Draft Minutes of T10 Plenary Meeting #20 - 3/13/97

John Lohmeyer John.Lohmeyer at symbios.com
Mon Mar 24 09:23:45 PST 1997


* From the SCSI Reflector (scsi at symbios.com), posted by:
* John Lohmeyer <John.Lohmeyer at Symbios.com>
*
At 05:50 PM 3/21/97 -0800, Jim Mcgrath wrote:
>     
>     I am a bit confused on this upcoming meeting - since Ultra 3 could
>     very well have protocol changes as well as speed changes, is this
>     the scope of the meeting?  Or is it only to focus on the narrow
>     question of Fast 80?  (It is important since different people
>     would come depending on the scope of the meeting).

Jim,

The April 18th meeting in San Jose was authorized as a SPI-2 Working Group
meeting.  Obviously, a major consideration of this meeting is whether or
not we should recommend to T10 that SPI-2 be 'unstabilized' in the area of
LVD drivers, receivers, and terminators.  

At the March 10th SPI-2 working group meeting, Adaptec presented data that
they believe implies we may eventually want to be using symmetrical drivers
with non-biased terminators and dual receivers (one biased and one not).
SPI-2 currently specifies asymmetrical drivers with biased terminators and
non-biased receivers.

A key technical point that I think the working group needs to address is at
what speed will the symmetrical drivers be needed (if at all)?

If the case for eventually needing symmetrical drivers is persuasive, then
a marketing recommendation is needed on the timing; should we recommend
changes to SPI-2 or wait for a future version of SPI?  This question is
much more difficult because many elements must be considered.  For example,
what factors are most important to the parallel SCSI market: higher speed,
reduced overhead, or increased connectivity?  You presented interesting
(and controversial) data on this point at the last SCSI Working Group meeting.

I will be preparing a draft agenda and distributing it to the reflector
soon.  I think it is beyond the scope of the meeting to invent Fast-80 or
'Ultra3' (whatever Ultra3 means).  However, we will have to have some idea
of where we are going to judge the merit of Adaptec's proposal.

Since the meeting is only one day, I want to devote as much time as is
necessary to the question of symmetrical vs. asymmetrical.  We owe the
industry resolution of this question ASAP.  If any time remains, I want to
cover other SPI-2 issues, particularly those than can benefit from the
flock of physical experts I am expecting.  

Exploring protocol enhancements is probably not going to receive much time
(but is extremely interesting to me).  We have agreed to put this topic on
Tuesday afternoon of the SCSI Working Group.

John

--
John Lohmeyer                 E-Mail: john.lohmeyer at symbios.com
Symbios Logic Inc.             Voice: 719-533-7560
4420 ArrowsWest Dr.              Fax: 719-533-7036
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