Amendment of Get Performance Write Speed (Type 3)

keiji_katata at keiji_katata at
Tue Feb 20 02:59:44 PST 2001

* From the T10 Reflector (t10 at, posted by:
* keiji_katata at

  Hello all,

  I would like to propose the amendment of Get Performance command. I have
  2 items. Please open  Mt.Fuji5 Ver. 1.20 page 281.

  1:lost Performance header of Write Speed (type 3)

  13.6.4 Write Speed (Type field = 03h) on page 281, the Performance header
  is lost. In my original proposal, the result data format is same as Table
  184 - GET PERFORMANCE Result Data. The header structure is same as Table
  185 - Performance Header. So I would like to propose to add following
  sentence just before Table 195 - Write Speed Descriptor as follows;

  The result data and Header shall be formatted as listed in Table 184 on
  page 276 and Table 185 on page 276.

  2:Data Length filed definition of Performance header

  In the case of Read TOC command on page 403, the description of Data
  Length is
  "The TOC Data Length specifies the length in bytes of the following TOC
  data. The TOC Data Length value does not include the TOC Data Length
  field itself. This value is not modified when the allocation length is
  insufficient to return all of the TOC data available."
  So host can set Allocation Length field in CDB to necessary length and
  can determine number of information blocks.

  In the case of Get Performance command, The description on page 276 is
  "The Performance Data Length field shall indicate the amount of result
  data that follows the Performance Data Length field."
  Host may or may not be able to determine how many descriptors are
  available now. I got question about this issue. I think some
  clarification or modification should be need.

  First of all, I would like to ask the actual implementation of member's
  products. Currently PIONEER's product reports actual data length
  transferred. So this is different with Read TOC command manner. Would you
  check actual implementation before next meeting? This is very big issue
  must be solved in the next meeting.

  I also got 3 opinions about modification.
  a) define byte 6-7 for number of current available descriptors field.

  b) add extra rule to Maximum Number of Descriptors field of CDB. If
  Maximum Number of Descriptors field is set to 0, device reports Header
  only and Data Length field in Header shall indicate length of all
  descriptor data available.

  c) same definition with Read TOC command. Device shall report length of
  all descriptor data available and shall not modify the data length to
  adjust to insufficient Maximum Number of Descriptors of Command
  Descriptor Block.

  I think the same definition with Read TOC command (c) is smart.

  Anyway, we need to check the current implementation of product ASAP.

  Best regards,
  Keiji Katata


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