Re 3+: Re[2]: Draft Minutes of T10 Plenary Meeting #20 - 3/13/97

Skip Jones sk_jones at
Wed Mar 26 14:40:46 PST 1997

* From the SCSI Reflector (scsi at, posted by:
* Skip Jones <sk_jones at>

Actually, according to some that know this transmission line/pad design
field far better than I do, not only is it possible but preferrable that
we DO try to keep as seperate as possible issues of transmission line
effects on pad designs, asymmetry VS symmetry, and the notion of
encoding.  Most importantly, lets not over-tangle these issues with
concepts such as increased addressability and protocol overhead
reduction.  Different disciplines are expert in each and different
problems are addressed by each.

I especially want to discourage any bygone conclusions that signal
encoding is necessary or even desirable.  There may be far more
palletable ways of accomplishing the same results that should be
exhausted before we jump off the deap end and make SCSI into something
so complex, expensive, and incompatible with anything that we ensure a
quick insertion of bullet in head.

At a minimum, we should explore adding an option ASAP in SPI-2 which
provides an Ultra2 backward compatible method of providing the strict
electrical transmission line signaling requirements which allow Fast-100
speeds.  I did not say we should necessarily spec FAST-80 right now.  I
said only spec the minimum required for further growth of the interface
so that we can get on with building product but not drive ourselves into
a dead-end, awaiting some ultimate SPI-3 solves-everything-for-everybody

I believe that there are some options and alternatives available to us
that could close this issue in relative short order, and may even allow
everyone to have and eat cake simultaneously.  I think the best way to
resolve is to get the the real experts in this area to sit down together
and work the details WITHOUT guys like me distracting their efforts!  We
have terrific talent here at my company as does your company, Adaptec,
Symbios, Quantum, and Bill Ham - guys that live and breath this stuff
and guys that design pads for a living and have lots of success under
their belts.  These are the guys that need to sit down and resolve this
possible corner we've worked our way into.  

I don't know if its symmetrical, asymmetrical, step-down voltages after
the appropriate sample, or putting parallel fibre optic converters on
the darn bus, but I do know that if these guys can walk out of a meeting
together nodding in agreement, we'll probably have the best and most
expeditious answer for the industry, our markets, and most importantly,
our customers.  

I hope that us veterans of the committee can round-up our experts in
this field for a real working session on April 18th and that us vets
keep those that cannot technically contribute either busy at some trade
show, customer site, or their mouth mostly shut so that these guys can
work towards an expeditious conclusion that serves us all.  The more we
try to wrap too many issues/features into this electrical transmission
line issue and the more passion and politics we bring into the arena,
the less likely that we'll reach any meaningful conclusions in a time
span that matters and the less likely we'll have good SCSI with us for
as long as we should.

I'll do my part!  I may show up, but I'm encouraging a true engineering
meeting so I hope to sit in the far back of the room and catch-up on my
expense reports!

See ya there! (Maybe)

Skip Jones
Director, Planning and Technology

QLogic Corporation
3545 Harbor Blvd.
Costa Mesa,  CA  92626
(714) 668-5058 Phone
(714) 668-5008 Fax
sk_jones at

>From: 	Gene Milligan[SMTP:Gene_Milligan at]
>Sent: 	Monday, March 24, 1997 5:10 AM
>To: 	John Lohmeyer
>Cc: 	Jim Mcgrath; scsi
>Subject: 	Re 3+: Re[2]: Draft Minutes of T10 Plenary Meeting #20 -
>* From the SCSI Reflector (scsi at, posted by:
>* Gene Milligan <Gene_Milligan at>
>John wrote among other things:
><I will be preparing a draft agenda and distributing it to the
>soon.  I think it is beyond the scope of the meeting to invent Fast-80
>'Ultra3' (whatever Ultra3 means).  However, we will have to have some
>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
>cover other SPI-2 issues, particularly those than can benefit from the
>flock of physical experts I am expecting.  >
> I do not see how a proposal to change from asymmetrical drivers to
>drivers due to limitations for Fast-80 can be decided without
>specifying the 
>Fast-80 parameters (including coding).
>* For SCSI Reflector information, send a message with
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