Minutes, IBIS Quality Task Group

18 January 2022

12:00-13:00 EST (09:00-10:00 PST)

ROLL CALL

ANSYS                               Curtis Clark
Intel Technology                    Michael Mirmak
Micron Technology                 * Randy Wolff
Siemens EDA                         Weston Beal
Signal Integrity Software:        * Mike LaBonte
Teraspeed Labs:                   * Bob Ross
Zuken USA:                        * Lance Wang

Everyone in attendance marked by *

NOTE: "AR" = Action Required.

-----------------------MINUTES ---------------------------
Mike LaBonte conducted the meeting.

Call for IBIS related patent disclosures:

- None


Call for opens:

- None


Review of previous meeting minutes:
Minutes from the January 11, 2021 meeting were reviewed.  Bob Ross moved to accept the
minutes.  Lance Wang seconded the motion.  Without objection, the minutes were approved.


ARs:
- AR: Mike LaBonte to investigate IBISCHK error differences calling from EMD vs. directly
  Done.
- AR: Mike LaBonte to write ibischk bug report to eliminate system calls
  Not done yet.
- AR: Mike LaBonte to update ibischk710 user guide to correct EMS references
  Done. Mike retained the document, it was not published.


NEW ITEMS:

IBISCHK710 development:
Bob Ross said the IBISCHK developer expected to send the updated message spreadsheet
shortly.  The user guide could be updated once that was received.


New parser bug reports:

BUG228:
Bob Ross said the bug report did not specify exactly what IBISCHK change we were seeking.
He said the error message correctly identified a problem, but files with [IBIS Ver] before
7.0 did not produce the message.  Mike LaBonte said we would need to decide whether to
apply the check retroactively.  Bob said signal_name was the issue.  Randy Wolff said we
might need to reread the BIRD again to be clear.  Bob said we had in the past applied some
new rules retroactively.  Randy asked for an example.  Bob said we had required thresholds
for input models retroactively.  We also had applied V-T endpoint/I-V consistency checks
retroactively.  Mike said that gave an error over some percent, a warning for less.  Mike
asked what it would take to make the bug testcase file pass, noting that the problem
involved signal names that were from the databook.  Randy said some signal renaming would
be the best solution.

Bob wondered if a .ims file testcase might encounter the same problem.  He said the
message could be confusing.  Bob recommended citing it as an EMD error in the message,
when referring to the IBIS file.  Mike suggested issuing errors for the releases requiring
the new rules, and warnings for prior release files.

Mike showed an email summarizing his findings from comprehensive testing.  He said E0730
was an error code that began with IBISCHK 7.0.0, and he found that it was printed only
when a .ibs file was checked through a .emd file.  Checking the same file directly did not
produce the error.  He felt that should not happen.  Randy said E0730 and E5808 looked
like almost the same error.  Bob asked what Arpad Muranyi's original issue was.  We needed
to go back to the emails.

Mike said he had tried 8 case, using both the released IBISCHK 7.1.0 software and one in
which he had fixed the problem where it used the .emd version for checking all files..
Mike described his code fix, which involved using a geFileVersion variable instead of
geIbisVersion, which he said was defined but previously never used.  Bob noted that the
fix suppressed the E5808 error, and he felt that should be reported.  Randy asked if only
that check depended on the version.  Lance Wang said there were a lot of other new checks
that would give errors with older version files if that was the case.  Randy asked if the
file should give both E5808 and E0730 errors, not just E5808.  Bob said it should.  Mike
said each check had it's own conditional code related to version, and only the E5808
through E5810 codes had that conditional wrong.  He said that we accidentally had a new
feature that we were thinking about asking for, but it should be coded properly.

Bob said it was a problem if an IBIS 5.1 file had an error that was not flagged.  Mike
said the file was a released IBIS 5.1 file that  had been used with no known problems
until EMD came along.  Randy said to use [Interconnect Model], the IBIS 5.1 file would
need to be upgraded anyway.  He said E5808 should be checked in versions prior to 7.0, but
there should be an explanation.  He suggested making it a warning message for pre-7.0
files.  Lance suggested checking older files against both old and new rules, to let users
see potential future problems.  Bob said a valid 5.1 file did not require [Pin Mapping],
but used with EMD we would use signal_names, and it would be OK.  Mike suggested reviewing
suggested prototypes of what the ibischk output should look like for various cases.  Randy
said we should fix the code to check retroactively, and also considering making it a
warning.  Bob said E0730 could also be issued for pre-7.0 files.

AR: Mike LaBonte to investigate why E0730 is printed only with -emd


IBIS quality checklist:
No discussion.


Tabled topics (no discussion without motion):
  - BIRD181.2
  - IBISCHK security fixes


Bob Ross moved moved to adjourn. Randy Wolff seconded. Without objection the meeting ended.

Meeting ended: 13:20 ET

Next meeting January 25, 2022
