Draft Minutes of SPI-2 Working Group - 3/10/97

John Lohmeyer John.Lohmeyer at symbios.com
Tue Mar 18 21:24:43 PST 1997


* From the SCSI Reflector (scsi at symbios.com), posted by:
* John Lohmeyer <John.Lohmeyer at Symbios.com>
*
These minutes are available in PDF format from:

 ftp://ftp.symbios.com/pub/standards/io/x3t10/document.97/97-137r0.pdf

Minutes of SPI-2 Working Group                                 T10/97-137r0

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

                                                    Doc. No.: T10/97-137r0
                                                        Date: March 18, 1997
                                                     Project: 1142-D
                                                   Ref. Doc.:
                                                    Reply to: John Lohmeyer

To:         Membership of T10

From:       Ralph Weber, Secretary T10
            Larry Lamers, Vice-chair T10
            John Lohmeyer, Chair T10

Subject:    Minutes of SPI-2 Working Group
            March 10, 1997 -- San Diego, CA


                                  Agenda

1. Opening Remarks

2. Approval of Agenda

3. Attendance and Membership

4. Universal backplane [Wallace/Barnes]

5. LVD case 4 hot plugging [Barnes]

6. Changing driver modes when hot plugging (96-270r1)  [Penokie]

7. Single-ended termination (96-245r2) [Wallace]

8. Proposed clarification to Fig. 24 [Ham]

9. Issues with LVD [Harris]

10. Considerations for Ultra3 (97-146r0) [Harris/Bastiani/Gintz]

11. Integration Issues [Lamers]

12. Bus Set Delay Reduction (97-116) [Ham]

13. Hot-Plugging Data (97-144r0) [Ham]

14. REQ/ACK Glitch Filters [Ham]

15. Meeting Schedule

16. Adjournment




                              Results of Meeting

1.    Opening Remarks

John Lohmeyer, the T10 Chair, called the meeting to order at 9:00 a.m., Monday
March 10, 1997.  He thanked Skip Jones of QLogic for hosting and arranging the
meeting.

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

2.    Approval of Agenda

The agenda was approved with the following additions:
      13. Hot-Plugging Data [Ham]
      14. REQ/ACK Glitch Filters [Ham]

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. Norm Harris        P  Adaptec, Inc.             nharris at eng.adaptec.com
Mr. Tak Asami          A# Adaptec, Inc.             asami at itc.adaptec.com
Mr. Lawrence J. Lamers A  Adaptec, Inc.             ljlamers at aol.com
Mr. Wally Bridgewater  V  Adaptec, Inc.             wally at eng.adaptec.com
Mr. Tom Scheinder      V  Adaptec, Inc.
Mr. Bill Gintz         V  Adaptec, Inc.
Mr. Vincent Bastiani   V  Adaptec, Inc.             bastiani at corp.adaptec.com
Mr. Paul Wang          V  Adaptec, Inc.
Mr. Charles Brill      P  AMP, Inc.                 cebrill at amp.com
Ms. Bonnie Rose        V  Amphenol                  brose at cosmosgroup.com
Mr. Ron Roberts        A  Apple Computer            rkroberts at aol.com
Mr. Bob Gannon         O  C&M Corp.                 bobg848740 at aol.com
Mr. Siegfried Schmalz  A  Dallas Semiconductor      schmalz at dalsemi.com
Mr. Greg McSorley      P  Data General / Clariion   greg_mcsorley at dgc.ceo.dg.
                                                    com
Dr. William Ham        A# Digital Equipment Corp.   ham at subsys.enet.dec.com
Mr. George Penokie     P  IBM Corp.                 gop at rchvmp3.vnet.ibm.com
Mr. Louis Grantham     A  Linfinity Micro           lgdatcom at ix.netcom.com
Mr. Mark Granahan      V  Linfinity Micro           mgranahan at aol.com
Mr. Alan Littlewood    O  LSI Logic                 alanl at lsil.com
Mr. Wayne E. Werner    O  Lucent Technologies       wewerner at lucent.com
Mr. Daniel (Dan) F.    V  Mr. Brian N. Davis        daniel_smith at notes.seagate
Smith                                               .com
Mr. Skip Jones         P  QLogic Corp.              sk_jones at qlc.com
Mr. Ting Li Chan       A  QLogic Corp.              t_chan at qlc.com
Mr. Gene Milligan      P  Seagate Technology        Gene_Milligan at notes.
                                                    seagate.com
Mr. Gerald Houlder     A  Seagate Technology        Gerry_Houlder at notes.
                                                    seagate.com
Mr. Dave Guss          P  Silicon Systems, Inc.     dave.guss at tus.ssi1.com
Mr. Vit Novak          A  Sun Microsystems, Inc.    vit.novak at sun.com
Mr. John Lohmeyer      P  Symbios Logic Inc.        john.lohmeyer at symbios.com
Mr. Ralph O. Weber     A  Symbios Logic Inc.        roweber at acm.org
Mr. Brian McKean       A  SyQuest Technology, Inc.  brian.mckean at syquest.com
Mr. Pete Tobias        P  Tandem Computers          tobias_pete at tandem.com
Mr. Jack Shiao         O  Tandem Computers          jack at loc3.tandem.com
Mr. Dave Wehrman       O  UNISYS                    dwehrman at unisys.com
Mr. Paul D. Aloisi     P  Unitrode Corporation      aloisi at unitrode.com
Mr. Gregory Kapraun    V  Western Digital Corp.     kapraun at wdroc.wdc.com
Mr. Doug Piper         P  Woven Electronics         doug.piper at internetmci.com

