Draft minutes of Parallel SCSI WG - Aug 24-25, 2000

John Lohmeyer lohmeyer at t10.org
Mon Aug 28 12:31:38 PDT 2000


* From the T10 Reflector (t10 at t10.org), posted by:
* John Lohmeyer <lohmeyer at t10.org>
*
A PDF version of these minutes is available at:

   ftp://ftp.t10.org/t10/document.00/00-304r0.pdf

Accredited Standards Committee*
National Committee for Information Technology Standards (NCITS)

                                                     Doc. No.: T10/00-304r0
                                                         Date: August 28, 2000
                                                     Reply to: John Lohmeyer

To:      T10 Membership
From:    Ralph Weber & John Lohmeyer
Subject: Parallel SCSI Working Group Meeting -- August 24-25, 2000
          Denver, CO


Agenda

1.  Opening Remarks
2.  Approval of Agenda
3.  Attendance and Membership
4.  SPI-4 Physical Topics
4.1   Training Patterns
4.1.1     Data Out Phase (00-272) [Leshay]
4.1.2     Getting Training Started in SPI-4 (00-324) [Penokie]
4.2   Timings
4.2.1     Proposal for revision of the timing tables and definitions in SPI-4
(00-323) [Milligan]
4.3   Other SPI-4 Physical Topics
4.3.1     LVD Driver Balance for Ultra320 SCSI (00-319) [Uber]
4.3.2     PIP & SSM Report (00-301 & 00-302) [Ham]
4.3.3     Requirements for Measuring Receive Signals in SPI-4 and beyond
(00-149) [Ham]
4.3.4     Specifying signals at receiver using receiver equalization (00-223)
[Uber]
4.3.5     Cable Attenuation (00-235r0) [Uber]
4.3.6     Cable measurements and Calculated Signal Loss (00-276) [Manildi]
4.3.7     Calculated Signal Losses (00-227 and 00-246) [Aloisi]
4.3.8     SPI-4 - Assumptions for the Receiver and Driver levels (00-239)
[Aloisi]
4.3.9     Vn for OR-Tied Signals (00-320) [Moore]
4.3.10      Periodic structures on SCSI buses (00-327) [Barnes]
4.3.11      The zero offset problem for receiver equalization (00-201)
[Bridgewater]
4.3.12      Losses on LVD Buses (00-331) [Uber]
4.4   Protocol
4.4.1     Assertion handshaking protocol for Ultra320 SCSI (00-271 and 00-311)
[Evans and Leshay]
4.4.2     Results of letter ballot on making PPR Pace_On bit reserved (00-024,
00-292) [Lohmeyer and Penokie]
4.4.3     Conflict in Data IU Exception Handling (reflector messages)
[Srinivasan]
4.4.4     Packetized streaming clarification (00-326) [Galloway]
4.4.5     Vendor unique IU type (00-325) [Galloway]
4.4.6     Disabling Precompensation (00-321) [Moore]
4.4.7     QAS without IU in SPI-4 (00-252) [Elliott]
4.4.8     Bidirectional data transfers in SPI-4 (00-314) [Elliott]
4.4.9     Buffer Credits (99-324r0) [Moore]
4.5   Receiver Issues
4.5.1     Receiver Response Requirements (00-332) [Ham]
5.  SPI-4 review [Penokie]
5.1   SPI-4 Clarifications (00-322) [Moore]
6.  Expanders and Domain Validation Topics
6.1   Report on the SCSI Domain Validation Meeting (00-303) [Lohmeyer]
7.  New Business
7.1   Standard Is A Functional Description (00-333) [Milligan]
8.  Meeting Schedule
9.  Adjournment




Results of Meeting

1.  Opening Remarks

John Lohmeyer, the T10 Chair, called the meeting to order at 1:00 p.m.,
Thursday, August 24, 2000.  He thanked LSI Logic for hosting the meeting.

As is customary, the people attending introduced themselves and a copy of the
attendance list was circulated.


2.  Approval of Agenda

The draft agenda was approved with the no changes.

