Minutes of SPI-2, SPI-Amnd, & SES WG - 11/4/96

Lohmeyer, John JLOHMEYE at cossymwest.co.symbios.com
Tue Nov 12 14:25:00 PST 1996

* From the SCSI Reflector (scsi at symbios.com), posted by:

Minutes of SPI-2, SPI-Amendment, & SES Working Group   

Accredited Standards Committee*
X3, Information Technology
                                             Doc. No.: X3T10/96-257r0
                                                 Date: 12 November, 1996
                                              Project: 1142-D
                                            Ref. Doc.:
                                             Reply to: John Lohmeyer

To:         Membership of X3T10

From:       Ralph Weber, Secretary X3T10
            Larry Lamers, Vice-chair X3T10
            John Lohmeyer, Chair X3T10

Subject:    Minutes of SPI-2, SPI-Amendment, & SES Working Group
            November 4, 1996 -- Palm Springs, CA


1. Opening Remarks

2. Approval of Agenda

3. Attendance and Membership

4. SPI-2 Topics
   4.1 Universal backplane [Wallace/Barnes]
   4.2 LVD case 4 hot plugging [Barnes]
   4.3 Changing driver modes when hot plugging [Penokie]
   4.4 LVD SCAM issues [Penokie]
   4.5 Mixing 8- and 16-bit buses at Fast-40 speeds [Bridgewater]
   4.6 HVD Fast-40 (96-190) [Gingerich]
   4.7 Single-ended termination (96-245) [Wallace]
   4.8 SPI-2 Unified Document (SPUD) Integration Issues (see 96-253)
   4.9 Error in the thresholds specified in Fig. 24 (reflector message)
   4.10 LVD Testing Results [Ham]

5. SPI Amendment #1 review [Lamers]

6. SES document review (96-249r0) [Snively]

7. Meeting Schedule

8. Adjournment

                              Results of Meeting

1.    Opening Remarks

John Lohmeyer, the X3T10 Chair, called the meeting to order at 9:00 a.m.,
Monday November 4, 1996.  He thanked Norm Harris of Adaptec for hosting   

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

2.    Approval of Agenda

The agenda was approved with the following additions:

3.    Attendance and Membership

Attendance at working group meetings does not count toward minimum   
requirements for X3T10 membership.  Working group meetings are open to   
person or organization directly and materially affected by X3T10's scope   
work.  The following people attended the meeting:

         Name          S        Organization         Electronic Mail   
 ---------------------- -- -------------------------   
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. Richard Moore      V  Adaptec, Inc.   
            richard_moore at corp.adaptec
Mr. Edward Fong        P  Amdahl Corp.   
             esf10 at amail.amdahl.com
Ms. Lisa Huff          V  AMP, Inc.                 lisa.huff at amp.com
Mr. Louis Grantham     P  Dallas Semiconductor      grantham at dalsemi.com
Mr. Greg McSorley      O  Data General Corp.   
       greg_mcsorley at dgc.ceo.dg.
Dr. William Ham        A# Digital Equipment Corp.   
  ham at subsys.enet.dec.com
Mr. Douglas Hagerman   A# Digital Equipment Corp.   
  hagerman at starch.enet.dec.
Mr. Roger Cummings     P  Distributed Processing   
   cummings_roger at dpt.com
Mr. George Penokie     P  IBM Corp.   
                gop at rchvmp3.vnet.ibm.com
Mr. Dan Colegrove      A# IBM Corp.   
                colegrove at vnet.ibm.com
Mr. Dean Wallace       P  Linfinity Micro   
          75671.3443 at compuserve.com
Mr. Evgeny Jake Berzon O  NEC Electronics, Inc.   
    jberzon at asic.mtv.nec.com
Mr. Edward A. Gardner  P  Ophidian Designs          gardner at acm.org
Mr. Tom Jones          A# QLogic Corp.              t_jones at qlc.com
Mr. John A. Fobel      O  Rancho Technology, Inc.   johnf at rancho.com
Mr. Gene Milligan      P  Seagate Technology        Gene_Milligan at notes.
Mr. Dave Guss          P  Silicon Systems, Inc.   
    dave.guss at tus.ssi1.com
Mr. Robert N. Snively  P  Sun Microsystems Computer   
bob.snively at eng.sun.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. Larry Barnes       V  Symbios Logic Inc.   
       larry.barnes at symbios.com
Mr. Kenneth J. Hallam  P  UNISYS Corporation   
       ken.hallam at mv.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         549.9900 at mcimail.com