36 People Present

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

4.    Universal backplane [Wallace/Barnes]

Yes, it can be done.  Larry Barnes was reported to have a tool that allows the
calculation of the geometry for the backplane given the desired impedance.
Larry plans to provide at least one set of numbers as an example; but he does
not plan to provide the tool for developing the numbers.

5.    LVD case 4 hot plugging [Barnes]

John Lohmeyer said that last time he had been asked about whether Larry Barnes
would be able to finish his simulation work on LVD case 4 hot plugging and
whether Larry's input data were available.  Unfortunately, Larry no longer has
access to the simulation software, which is quite expensive.  Also Larry
declined to disclose the input data because it includes proprietary
information about the Symbios Logic LVD pad.  John suggested that this item be
dropped from future agendas.

See also item 13.

6.    Changing driver modes when hot plugging (96-270r1)  [Penokie]

George presented the proposal that requires reporting of transceiver mode
changes to and from LVD.  Gerry Houlder suggested that the ASC/ASCQ
definitions be placed under the 29h ASC, as new ASCQs.  George agreed with the
suggestion and undertook to revise the proposal.

7.    Single-ended termination (96-245r2) [Wallace]

Louis Grantham presented revised proposal for the SPI-2 Termination I/V curve.
He displayed the impedance characteristics for several different cables, in
support of the proposal.  After a brief discussion, the group agreed
to continue discussing the proposal on the SCSI Reflector and to bring a
proposal based on the results of the discussion to the next meeting.

8.    Proposed clarification to Fig. 24 [Ham]

Bill Ham said that his data suggest that figure 24 should not be changed.
Bill requested that this issue be dropped from the agenda.  John Lohmeyer
expressed concern that an inconsistency exists if the figure is not changed.
John and Bill discussed changes that should and should not be made to the
figure.  The group agreed to review the figure again at the next meeting,
after everybody has a chance to review the current proposed figure with their
engineers.

9.    Issues with LVD [Harris]

Norm Harris began his presentation with a review of the development of LVD
SCSI.  The conclusion of Norm's presentation was that there are no
demonstrable problems with LVD SCSI at 40 mega-transfers per second.  However,
the same signaling technology cannot be run at faster transfer speeds, say 80
mega-transfers per second, without some changes to signaling technology,
device count, or maximum cable length.

10.   Considerations for Ultra3 (97-146r0) [Harris/Bastiani/Gintz]

Vincent Bastiani described a test setup used evaluate the signal integrity of
the current LVD SCSI definition.  Bill Ham noted the "first pulse detection"
issue described by Vincent is exactly the "inter-symbol interference" issue
that he has described during past meetings.  Bill Gintz gave some analysis of
the causes of the problems observed earlier in the presentation in terms of
harmonic signal analysis.  Then, Vincent presented some proposals for
resolving the issues raised.  There was considerable debate over these
proposals with no clear consensus.  The group agreed to consider the proposals
in more detail during a SPI-2 meeting scheduled for April 18th in San Jose,
CA.

