Minutes of Fast-xx Study Group and SPI-2 Working Group

John Lohmeyer John.Lohmeyer at symbios.com
Mon Jul 21 12:17:14 PDT 1997


* From the T10 (formerly SCSI) Reflector (t10 at symbios.com), posted by:
* John Lohmeyer <John.Lohmeyer at Symbios.com>
*
Minutes of Fast-xx Study Group and SPI-2 Working Group         T10/97-209r0

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

                                             Doc. No.: T10/97-209r0
                                                 Date: July 21, 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 Fast-xx Study Group and SPI-2 Working Group
            July 14, 1997 -- Colorado Springs, CO


                                  Agenda

1. Opening Remarks

2. Approval of Agenda

3. Attendance and Membership

4. Fast-xx Study Group {Monday Morning}
   4.1 Cable Company's Presentations for Low-Attenuation Cables (97-213)
      [Rogers]
   4.2 Cable Attenuation & Margin Budget Analysis at 80 MHz (97-207) [Gintz]
   4.3 Bias Reduction Proposal (97-214) [Bridgewater]
   4.4 Dual Clocking Proposal (97-208) [Bastiani]

5. SPI-2 Working Group {Monday Afternoon}
   5.1 SPI-2 Revision 12 Review [Penokie]
   5.2 Single-ended termination (96-245r2 and 97-174r0) [Wallace, Aloisi]
   5.3 Capacitance Measurement at 2 Volts [Wallace/Ham]
   5.4 Universal Backplane Annex (97-121r0) [Wallace]
   5.5 Bus Set Delay Reduction (97-116) [Ham]
   5.6 REQ/ACK Glitch Filters [Ham]
   5.7 Latching and Counting (97-182) [Novak/Ham]
   5.8 Double ACK [Williams]

6. Meeting Schedule

7. Adjournment




                              Results of Meeting

1.    Opening Remarks

John Lohmeyer, the T10 Chair, called the meeting to order at 9:00 a.m., Monday
July 14, 1997.  He thanked Symbios 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 agenda was approved with the following additions and changes:

Items:
      4.2 First Pulse Compensation - Inter-Symbol Interference (ISI) [Lamers]
      4.3 Modeling Assumptions [Schneider]
      4.4   Figure 25 Timing for Ultra-3 [Bastiani]
      5.4 SPI-2 Integration Issues [Lamers]

were replaced with:

      4.2 Cable Attenuation & Margin Budget Analysis at 80 MHz [Gintz]
      4.3 Bias Reduction Proposal [Bridgewater]
      4.4 Dual Clock Proposal [Bastiani]
      5.1 SPI-2 Revision 12 Review [Penokie]