30 People Present

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

4.    SPI-2 Topics
4.1   Universal backplane [Wallace/Barnes]

Larry Barnes presented background information necessary to understand the
design of signal carrying backplanes.  He showed how differential signals   
affected by a signal coupling effect, which affects the signal impedance.   
noted the different coupling properties of the single-ended and   
signaling technologies.  The distance between the traces appeared to be   
major variable in the design.  The group needed a lengthy discussion to   
educated in the electrical subtleties electro-mechanical properties of   
boards and the computer programs that model them.  Larry's concluding
statement was, "Without violating any standard construction practices, we   
develop a backplane design that supports both single-ended and   

Bill Ham complemented Dean Wallace on the stacked trace design, shown in   
handouts.  Bill also noted that two organizations have independently
established the feasibility of designing a universal backplane.  Bill   
that established the general practicality of the concept.

Noting that standards committees do not design products, John questioned   
the goal of the committee should be in this case.  Bill proposed that an
informative annex or even a brief paragraph of informative exposition   
be added to the standard.  Gene Milligan said he, in general, is opposed   
adding annexes to standards.  It was not clear from the discussion who,   
anyone, would carry this idea further.

4.2   LVD case 4 hot plugging [Barnes]

Larry Barnes stated that his simulation results would have to be   
postponed due
to a simulator failure over the weekend.  The committee reviewed the   
of the last meeting (96-253) and Bill Ham's document (96-252) describing   
ways to do case 4 hot plugging in LVD SCSI.

4.3   Changing driver modes when hot plugging [Penokie]

George Penokie reviewed problems in the description of how the DIFFSENS   
affects operation of a SCSI device.  The focal point of George's concern   
that an LVD device must be able to continue to operating when a single   
device is connected to the bus.  George agreed to write a proposal for
consideration at the next meeting calling for establishment of a Unit
Attention condition when a change in the DIFFSENS state is detected.

John Lohmeyer asked a question about the 100 msec driver mode change   
specification.  The group discussed the intent of the current wording,
reviewed past arguments in this area, and did not reach a conclusion.

4.4   LVD SCAM issues [Penokie]

George Penokie had questioned via a reflector message whether SCAM will   
on LVD SCSI.  John reported that his colleagues have tested SCAM on LVD   
and it works.  George noted that wording to this effect should be added   
to the
SCAM description in SPI-2.

It was noted that the SPI-2 technical editor should review table 14, for   
relationship to SCAM and active/passive negation.  Possibly, a row needs   
to be
added covering SCAM, which requires passive-negation on additional   
(including MSG, C/D, I/O, and the data bus).

4.5   Mixing 8- and 16-bit buses at Fast-40 speeds [Bridgewater]

Wally Bridgewater raised a concern about capacitance matching when 8-bit
devices are installed in the middle of a 16-bit bus.  Bill Ham noted that   
is addressing these issues.  Bill felt that no additional wording is   
needed in
the current standards (Note: EPI is a technical report that provides an
additional description of the existing standards but does not standardize   
new requirements).  The group discussed how best to inform the   
of the challenges in mixing 8-bit devices and 16-bit devices on a single   
It was noted that bus expanders are particularly helpful in this area.

The group generally disliked including an outright prohibition on mixing   
and 16-bit devices in SPI-2.  However, the group desired that suitable
pointers to the EPI discussions of mixed bus widths be added to SPI-2.

4.6   HVD Fast-40 (96-190) [Gingerich]

In Kevin Gingerich's absence, the group discussed what they thought was
Kevin's issue.  With little hard information to discuss, Gene Milligan
proposed this item be dropped from the agenda.  In the absence of any
objections, this item will be removed from future agendas.

4.7   Single-ended termination (96-245) [Wallace]

Dean Wallace presented a proposal for changes in SPI-2 regarding sink   
(96-245), which addresses concerns raised by Gene Milligan at the   
meeting (96-232r1).  The group discussed Dean's proposal.  Dean noted   
changes in the proposal and agreed to bring a revised proposal to the   

4.8   SPI-2 Unified Document (SPUD) Integration Issues (see 96-253)

The group discussed the following issues related to integrating all of   
parallel bus signaling standards into a single standard.  The below list   
developed during the recent SPI-2 editing sessions.  John stated his   
that a broader group should review these issues.

1.    Active negation - map of existence (see X3T10/95-295); map of   
   (use F20 envelope)

   The group agreed that the wire-or'ed lines should not be actively   
   None of the signals used for SCAM protocol should be actively negated   
   the SCAM protocol. The group reviewed the map of existence.  The group   
   to remove the setup phase from the table.

