Queue tag size in Packetized SCSI?

[gop at us.ibm.com]

* From the T10 Reflector (t10 at t10.org), posted by:
* gop at us.ibm.com
*
Guy,
The correct answer is both. The TAG field being referred to in section
16.4.1 is the 8-bit value contained in the task attribute messages. These
messages are used when packetized SCSI is not being used. They occur during
the initial connection as the Q in the I_T_L_Q nexus.
When packetized SCSI is being used the TAG field in the SPI L_Q information
unit is defined as a 16-bit field and it contains the Q for the I_T_L_Q
nexus.
The cross-reference in SPI-3 you referred to is there because the
referenced section gives more information about tags and how they are used
but the size of the TAG is specified by the field size.

Bye for now,
George Penokie

Dept Z9V  114-2 N212
E-Mail:    gop at us.ibm.com
Internal:  553-5208
External: 507-253-5208   FAX: 507-253-2880



"Kendall, Guy" <Guy.Kendall at lsil.com> on 03/07/2000 02:59:16 PM

To:   t10 at t10.org
cc:
Subject:  Queue tag size in Packetized SCSI?




* From the T10 Reflector (t10 at t10.org), posted by:
* "Kendall, Guy" <Guy.Kendall at lsil.com>
*
In SPI-3, revision 13.a in section 14.3.2, the TAG field is shown at 16
bits
in the SPI L_Q. The text describing this field says "The tag is an 16 bit
unsigned integer..." Then it refers you to section 16.4.1 for more details
on tags. In section 16.4.1, it says "The TAG field is an 8-bit unsigned
integer..." and goes on to say "For each logical unit on each target, each
application client has up to 256 tags to assign to tasks".

So are tags 8 or 16-bit for packetized SCSI (Information Units enabled) ?

Thanks,
Guy
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