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. Vincent Bastiani   A# Adaptec, Inc.             bastiani at corp.adaptec.com
Mr. Lawrence J. Lamers A  Adaptec, Inc.             ljlamers at ix.netcom.com
Mr. Tak Asami          V  Adaptec, Inc.             asami at itc.adaptec.com
Mr. Bill Gintz         V  Adaptec, Inc.             bgintz at corp.adaptec.com
Mr. Wally Bridgewater  V  Adaptec, Inc.             wally at eng.adaptec.com
Mr. Tom Schneider      V  Adaptec, Inc.             schneid at itc.adaptec.com
Mr. Michael Wingard    P  Amphenol Interconnect     mikwingard at aol.com
Mr. Ron Roberts        A  Apple Computer            rkroberts at aol.com
Mr. Charles Tashbook   P  Dallas Semiconductor      charles.tashbook at dalsemi.
                                                    com
Mr. Michael Smith      A  Dallas Semiconductor      mike.smith 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. Roger Cummings     P  Distributed Processing    cummings_roger at dpt.com
                          Tech.
Mr. Don Vohar          A  Fujitsu (FCPA)            dvohar at fcpa.fujitsu.com
Mr. Zane Daggett       P  Hitachi Cable             zdaggett at hcm.hitachi.com
                          Manchester,Inc
Mr. Kirk Rogers        A  Hitachi Cable             krogers at hcm.hitachi.com
                          Manchester,Inc
Mr. George Penokie     P  IBM Corp.                 gop at us.ibm.com
Mr. Dan Colegrove      A# IBM Corp.                 colegrov at us.ibm.com
Mr. Barry H. Wiley     V  IMP, Inc.                 bhwiley at impinc.com
Mr. Dean Wallace       P  Linfinity Micro           75671.3443 at compuserve.com
Mr. Louis Grantham     A  Linfinity Micro           lgdatcom at ix.netcom.com
Mr. Alan Littlewood    P  LSI Logic Corp.           alanl at lsil.com
Mr. Pete McLean        P  Maxtor Corp.              pete_mclean at maxtor.com
Mr. Edward A. Gardner  P  Ophidian Designs          eag at ophidian.com
Mr. Skip Jones         P  QLogic Corp.              sk_jones at qlc.com
Mr. James McGrath      P  Quantum Corp.             JMCGRATH at QNTM.COM
Mr. Richard Uber       V  Quantum Corp.             duber at tdh.qntm.com
Mr. Pat McGarrah       V  Quantum Corp.             pmcgarra at tdh.qntm.com
Mr. Gene Milligan      P  Seagate Technology        Gene_Milligan at notes.
                                                    seagate.com
Mr. Daniel (Dan) F.    A# Seagate Technology        daniel_f_smith at notes.
Smith                                               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. John Lohmeyer      P  Symbios Logic Inc.        john.lohmeyer at symbios.com
Mr. Ralph O. Weber     A  Symbios Logic Inc.        roweber at acm.org
Mr. Frank Gasparik     V  Symbios Logic Inc.        frank.gasparik at symbios.com
Mr. Tracy Spitler      V  Symbios Logic Inc.        tracy.spitler at symbios.com
Mr. Andy Brown         V  Symbios Logic Inc.        andrew.brown at symbios.com
Mr. Bill Schmitz       V  Symbios Logic Inc.        bill.schmitz at symbios.com
Mr. Graeme             V  Symbios Logic Inc.        gwl at symbios.com
Weston-Lewis
Mr. Kevin Gingerich    O  Texas Instruments, Inc.   k-gingerich at ti.com
Mr. Paul D. Aloisi     P  Unitrode Corporation      aloisi at unitrode.com
Mr. Gregory Kapraun    V  Western Digital Corp.     kapraun at wdroc.wdc.com

43 People Present

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

4.    Fast-xx Study Group {Monday Morning}

4.1   Cable Company's Presentations for Low-Attenuation Cables (97-213)
[Rogers]

Kirk Rogers (Hitachi Cable) presented 97-213 showing test results for several
types of cables as a function of transmission frequency.  The group discussed
choices and options for cable configurations for high-bandwidth SCSI signal
transmission.  Kirk noted that he has no conclusions based on the data
presented.  He said that, in the absence of in guidance from T10, he will
continue the investigation with the effects of insulation on transmission
performance.

4.2   Cable Attenuation & Margin Budget Analysis at 80 MHz (97-207) [Gintz]

Bill Gintz presented 97-207, an analysis of amplitude and skew budgets at 80
mega-transfers per second.  He offered clocking on the leading and trailing
edge of signals (double clocking, or dual clocking) as a viable (perhaps
preferred) method for reaching 80 mega-transfers per second.  Bill Ham, Bill
Gintz, and a few others discussed the electronics design and signaling
properties behind the values in the overview table presented.  Gene Milligan
and John Lohmeyer agreed that double clocking should be considered seriously
by the group.

4.3   Bias Reduction Proposal (97-214) [Bridgewater]

Wally Bridgewater presented a proposal that the bias voltage be reduced, 97-
214.  He cited several other data transmission methods as evidence that the
bias voltage should be kept as small as possible.  From his literature search,
Wally concluded that the desirable ratio is 10 to 1.  Wally presented a table
of four specific items, whose sum defines bias voltage.  The group discussed
the specific values Wally gave for each of the four items and adjusted some of
the values.  Wally agreed revise his proposal based on the group's discussion.

4.4   Dual Clocking Proposal (97-208) [Bastiani]

Vince Bastiani presented a detailed proposal containing four specific items
leading to using dual clocking (a.k.a. double clocking) as the mechanism for
reaching a total bandwidth of 80 mega-transfers per second (97-208).  Gene
Milligan asked that the group begin calling the "first pulse problem" the
inter-symbol interference (ISI) problem, thus using the more commonly accepted
terminology, and there were no objections.  Vince proposed reducing the multi-
point cable distance to 6 m and the group discussed the proposed reduction.

The group got bogged down in the nomenclature for dual clocking, but agreed to
defer the discussion to later in the agenda, or another agenda (possibly the
STA Technical Committee meeting).

