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:
* "Lohmeyer, John" <JLOHMEYE at COSSYMWEST.CO.SYMBIOS.COM>
*
Minutes of SPI-2, SPI-Amendment, & SES Working Group
X3T10/96-257r0
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
Agenda
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)
[Moore]
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
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:
3. Attendance and Membership
Attendance at working group meetings does not count toward minimum
attendance
requirements for X3T10 membership. Working group meetings are open to
any
person or organization directly and materially affected by X3T10'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. Richard Moore V Adaptec, Inc.
richard_moore at corp.adaptec
.com
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.
com
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.
com
Mr. Roger Cummings P Distributed Processing
cummings_roger at dpt.com
Tech.
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.
seagate.com
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
Co
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
are
affected by a signal coupling effect, which affects the signal impedance.
He
noted the different coupling properties of the single-ended and
differential
signaling technologies. The distance between the traces appeared to be
the
major variable in the design. The group needed a lengthy discussion to
become
educated in the electrical subtleties electro-mechanical properties of
circuit
boards and the computer programs that model them. Larry's concluding
statement was, "Without violating any standard construction practices, we
can
develop a backplane design that supports both single-ended and
differential
signaling."
Bill Ham complemented Dean Wallace on the stacked trace design, shown in
his
handouts. Bill also noted that two organizations have independently
established the feasibility of designing a universal backplane. Bill
noted
that established the general practicality of the concept.
Noting that standards committees do not design products, John questioned
what
the goal of the committee should be in this case. Bill proposed that an
informative annex or even a brief paragraph of informative exposition
should
be added to the standard. Gene Milligan said he, in general, is opposed
to
adding annexes to standards. It was not clear from the discussion who,
if
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
results
of the last meeting (96-253) and Bill Ham's document (96-252) describing
three
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
line
affects operation of a SCSI device. The focal point of George's concern
is
that an LVD device must be able to continue to operating when a single
ended
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
timing
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
work
on LVD SCSI. John reported that his colleagues have tested SCAM on LVD
SCSI
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
its
relationship to SCAM and active/passive negation. Possibly, a row needs
to be
added covering SCAM, which requires passive-negation on additional
signals
(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
EPI
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
any
new requirements). The group discussed how best to inform the
world-at-large
of the challenges in mixing 8-bit devices and 16-bit devices on a single
bus.
It was noted that bus expanders are particularly helpful in this area.
The group generally disliked including an outright prohibition on mixing
8-bit
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
currents
(96-245), which addresses concerns raised by Gene Milligan at the
September
meeting (96-232r1). The group discussed Dean's proposal. Dean noted
several
changes in the proposal and agreed to bring a revised proposal to the
next
meeting.
4.8 SPI-2 Unified Document (SPUD) Integration Issues (see 96-253)
The group discussed the following issues related to integrating all of
the
parallel bus signaling standards into a single standard. The below list
was
developed during the recent SPI-2 editing sessions. John stated his
desire
that a broader group should review these issues.
1. Active negation - map of existence (see X3T10/95-295); map of
intensity
(use F20 envelope)
The group agreed that the wire-or'ed lines should not be actively
negated.
None of the signals used for SCAM protocol should be actively negated
during
the SCAM protocol. The group reviewed the map of existence. The group
agreed
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
re-qualify;
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
0.3
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
multi-mode
drivers.
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
connected
(SFF-8040)), signal ground and ground ground for tables defining SE
signals.
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
below),
so that work could proceed on the SES review.
6. SE Receiver - hysterisis (.3), input levels (adopt F20), pin
leakage
(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
disturbance.
10. Cable specifications - impedance (loaded & unloaded), skew, wire
gauge,
attenuation
11. Add Q-cable pinouts
12. Micro SCSI pinouts
13. Reserved lines
4.9 Error in the thresholds specified in Fig. 24 (reflector message)
[Moore]
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
Ham
remained unconvinced that any substantial changes are needed.
Gene noted that there is an assumption that the signal will continue into
the
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
produced
symmetrical signals when used with biased terminators.
Bill noted that the capacitance of the test board exceeded the SPI-2
(LVD)
requirements. Because of the capacitance problem, Bill showed how the
signal
quality is degraded and, in some cases, fails to meet the necessary
signaling
properties. Bill went on to show how even the capacitance problem data
|from a
flawed configuration demonstrates the correctness of the specified
capacitance
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
draft
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
proposed
resolutions. The first topic to generate significant discussion was
whether
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
FC-PH
identifiers.
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
is
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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