Page199 RC specifies Read Continuous mode enabled. If the RC bit is set, the device shall transfer the requested amount of data to the host within the Command Completion Time Limit even if an error occurs. The device may transfer unspecified data in an attempt to meet the Command Completion Time Limit. If the Command Completion Time Limit expires, the device shall terminate the data transfer. If the RC bit is clear, the device shall stop on an error. • IDEMA Japan Requests/Comment • RC specifies Read Continuous mode enabled. If the RC bit is set, the device shall transfer the requested amount of data to the host within the Command Completion Time Limit with error recovery even if an error occurs. The device may transfer unspecified data in an attempt to meet the Command Completion Time Limit. If the Command Completion Time Limit expires, the device shall terminate the data transfer. If the RC bit is clear, the device shall transfer the correct data to the host within the Command Completion Time Limit with error recovery. the device shall stop on an error. If the Command Completion Time Limit expires, the device shall terminate the data transfer. • 2. Command completion within the Time Limit should always have priority. Description of ABRT should include Command Completion Time Out Error case and new bit definition for Command Completion Time Out Error should be assigned. Reason for IDEMA Japan Requests/Comment The device shall always transfer correct data to the host as much as possible.

  16. CCT CCT CCT Explain READ STREAM DMA/PIO Normal case (RC=1 or RC=0) requested amount of data no error transfer correct data RC=1 : transfer the requested amount of data SE=1,ERR=0 requested amount of data Device status become ready at the beginning of next CCT period Error Try error recovery until CCT X If error recovery don’t success, device may transfer unspecified data transfer correct data unspecified data = include incorrect data RC=0 : transfer correct data SE=0,ERR=1 requested amount of data Device status become ready at the beginning of next CCT period Error Try error recovery until CCT X If error recovery success,device transfer correct data. If error recovery don’t success,device don’t transfer the data. transfer correct data

  17. Our definition of error recovery Error recovery Attempt to transfer the requested amount of correct data exactly,or receive the requested amount of all data as much as possible within the Command Completion Time Limit expires

  18. READ STREAM DMA/PIO – Register Bit 5: NS 8/22 T13 Draft Page195/Page199 (Not Sequential) may be set to one if the next read stream command with the same Stream ID may not be sequential in LBA space. IDEMA Japan Requests/Comment NS may not be needed. efficient by command pre-fech and 2 stream R/W case Is Command pre-fech standard?　→　Now standard IDEMA-JAPAN agree using NS bit. 8/22 Reason for IDEMA Japan Requests/Comment Implication and effect of NS is not clearly defined.

  19. READ STREAM DMA/PIO – Register Bit 4: HSE T13 Draft Page195/Page199 (Handle Streaming Error) specifies that this command starts at the LBA of the last reported error for this stream, so the device may attempt to continue its corresponding error recovery sequence where it left off earlier. IDEMA Japan Requests/Comment Effective. Reason for IDEMA Japan Requests/Comment Effective for IT data with READ STREAM DMA/PIO.

  20. READ STREAM DMA/PIO – Register Bit (2:1): Stream ID T13 Draft Page195/Page199 Stream ID specifies the stream to be read. IDEMA Japan Requests/Comment If a Stream ID that is different from the pre-defined Stream ID by CONFIGURE STREAM command is specified, the device shall ignore the specified Stream ID. This sentence need to re-consider in idema-japan Clarify idema-japan request Reason for IDEMA Japan Requests/Comment If a specified Stream ID is different from the pre-defined Stream ID defined by previous CONFIGURE STREAM command, the device shall ignore the newly specified Stream ID.

  21. CCT CCT 8/22 What is “HSE” operation RC=0 : transfer correct data SE=0,ERR=1 requested amount of data Device status become ready at the beginning of next CCT period Error Try error recovery until CCT X If error recovery succeed,device transfer correct data. If error recovery don’t succeed,device don’t transfer the data. transfer correct data HSE=1 CCT CCT Read Stream DMA/PIO with HSE=1 or 0 Read Stream DMA/PIO with HSE=1 X X Only Error Recovery again ? →suppose Vendor Specific Transfer Correct data Error Recovery using Even if stream ID is not defined, We suppose read command error recovery process Is performed from the beginning of latest error position, because of read stream command after error occurred has include the error LBA number. And a host manages streams essentially Error Log Entry Stream ID Starting Error LBA address

  22. WRITE STREAM DMA/PIO

  23. WRITE STREAM DMA/PIO – Register Bit 7: URG T13 Draft Page321/Page 325 URG specifies an urgent transfer request. The Urgent bit specifies that the command should be completed in the minimum possible time by the device and within the specified Command Completion Time Limit. IDEMA Japan Requests/Comment Definition of “minimum possible time” is necessary. Is there any specific reason for URG bit? Reason for IDEMA Japan Requests/Comment Implication of “minimum possible time” is not clearly defined. IDEMA Japan CE members may not use URG bit. Does it mean “without error recovery”? If so, “with hidden error recovery” or “without hidden error recovery”? If not, what is the difference of URG and WC?

