96-277r1 - Proposed Change in QErr for SPC-2

Jim Mcgrath jmcgrath at QNTM.COM
Wed Feb 19 19:39:53 PST 1997

* From the SCSI Reflector (scsi at symbios.com), posted by:
* jmcgrath at qntm.com (Jim Mcgrath)


You wrote:

Unless someone can refute Ralph's rationale for all SCSI systems (not just 
demonstrate that it is possible to live with QErr=01 in selected 
environments), our only consistent alternatives are to prohibit 
multi-initiator simple queuing systems, or to accept Ralph's proposal.  Of 
the two, I think Ralph's proposal is the simplest.

And here I disagree.  I think it is perfectly fine for the standard to state
that the behaviour of a simple queing drive in a multiple initiator environment
is vendor unique.  There are a lot of cases in the standard today where using
things in a certain combination is not covered explicitly by the standard.
Vendor unique is not bad - it is just vendor unique.

This position is the compromise I am willing to accept.  But the whole idea of
basic queueing was to eliminate complicated error recovery scenerios in the
firmware as developed and tested for a drive that is intended to be shipped
into single initiator systems.  We have not had multi-initiator support in
our low end SCSI drives for years - and the market has accepted that very 
well.  This point was discussed extensively in the committee when we made
the original basic queuing decision, and agreed to overwhelmingly.


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