HiSupport bit description in Inquiry

George Penokie gop at us.ibm.com
Fri Jul 31 06:20:19 PDT 1998


* From the T10 (formerly SCSI) Reflector (t10 at symbios.com), posted by:
* George Penokie <gop at us.ibm.com>
*

Bob,
The HiSuport bit is not part of SCC. I believe it was invented when the
hierarchical addressing model was incorporated into SAM-2. I like your idea of
having zero mean supports the standard definitions and 1 be the something else
condition.

Bye for now,
George Penokie

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




Bob.Snively at Ebay.Sun.COM on 07/27/98 05:39:49 PM
Please respond to Bob.Snively at Ebay.Sun.COM
To: George Penokie/Rochester/IBM at ibmus, roweber at acm.org
cc: bob.snively at Sun.COM
Subject: RE: HiSupport bit description in Inquiry


Ralph,

It might however be interesting to rename the bit to indicate
that the bit shall be 0 for hierarchical and compliant flat spaces
and 1 for "other" spaces.  Unfortunately, this is probably the wrong
polairy in the present SCC document.

Bob


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X-Sender: ralphoweber at pop.site1.csi.com
Date: Fri, 24 Jul 1998 21:18:06 -0500
To: T10 at Symbios.COM
Subject: RE: HiSupport bit description in Inquiry
Mime-Version: 1.0

* From the T10 (formerly SCSI) Reflector (t10 at symbios.com), posted by:
* "Ralph O. Weber" <roweber at acm.org>
*
Gerry,

Oh boy did you scare the **** out of me.  I thought the
HiSupport bit was a problem and drafted a reflector message
on the subject.  Then, I deleted it for reasons I'll
describe in a moment.  You had me thinking I'd lost
control of my e-mail tools again.  (It's not April
Fools day, right!)

If you look carefully at clause 4.8 in SAM-2 r8, you will
see that there's an edge condition where HiSupport will
have to be zero.  I believe it's a really gross edge
condition, but you can be the judge.  If a device has
a flat LUN space and more than 256 LUNs there is no
standard-defined way to represent all those LUNs in
the Peripheral Device addressing method, or any other
valid hierarchical LUN scheme.

I judged that it would be okay to allow a non-hierarchical
address in these cases, ran the text by George and Bob and
got them to agree (at least until the September meeting).
So, for the next couple of months HiSupport is still needed
to do it's old job.  But, if further changes are made in
September, then maybe we should remember to decide about
HiSupport's fate too.

Thanks.

Ralph...



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