The following items were added/revised during the course of the meeting:

4.3.12      Losses on LVD Buses (00-331) [Uber]
7.1   Standard Is A Functional Description (00-333) [Milligan]


3.  Attendance and Membership

Attendance at working group meetings does not count toward minimum attendance
requirements for T10 membership.  Working group meetings are open to any
person or organization directly and materially affected by T10's scope of
work.  The following people attended the meeting:

          Name          S        Organization         Electronic Mail Address
---------------------- -- ------------------------- -------------------------
Mr. Ron Roberts        A  Adaptec, Inc.             Ron_Roberts at adaptec.com
Mr. Mike F. Allen      A  AMP / Tyco Electronics    mallen at tycoelectronics.
                                                     com
Mr. Michael D.         V  AMP / Tyco Electronics    mdgallow at tycoelectronics.
Galloway                                            com
Mr. Vince Bastiani     V  Bass Technology           bass.tech at gte.net
Mr. Bill Galloway      P  BREA Technologies, Inc.   billg at breatech.com
Dr. William Ham        A  Compaq Computer Corp.     bill_ham at ix.netcom.com
Mr. Ralph O. Weber     A  ENDL Texas                roweber at acm.org
Mr. George O. Penokie  P  IBM Corp.                 gop at us.ibm.com
Mr. John Lohmeyer      P  LSI Logic Corp.           lohmeyer at t10.org
Mr. Larry Barnes       V  LSI Logic Corp.           larry.barnes at lsil.com
Mr. Michael Bratvold   V  LSI Logic Corp.           mike.bratvold at lsil.com
Mr. Brian Day          V  LSI Logic Corp.           brian.day at lsil.com
Mr. Frank Gasparik     V  LSI Logic Corp.           frank.gasparik at lsil.com
Mr. Jeffrey J. Gauvin  V  LSI Logic Corp.           jeff.gauvin at lsil.com
Mr. Alan Littlewood    V  LSI Logic Corp.           alanl at lsil.com
Mr. David Noeldner     V  LSI Logic Corp.           dave.noeldner at lsil.com
Mr. Sriram Srinivasan  V  LSI Logic Corp.           sriram.srinivasan at lsil.
                                                     com
Mr. Richard Moore      A# QLogic Corp.              r_moore at qlc.com
Mr. Richard L.         V  QLogic Corp.              r_romaniec at qlc.com
Romaniec
Mr. Tim Hsia           V  QLogic Corp.              t_hsia at qlc.com
Mr. Henry Kuo          V  QLogic Corp.              h_kuo at qlc.com
Mr. Mark Evans         P  Quantum Corp.             mark.evans at quantum.com
Mr. Bruce Leshay       V  Quantum Corp.             bleshay at tdh.qntm.com
Mr. Richard Uber       V  Quantum Corp.             duber at tdh.qntm.com
Mr. Gene Milligan      P  Seagate Technology        Gene_Milligan at notes.
                                                     seagate.com
Mr. Mayank R. Patel    V  Seagate Technology        mayank_r_patel at notes.
                                                     seagate.com
Mr. Paul D. Aloisi     P  Texas Instruments         Paul_Aloisi at ti.com
Mr. Mike Kosco         V  Texas Instruments         mike at mvbuilders.com

28 People Present

Status Key:  P    -  Principal
              A,A# -  Alternate
              O    -  Observer
              L    -  Liaison
              V    -  Visitor


4.  SPI-4 Physical Topics

4.1 Training Patterns

4.1.1 Data Out Phase (00-272) [Leshay]

Bruce Leshay ask that discussion of this topic be deferred to the next
meeting.

4.1.2 Getting Training Started in SPI-4 (00-324) [Penokie]

George Penokie presented a compilation of all the various proposals and
discussions of training requirements in SPI-4 (00-324r0).  Bill Galloway
suggested that the ordering of activities be compared to some kind of absolute
time T0 (the beginning of training).  The goal was to provide some way of
referencing when something happens to replace phrases such as
"simultaneously", "after" and "immediately after".  George agreed to include
something based on Bill's suggestion along with other corrections in the next
revision of the proposal.