2.    SE termination, max/min current & sinking of current (see X3T10/96-
   222r1); suggest min current 20 milliamps at 0.2 v DC and a max of 25.4
   milliamps at 0.2 v DC;  don't require driver to sink this to avoid   
   add a min at 0.5 v DC; how to deal with non-linear terminators; do we   
need a
   duty-cycle spec? suggest 20 asserted signals for wide, 12 on narrow,   
37 on 32-
   bit.  Add exception for a contained bus (e.g., laptop) of less than   
   meters. Add a 12.5 pf max capacitance for terminator.

   Dean Wallace and Paul Aloisi agreed to work on a duty cycle proposal,   
to be
   incorporated in Dean's other termination proposal.

3.    Leakage spec increased for LVD multi-mode drivers to 20 micro-amps   
   Resolve by specifing one for each driver type.

   The group agreed that leakage current needs to be specified for LVD   

4.    Latching & counting - require that they be an atomic action for hot
plugging - possibly an annex or implementation note.

The group discussed the proposal and agreed to review the wording, when
someone brings it in.

5.    Ground - power, logic & ground drivers (25-pin power & ground   
   (SFF-8040)), signal ground and ground ground for tables defining SE   

   The group discussed how various ground lines are named in the standard   
and how
   that can be tied together.

   At this point, the group deferred action on the remaining items (shown   
   so that work could proceed on the SES review.

6.    SE Receiver - hysterisis (.3), input levels (adopt F20), pin   
   (same), glitch filtering (enable of first detection of a transition   
for 'x'
   duration).  Need an algorithm to determine 'x'.
7.    SE Drivers - slew rate (use F20 specs);
8.    16 or 32 devices? 32-bit data path? Is it a single segment draft?
   Should expanders be included?  Suggest that SPI-2 is 16 loads per   
segment max;
   allow 32-bit data path and 32 SCSI IDs addressability when using VHDCI
   connectors with primary and secondary cables
9.    Case 4 hot plugging - requires SCA-2 connectors to allow   
pre-charge, a
   resistive contact may also work, needs research to determine max   
10.   Cable specifications - impedance (loaded & unloaded), skew, wire   
11.   Add Q-cable pinouts
12.   Micro SCSI pinouts
13.   Reserved lines

4.9   Error in the thresholds specified in Fig. 24 (reflector message)   

Richard Moore discussed concerns in table 19 with Bill Ham.  Wally
Bridgewater, Larry Barnes, and several others joined the discussion, all
trying to show how table 19 and figure 24 contents may or may not need
revision.  Richard agreed to reconsider his concerns, and possibly post a
counter-example on the SCSI reflector.  Throughout the discussion, Bill   
remained unconvinced that any substantial changes are needed.

Gene noted that there is an assumption that the signal will continue into   
transition region, as it really started in the transition region.

4.10  LVD Testing Results [Ham]

Bill Ham presented his first test results with "real, full protocol" LVD
parts.  Bill noted that this was his first chance to examine the   
operation of
fully asymmetrical drivers.  As expected, the asymmetrical drivers   
symmetrical signals when used with biased terminators.

Bill noted that the capacitance of the test board exceeded the SPI-2   
requirements.  Because of the capacitance problem, Bill showed how the   
quality is degraded and, in some cases, fails to meet the necessary   
properties.  Bill went on to show how even the capacitance problem data   
|from a
flawed configuration demonstrates the correctness of the specified   
requirements.  Bill also demonstrated how the data suggests ultimate
successful operation of LVD SCSI in our specified configurations (when
the capacitance problem is factored out).

Bill's summary points were: 1) Asymmetric signaling compensates for the
terminator bias, 2) misconfigured  termination resulting from excessive
capacitance dominates performance, and 3) the configuration rules in the   
standard are confirmed by this testing.

5.    SPI Amendment #1 review [Lamers]

The group agreed to hold a walk-through review of the SPI Amendment   
during the
general working group meeting.

6.    SES document review (96-249r0) [Snively]

Bob Snively led a review of the letter ballot comments and on the   
resolutions.  The first topic to generate significant discussion was   
to require the use of FC-PH world-wide unique identifiers in several key
diagnostic page formats.  It was agreed to continue requiring the use of   

7.    Meeting Schedule

The next meeting of SPI-2 Working Group is scheduled for Thursday   
December 5,
1996 in Bloomington , MN with X3T11 hosted by IBM.  A subsequent meeting   
planned for Monday January 6, 1997 in Dallas, TX.

8.    Adjournment

The meeting was adjourned at 5:17 p.m. on Monday November 4, 1996.

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--14400 baud

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