  24. WRITE STREAM DMA/PIO – Register Bit 6: WC T13 Draft Page321/Page 325 WC specifies that the Write Continuous mode enabled. If the WC bit is set to one and an error occurs, the device shall transfer all of the data for the command without stopping to post an error. If the WC bit is cleared to zero and an error occurs, the device may stop transferring data. • IDEMA Japan Requests/Comment • WC specifies Write Continuous mode enabled. If the WC bit is set, the device shall receive the requested amount of data from the host within the Command Completion Time Limit even if an error occurs. The device shall receive requested amount of data even if the received data may be abandoned.And the status of device shall become ready after receiving the requested amount of data. When an error occurs, SE=1, ERR=0. If the device can not receive the data for impossible CCT value is issued,error status is SE=0,ERR=1.→SE=1,ERR=0 & Error log check • If the WC bit is clear, the device may stop to receive the data from the host if an error occurs. When an error occurs,SE=0,ERR=1. • Command completion within the Time Limit should always have priority. Description of ABRT should include Command Completion Time Out Error case and new bit definition for Command Completion Time Out Error should be assigned. Reason for IDEMA Japan Requests/Comment

  25. CCT CCT CCT Explain WRITE STREAM DMA/PIO Normal case (WC=1 or WC=0) requested amount of data no error Device may stop to receive the data. receive data WC=1 : receive the requested amount of data SE=1,ERR=0 requested amount of data How about treat Crc error ? Device status become ready at the beginning of next CCT period Error Try error recovery until CCT X receive a part of data If error recovery don’t success, device receive data continuously. Even if the received data may be abandoned In worst case WC=0 : receive data SE=0,ERR=1 requested amount of data Device status become ready at the beginning of next CCT period Error Try error recovery until CCT X If error recovery success,device receive the data. If error recovery don’t success,device may stop to receive the data. receive a part of data

  26. WRITE STREAM DMA/PIO – Register Bit 5: F T13 Draft Page321/Page 325 F specifies that all data for the specified stream shall be flushed to the media before command complete is reported when set to one IDEMA Japan Requests/Comment effective Reason for IDEMA Japan Requests/Comment

  27. WRITE STREAM DMA/PIO – Register Bit 4: HSE T13 Draft Page321/Page 325 HSE (Handle Streaming Error) specifies that this command starts at the LBA of the last reported error for this stream, so the device may attempt to continue its corresponding error recovery sequence where it left off earlier IDEMA Japan Requests/Comment Definition of “HSE” operation is necessary. Reason for IDEMA Japan Requests/Comment Basically “HSE” may not needed. Generally the device can not understand “write error” without an action of “read after write“. And when the host will transfer its stream data to the device again, the host usually will transfer the requested amount of data. Is there any specific reason for HSE bit?

  28. CCT 8/22 WRITE STREAM DMA/PIO – Register Bit 4: HSE WC=0 : receive data SE=0,ERR=1 requested amount of data Device status become ready at the beginning of next CCT period Error Try error recovery until CCT X If error recovery success,device receive the data. If error recovery don’t success,device may stop to receive the data. receive a part of data HSE=1 CCT CCT Write Stream DMA/PIO with HSE=1 or 0 Write Stream DMA/PIO with HSE=1 X X Only Error Recovery again ? →suppose Vendor Specific Transfer Correct data Error Recovery using Case-1 using HSE bit Drive may perform reallocation process Case-2 not using HSE bit Host system may use another area to dislikes the situation of error sectors only separated →IDEMA-JAPAN thinks Case-2 is better Error Log Entry Stream ID Starting Error LBA address

  29. WRITE STREAM DMA/PIO – Register Bit 3-1: Stream ID T13 Draft Page321/Page 325 Stream ID specifies the stream to being written. IDEMA Japan Requests/Comment If a Stream ID that is different from the pre-defined Stream ID by CONFIGURE STREAM command is specified, the device shall ignore the specified Stream ID. Reason for IDEMA Japan Requests/Comment Undefined Stream ID shall be ignored. 今回の提案はDraftに直ぐには反映しない。 McLeanさんのまとめた資料を送るので、日本で継続検討して欲しい 最終的にはDraftに反映する　　

  30. 6.69 WRITE STREAM DMA 6.69.4 Inputs If WC is set to one and an error occurs in the transfer or writing of the data, the device shall continue to transfer and write all of the requested data・・　 and write means All of the requested data will be written until CCTL was expired The devide has finished to write all data to diskinclude Reallocation (Problem : If reallocation area will be spend)  Therefore IDEMA-JAPAN thinks - Usuallyhost system dislikes the situation of error sectors only separated - “and write”will be delete - Processing include reallocation is Device vendor specific - “ transfer “ is remain

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