George walked the group through clause 10.8.4.3.3 in SPI-4 revision 1.  The
group agreed on changes that clarify when a DT DATA IN phase without training
starts.  George agreed to make several other changes in the draft SPI-4 before
distributing revision 1.

4.2 Timings

4.2.1 Proposal for revision of the timing tables and definitions in SPI-4
(00-323) [Milligan]

Gene Milligan presented proposed revisions to the timing definitions in SPI-4
(00-323r1).  The group discussed the method by which the timings were
calculated.  Gene noted several clarifications in the wording of definitions
in the proposal.

Upon completing the review of the proposal, Gene asked if the group wished to
document the timings using method 1 or method 2.  (See 00-323r1 for a
definition of method 1 and method 2.)  Bill Galloway noted that method 2 will
be impossible to test in the lab using an oscilloscope.  Gene noted that
method 1 is going to have unexpected values in the setup and hold times.
George commented that documenting method 1 will be harder than documenting
method 2, however, George supported use of method 1 because of the need for
people to use direct content from the standard to evaluate products under
development something that probably would be impossible if the standard
adopted method 2.  In the absence of any objections, the group agreed to use
method 1.

The group discussed whether to remove the Fast-80 (Reference) column from the
Fast-160 Timing Budget Template table.  In the absence of any objections, the
group agreed to remove the column.

4.3 Other SPI-4 Physical Topics

4.3.1 LVD Driver Balance for Ultra320 SCSI (00-319) [Uber]

Richard Uber raised questions (00-319r0) about the practicality of the driver
asymmetry equations agreed at the last meeting (00-276r0).  While the group
shared Richard's concerns about the impossibility of building drivers that
meet the 276 requirements, several of those present wished to carefully review
the proposed changes before agreeing to them.  It was also noted that making
the changes proposed in 00-319 would adversely affect the timing budget.

Richard notified the group he intended to request approval of 00-319r0 for
inclusion in SPI-4 at the September meetings.

4.3.2 PIP & SSM Report (00-301 & 00-302) [Ham]

Bill Ham asked that this item be deleted from future agendas.

4.3.3 Requirements for Measuring Receive Signals in SPI-4 and beyond (00-149)
[Ham]

Bill Ham asked that discussion of this topic be deferred to the next meeting.

4.3.4 Specifying signals at receiver using receiver equalization (00-223)
[Uber]

Richard Uber asked that discussion of this topic be deferred to the next
meeting.

4.3.5 Cable Attenuation (00-235r0) [Uber]

Richard Uber asked that discussion of this topic be deferred to the next
meeting.

4.3.6 Cable measurements and Calculated Signal Loss (00-276) [Manildi]

Bruce Manildi was unable to attend and discussion of this topic was deferred.

4.3.7 Calculated Signal Losses (00-227 and 00-246) [Aloisi]

Paul showed the 00-227r7 spreadsheet noting that the bottom line is not
acceptable to some.  Paul proposed that the strong driver level be required to
be from 500 mV to 800 mV and the fallback be 50% and showed the effects of
this change in 00-227r8.  Bruce Leshay questioned the use of such a large
fallback range.

Paul concluded by noting that the r8 changes focus on getting more margin
across all the silicon that is coming out.  Brian Day noted that the ability
of the weak signal to go below 300 mV and other aspects of the r8 need careful
consideration.

Paul reviewed the specific proposed SPI-4 changes in 00-246r4 (matching the
00-227r8 spreadsheet).  The group discussed details of the proposed changes
and Paul noted areas needing correction.

Gene suggested that the timing diagram is overloaded with level information
and that the level information can be placed in the mask diagrams.

The "System Level Requirements" table and the notes for the table required
substantial editing.

Paul stated that the proposals will be revised and cleaned up for the
September meeting.  He asked for feedback from all involved to help get the
proposals in a condition that works for everybody.  George urged everybody to
review 00-246r5 carefully so that a vote can be taken at September meeting.

