[T10] Operation of TAS bit related to Unit Attention

George Penokie george.penokie at avagotech.com
Tue Jan 26 12:56:49 PST 2016


Bill,

It is that way because the zero case was the legacy behavior in SCSI before
there was a TAS bit.

Bye for now,
George Penokie

Avago Technologies
Attn: George Penokie
4109 Manor View Dr NW
Rochester , MN 55901

952-921-2495
george.penokie at avagotech.com

On Tue, Jan 26, 2016 at 2:08 PM, Bill Martin-SSI <
bill.martin at ssi.samsung.com> wrote:

> The biggest confusion here was the apparent opposite meaning of the bit,
> but now it is clear that the functionality of the bit was designed in that
> when set to one tasks are completed with TASK ABORTED status and there is
> no UA. When set to zero tasks are aborted with no response to the
> application client and a UA issued.
>
>
>
> Thanks,
>
>
>
> Bill Martin
>
> Vice Chair SNIA Technical Council
>
> Vice Chair INCITS T10
>
> SSD I/O Standards
>
> Samsung Semiconductor, Inc.
>
> Cell (408) 499-1839
>
>
>
>
>
>
>
> *From:* Black, David [mailto:david.black at emc.com]
> *Sent:* Tuesday, January 26, 2016 10:25 AM
> *To:* Bill Martin-SSI; George.Penokie at avagotech.com; Ralph Weber (
> roweber at ieee.org) (roweber at ieee.org)
> *Cc:* T10 Reflector
> *Subject:* RE: Operation of TAS bit related to Unit Attention
>
>
>
> I’m neither Ralph nor George, but I don’ t see a serious conflict:
>
> - The SAM-5 text is about creating a unit attention condition that is
> reported on a **subsequent** command (if it is reported, see SAM-5 on UA
> queuing behavior).
>
> - The SPC-4 text is about how to terminate the **current** command.
>
>
>
> It might be nice if each chunk of text acknowledged the existence of the
> other, but that would be editorial.  What have I missed?
>
>
>
> Thanks, --David
>
>
>
> *From:* t10-bounces at t10.org [mailto:t10-bounces at t10.org
> <t10-bounces at t10.org>] *On Behalf Of *Bill Martin-SSI
> *Sent:* Tuesday, January 26, 2016 11:11 AM
> *To:* George.Penokie at avagotech.com; Ralph Weber (roweber at ieee.org) (
> roweber at ieee.org)
> *Cc:* T10 Reflector; Stefanus (Fnu) Stefanus-SSI
> *Subject:* [T10] Operation of TAS bit related to Unit Attention
>
>
>
> Ralph & George:
>
>
>
> There is a conflict between SAM-5 and SPC-4 on the meaning of the TAS bit.
>
>
>
> SAM-5r21 states:
>
> If the TAS bit is set to zero in the Control mode page (see SPC-4), then
> the device server creates this unit attention condition for each I_T nexus
> that had command(s) aborted other than the I_T nexus that delivered the
> command. If the TAS bit is set to one in the Control mode page (see SPC-4),
> then the device server does not create this unit attention condition.
>
>
>
> SPC-4r08 states:
>
> A task aborted status (TAS) bit set to zero specifies that aborted
> commands shall be terminated by the device server without any response to
> the application client. A TAS bit set to one specifies that commands
> aborted by the actions of an I_T nexus other than the I_T nexus on which
> the command was received shall be completed with TASK ABORTED status (see
> SAM-5).
>
>
>
> Which was the intended meaning of this bit?
>
>
>
> Thanks,
>
>
>
> Bill Martin
>
> Vice Chair SNIA Technical Council
>
> Vice Chair INCITS T10
>
> SSD I/O Standards
>
> Samsung Semiconductor, Inc.
>
> Cell (408) 499-1839
>
>
>
>
>
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