Several edits were made to Vince's slides during the presentation (e.g. the
ISI change).  Vince agreed to provide a revised copy of the presentation for
the mailing, with help from Larry Lamers.

5.    SPI-2 Working Group {Monday Afternoon}

5.1   SPI-2 Revision 12 Review [Penokie]

John announced that George Penokie had completed the first draft the fully
integrated SPI-2 document (SPI-2 revision 12).  George led a review of the
document, with a particular focus on the 35 editor's notes identifying areas
where he found issues during the integration process.  George asked all
reviewers to inspect carefully for errors in the tables he added to summarize
the characteristics of the several transfer-rate variations of parallel SCSI.

Bill Ham asked the group to consider the goal for the contents of SPI-2.  He
started the postulate that only the highest performance properties (cable
capacitance, terminator construction, et. al.)  be present in SPI-2.  George
represented the opposing view that all defined properties be included and
properly identified with the particular SCSI variation (or variations) to
which they apply.  Gene Milligan, Larry Lamers, Dean Wallace, and several
others discussed aspects of this goal.  At some times during the discussion,
the question was stated in terms of whether SPI-2 will supersede all previous
parallel SCSI documents. With regard to superseding previous documents, it was
noted that the T10 Plenary has taken no action regarding retiring older
parallel SCSI documents and that the SPI-2 project was set up as a new
standards project, not a revision to SPI.  Consequently, none of the existing
standards will be automatically withdrawn upon SPI-2's approval.

No specific resolution was reached regarding the goal for SPI-2.  George asked
the group press on with the review and consider what information should be
included in SPI-2 on a case-by-case basis.

George received many comments and suggestions for improvements, noted
corrections for the next SPI-2 revision, and agreed to provide the next SPI-2
revision containing all noted corrections prior to the next meeting.

The working group recommended that the plenary approve removal of the cable
impedance requirements for Slow parallel SCSI from SPI-2.  In addition, Bill
Ham strongly recommended that the Fast-10 cable impedance data be removed too.

5.2   Single-ended termination (96-245r2 and 97-174r0) [Wallace, Aloisi]

Dean and Paul agreed to defer this topic to the next meeting.

5.3   Capacitance Measurement at 2 Volts [Wallace/Ham]

Dean agreed to defer this topic to the next meeting.

5.4   Universal Backplane Annex (97-121r0) [Wallace]

Dean agreed to defer this topic to the next meeting.

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

Bill Ham described the need for reducing Bus Set Delay from 1800 nsec to 1600
nsec.  Bill explained how the effect of Bus Set Delay concerns only bus
configurations that contain repeaters, i.e., how traditional single-segment
busses cannot be affected by the change in Bus Set Delay.  The only case that
might lead to trouble is when an old device with a Bus Set Delay of 1800 nsec
is used in a maximum-length expander application.  EPI will make such
configurations illegal by requiring that all devices used in a maximum-length
expander application have a Bus Set Delay of 1600 nsec or less.  However, if
an old device is used anyway, it could lead to more than one device assuming
it won arbitration (an infrequent failure mode).

Jim McGrath walked the group through the cases of what will happen when
multiple devices `win' arbitration.  He strongly suggested that all the cases
work out to recoverable errors, where either a functional selection occurs or
a selection timeout occurs.   Larry Lamers noted that the requirement in
clause 6.1.3 in SCSI-2 (which prohibits proceeding with a selection when three
IDs are asserted or parity is incorrect) forms the basis of the assurance that
the proposal has no adverse affects on old devices.

The group unanimously recommended that the plenary approve reducing Bus Set
Delay from 1800 nsec to 1600 nsec in SPI-2.

5.6   REQ/ACK Glitch Filters [Ham]

Bill Ham agreed to include this topic in the EPI discussion on Tuesday
morning.

5.7   Latching and Counting (97-182) [Novak/Ham]

Vit Novak was unable to attend this meeting.  Bill Ham agreed to include this
topic in EPI discussion on Tuesday morning.

5.8   Double ACK [Williams]

Bill Ham agreed to include this topic in the EPI discussion on Tuesday
morning.


6.    Meeting Schedule

The next meeting of Fast-xx Study Group and SPI-2 Working Group will be
September 8, 1997, in Nashua, NH at the Crowne Plaza Nashua Hotel (603-886-
1200), hosted by Unitrode.

7.    Adjournment

The meeting was adjourned at 6:50 p.m. on Monday July 14, 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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