98-145r0 - Discovering If This Is SES Port A or Port B

Gene_Milligan at notes.seagate.com Gene_Milligan at notes.seagate.com
Wed Apr 22 16:57:14 PDT 1998

* From the T10 (formerly SCSI) Reflector (t10 at symbios.com), posted by:
* Gene_Milligan at notes.seagate.com
<<For years, SCSI provided an acceptable means for the application client
to learn the identity of the port being used for communications, but that
capability was expunged from SCSI recently based on the idea that a
standard covering only two-port devices must be insufficient.  The problem
was further complicated by lack of an agreed mechanism for
identifying obsolete definitions, which resulted in the port identify-
ing mechanism being labeled vendor-specific when it should have been
labeled obsolete.>>

     Well this is not quite correct as I recall. I think the definition was
not in any version of the standard forwarded by T10 - strictly unchecked
memory. Consequently it would not have been eligible for the Obsolete
definition. The only equitable choice for those that had implemented it on
good faith under the circumstances you mentioned was to label the controls
vender specific.

     Very nice research on the background, but it seems to me T10 can not
in good conscious <<It is proposed that SPC-2 reclaim the "obsolete" Port
bit by extending the MultiP field to encompass both bits 4 and 5 as
follows:>> since the bit was not "obsolete" it was vender specific. The
only equitable way to pursue the proposal would be to look for reserved
bits. An alternative might be to define it as optionally vender specific or
optionally to your proposal. But that sounds like chaos.


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