4.3.8 SPI-4 - Assumptions for the Receiver and Driver levels (00-239) [Aloisi]

Paul Aloisi reviewed the written assumptions document (00-239r3) matching the
00-227r7 spreadsheet as well as the 00-239r4/00-227r8 pair covering the new
ideas brought forward in the last couple of days.  Concerns were raised about
how SPI-4 can go about specifying the receiver filtering behavior.

4.3.9 Vn for OR-Tied Signals (00-320) [Moore]

Richard Moore presented a proposal describing problems with SPI-4 requirements
on device leakage current and terminator impedance and bias properties.

Gene Milligan asked if this should be made into an erratum to SPI-3.  Richard
stated that the issue was raised as a letter ballot comment on SPI-3 that was
rejected.  Therefore, Gene suggested that SPI-4 be written in such as way as
to indicate that SPI-3 was incorrect (or at least incomplete).

The group recommend that the change in Vn for OR-Tied Signals be accepted with
a note indicating that SPI-3 failed to account for leakage current.  Paul
Aloisi agreed to reflect the group's agreement in his document, eliminating
the need for further processing on 00-320.

4.3.10  Periodic structures on SCSI buses (00-327) [Barnes]

Larry Barnes presented a method for modeling the behavior of a SCSI bus that
might help get better margins for SCSI bus and backplane structures.  He noted
that much work remains to be done, however, he felt that the tools presented
may be helpful in the future.

4.3.11  The zero offset problem for receiver equalization (00-201)
[Bridgewater]

Vince Bastiani asked that discussion of this topic be deferred to the next
meeting.

4.3.12  Losses on LVD Buses (00-331) [Uber]

Richard Uber presented a discussion of loss problems in LVD busses (00-331)
with the goal that several new concepts be taken into account in future
analyses of DC noise margins.

4.4 Protocol

4.4.1 Assertion handshaking protocol for Ultra320 SCSI (00-271 and 00-311)
[Evans and Leshay]

Bruce Leshay proposed that the acknowledgment signal (REQ or ACK) run at the
clock rate but with an additional requirement that only the leading edge be
counted (or that the trailing edge may be ignored) and that each leading edge
represent 32 bits of data.  Bruce noted that the change affects the meaning of
the REQ/ACK Offset, doubling the number of bits represented by a given REQ/ACK
Offset value.

Mark Evans moved that 00-311r1 be accepted for inclusion in the next revision
of SPI-4.  Bill Galloway seconded the motion.  Ron Roberts requested the
ability request reconsideration of the proposal at the September meeting in
the event that his engineers have issues and George agreed to give him that
option.  The motion passed on a vote of 5:0:3.

4.4.2 Results of letter ballot on making PPR Pace_On bit reserved (00-024,
00-292) [Lohmeyer and Penokie]

John Lohmeyer announced the results of the PPR Pace_On letter ballot, results
in 00-024.  The ballot passed on a vote of 34:0:2:3.  On letter ballot comment
(from IBM) requested incorporating 00-292r1 in place of r0.  Gene Milligan
objected to incorporating r1 without a review of the changes in r1.  In the
review, some instances where "paced" was changed to "DT data" were questioned.
Other wording problems were raised and George agreed to make changes in
00-292r2.

George Penokie moved that the working group recommend resolution of the letter
ballot comments in 00-024 by recommending inclusion of 00-292r2 (r1 as
revised) for inclusion in SPI-4.  Bill Galloway seconded the motion.  The
motion passed by a vote of 8:0:1.

4.4.3 Conflict in Data IU Exception Handling (reflector messages) [Srinivasan]

George Penokie explained the history of IU error retry handling including the
decision that IU error handling will not include performing retries.  Sriram
Srinivasan explained that SPI-4 allows retries and should continue to do so.
George noted that the text referenced by Sriram was left in SPI-4 in error and
proposed that it be removed.

Sriram brought up two other issues that George Penokie agreed to review after
the meeting and report on via the T10 Reflector.  Further discussion of the
issues was deferred to the next meeting.

