Late SPC-4 Letter Ballot comment request
gerry.houlder at seagate.com
Thu Dec 13 06:46:34 PST 2012
Formatted message: <a href="http://www.t10.org/cgi-bin/ac.pl?t=r&f=r1212130_f.htm">HTML-formatted message</a>
It is unclear how your new requirements should be inserted into the quoted
text. Have you prepared a proposal for this?
On Wed, Dec 12, 2012 at 5:48 PM, Kevin D Butt <kdbutt at us.ibm.com> wrote:
> IBM would like to request a late letter ballot comment against SPC-4 to
> consider an additional way to indicate when an Error history snapshot is
> lost. The following text highlights what is currently stated about error
> history snapshots, their persistent requirements, how to report a loss of a
> snapshot or error history I_T nexus, and that there may be vendor specific
> methods to retrieve error history.
> It is well known that Unit Attentions are often swallowed by application
> client stacks before the application has a chance to see them. For this
> reason, having a Check Condition instead of a UA is preferable, at least in
> some environments. Also, error history may be retrieved by vendor specific
> methods or other READ BUFFER command sequences. The size of the error
> history buffers in some implementations could be such that these other
> methods would have to share these error history buffers. Or other vendor
> specific requirements may force a release of the error history snapshot.
> Currently, this would be a violation of the standard.
> We would like to allow vendor specific events in addition to the timer to
> cause a release of the snapshot. We would also like to report this through
> a Check Condition, ILLEGAL REQUEST, ERROR HISTORY SNAPSHOT RELEASED on a
> subsequent READ BUFFER with mode 1Ch.
> 5.5.2 Retrieving error history with the READ BUFFER command
> The device server shall not replace or release the error history snapshot
> while the error history I_T nexus is established.
> The device server shall implement a vendor specific timer for error
> history snapshot retrieval. If the vendor specific timer expires, then:
> a) the device server shall:
> A) clear the error history I_T nexus; and
> B) establish a unit attention condition for the error history I_T
> nexus with the additional sense code set to ERROR HISTORY I_T NEXUS
> b) the device server shall:
> A) clear the error history I_T nexus;
> B) release the error history snapshot; and
> C) establish a unit attention condition for the error history I_T
> nexus with the additional sense code set to ERROR HISTORY SNAPSHOT
> Error history may also be retrieved by vendor specific methods or other
> READ BUFFER command sequences that are outside the scope of this standard.
> Kevin D. Butt
> SCSI & Fibre Channel Architect, Tape Firmware
> Data Protection & Retention
> MS 6TYA, 9000 S. Rita Rd., Tucson, AZ 85744
> Tel: 520-799-5280
> Fax: 520-799-2723 (T/L:321)
> Email address: kdbutt at us.ibm.com
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