Issue with READ/WRITE 10 & 12 byte commands

Devon Worrell worrell at dt.wdc.com
Tue Jul 15 12:10:10 PDT 1997


* From the T10 (formerly SCSI) Reflector (t10 at symbios.com), posted by:
* Devon Worrell <worrell at dt.wdc.com>
*
Hi,

There is now a large issue that was (Is still) discussed at the MMC-2
meeting. The Diskboys (Mass Storage Profile) is using only the 10 byte
commands, but MtFuji is using only the 12 byte commands.

The Read Feature needs to use ONLY ONE of these. The mtfuji-1 SFF8090
specifies 12 bytes, but it is my believe that all the drives currently
support 10 byte read/write commands. Is this true? If this is true
then can we change MtFuji-2 to use only 10 byte commands?

This is REALLY IMPORTANT and needs to be resolved in the next month!!!

Currently it is apparent that 10 byte commands are used. It is not
so clear that 12s are used today. DOES ANYONE USE 12 BYTE READ
and WRITE commands?

MMC is currently thinking that the 12 byte commands be removed or that
both the 10 and 12 SHALL be supported. They are currently thinking that
the 10 byte commands are mandatory and that the 12 would, IF SUPPORTED,
be defined in a feature such as AV Streaming.

Folks that are in the Host Domain, please respond on your position. Those
that are in the Drive Domain, please indicate if using only 10 will be
a problem.

Let me know,

Devon,

    _/_/_/_/    _/_/_/_/    _/      _/ | Devon B. Worrell <worrell at dt.wdc.com>
   _/      _/  _/      _/  _/      _/  | Senior Staff Engineer
  _/      _/  _/_/_/_/    _/  _/  _/   | Western Digital Corporation
 _/      _/  _/       _/ _/_/_/_/_/    | 8105 Irvine Center Dr, Irvine CA 92618
_/_/_/_/    _/_/_/_/_/  _/      _/     | Host Interface & Technology Staging
                                       | Ph: (714) 932-7042 Fax: (714) 932-7796

"Every truth passes through three stages before it is recognized.
 In the first it is ridiculed, in the second it is opposed, in the
 third it is regarded as self-evident!"

"Not speaking in an official capacity for my employer"

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