4.4.4 Packetized streaming clarification (00-326) [Galloway]

Bill Galloway proposed adding a one-sentence recommendation for streaming
implementations.  The group requested changes and Bill agreed to revise the
proposal.  Bill Galloway moved that 00-326r1 (r0 as revised) be accepted for
inclusion in SPI-4.  Brian Day seconded the motion.  In the absence of any
objections, the motion passed unanimously.

4.4.5 Vendor unique IU type (00-325) [Galloway]

Bill Galloway proposed that 16 IU type codes be changed from reserved to
vendor unique.  Bill Galloway moved that 00-325r0 be accepted for inclusion in
SPI-4.  Gene Milligan seconded the motion.  The group discussed how to support
the new type codes when the content of the IU is unknown without agreeing on
any specific changes.  The motion passed on a vote of 7:2:1.

4.4.6 Disabling Precompensation (00-321) [Moore]

Richard Moore proposed that the sense of the precompensation bit in the PPR
message be reversed to have a bit value of 1 mean "disable precompensation".
Reversing the sense of the bit was not acceptable, but other wording
clarifications found some acceptance.  The group requested changes in the
proposal (including keeping the sense of the precompensation bit unchanged)
and Richard agreed to provide a revised proposal.  Richard Moore moved that
00-321r1 (r0 as revised) be accepted for inclusion in SPI-4.  Mark Evans
seconded the motion.  The motion passed on a vote of 10:0:1.

4.4.7 QAS without IU in SPI-4 (00-252) [Elliott]

Rob Elliott (via email) asked that discussion of this topic be deferred to the
next meeting.

4.4.8 Bidirectional data transfers in SPI-4 (00-314) [Elliott]

Rob Elliott (via email) asked that discussion of this topic be deferred to the
next meeting.

4.4.9 Buffer Credits (99-324r0) [Moore]

Richard Moore proposed changes to the acknowledgment mechanism similar to the
proposal presented in item 4.4.1.  On a suggestion from Gene Milligan, Richard
agreed to withdraw the proposal as it has been overtaken by events.  Richard
also agreed to return with the proposal near the beginning of SPI-5
development if the general direction of that work might benefit from
reconsideration of the proposal.

4.5 Receiver Issues

4.5.1 Receiver Response Requirements (00-332) [Ham]

Bill Ham announced that he received no official responses from Seagate, LSI
Logic, Adaptec, and Quantum.  Therefore, he wrote his own proposal, 00-332
with some unofficial assistance from Frank Gasparik for which Bill expressed
appreciation.  Bill informed the group that the document will be presented at
the September meeting and proposed for incorporation in SPI-4 at that time.


5.  SPI-4 review [Penokie]

5.1 SPI-4 Clarifications (00-322) [Moore]

Richard Moore presented two proposed clarifications for SPI-4.  The group
asked for the opportunity to review the proposal with their engineers.
Richard agreed to bring the proposal back to the September meeting.  He noted
that he may remove the figure from the September revision of the proposal.


6.  Expanders and Domain Validation Topics

6.1 Report on the SCSI Domain Validation Meeting (00-303) [Lohmeyer]

John Lohmeyer reported on the activities of the Domain Validation working
group (minutes in 00-303).


7.  New Business

7.1 Standard Is A Functional Description (00-333) [Milligan]

Gene Milligan presented a very preliminary statement intended for the Scope
clause of all SCSI standards.  The intent of the statement is that any
implementation that conforms to the interoperability requirements of the
standard is okay.  The group asked that the proposal be discussed at the
September CAP meeting.

8.  Meeting Schedule

The next meeting of the Parallel SCSI Working Group will be Tuesday September
12, 2000 commencing at 9:00 a.m. in Huntington Beach, CA.

The group agreed to add an agenda item titled "ATN timing for Paced Transfers"
to the September meeting agenda and Bill Galloway agreed to draft a proposal
for discussion under that topic.

9.  Adjournment

The meeting was adjourned at 12:20 p.m. on Friday August 25, 2000.


--
John Lohmeyer                  Email: lohmeyer at t10.org
LSI Logic Corp.                Voice: +1-719-533-7560
4420 ArrowsWest Dr.              Fax: +1-719-533-7183
Colo Spgs, CO 80907

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