11.   Integration Issues [Lamers]

Larry Lamers reported that he had moved the SPI-2 document into Framemaker.

John Lohmeyer mentioned that the SPI-2 editing session February 6th had
polished some wording regarding the 100 ms delays following power on and bus
mode changes.  Very little else was addressed.

Due to the late hour, this topic was deferred to the next meeting.

12.   Bus Set Delay Reduction (97-116) [Ham]

John Lohmeyer reported for Symbios that some old silicon will have a problem
with a reduction in Bus Set Delay, but new silicon will have no problem with
the 200 ns. reduction Bill originally proposed.  Norm Harris reported a
similar opinion for Adaptec.  George Penokie indicated that he would need more
time to review the proposal with his engineers.

Skip Jones suggested that the lower value be tied to a negotiated bus transfer
period value or an operating mode, e.g. LVD.  John Lohmeyer and Larry Lamers
described how the bus set delay affects arbitration, which has no functional
tie to bus speed.  The group discussed the history of similar changes in SCSI.

Larry asked that the committee 1) define a mechanism for insuring that the bus
set delay is known, and 2) work to lower bus set delay and arbitration
overhead as much as possible.  The group discussed this viewpoint at length,
however, no clear resolution was reached.

13.   Hot-Plugging Data (97-144r0) [Ham]

Bill presented data showing glitches produced by hot-plugging in laboratory
tests.  While preliminary, the device under test did not respond to the hot
plugging glitches.

In response to questions from the group, Bill provided details of how the
tests were conducted.  Bill said that additional tests are necessary and
agreed to report information to the group at the next bi-monthly meeting.

14.   REQ/ACK Glitch Filters [Ham]

Bill Ham raised concerns about coordinating REQ/ACK counting and data
latching.  He expressed the worry that the use of different circuits for the
two tasks can cause the two functions to be performed differently.  The group
discussed Bill's concerns.  Some group members worried that attempts to
address the problem by making changes in the standard would result in the
standard specifying a specific implementation.  Bill suggested that specifying
a noisy signal and the parameters of how a receiver must respond to that
signal might produce the desired results.

The group also discussed REQ/ACK Offset.  Bill noted that, for optimal
performance, REQ/ACK Offset needs to double every time the basic bus speed
doubles.  Otherwise, the synchronous transfers will stall due to inadequate
FIFO space.  Some group members objected to Bill's assertion, since large
FIFOs can be expensive.

Based on a request made at the January meeting, George Penokie asked that the
group consider defining a range on the time interval that glitch filtering is
applied.  For example, he requested a range of 6-10 ns. for 10 mega-transfers,
4-7 ns. for 20 mega-transfers, and 1-4 ns. for 40 mega-transfers.  John
Lohmeyer recalled that the numbers discussed at the January were intended to
be minimums and that the maximum is what ever can be done up to the point
where the device fails to meet its setup and hold times.  This returned the
numbers to the  10 ns., 7 ns., and 4 ns. numbers discussed at the January
meeting.

15.   Meeting Schedule

The group decided to cancel the planned meeting of SPI-2 Editors previously
scheduled for Thursday April 10, 1997.  However, a working group meeting to
discuss Ultra3 SCSI issues was scheduled on Friday April 18, 1997 in San Jose,
hosted by Norm Harris of Adaptec.  A subsequent general SPI-2 working group
meeting was scheduled for Monday May 5, 1997 in Natick, MA.

16.   Adjournment

The meeting was adjourned at 4:50 p.m. on Monday March 10, 1997.

--
John Lohmeyer                 E-Mail: john.lohmeyer at symbios.com
Symbios Logic Inc.             Voice: 719-533-7560
4420 ArrowsWest Dr.              Fax: 719-533-7036
Colo Spgs, CO 80907-3444    SCSI BBS: 719-533-7950 300--28800 baud

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