IBIS BIRD46 on FILE NAMES

                       Buffer Issue Resolution Document (BIRD)

BIRD ID#: 46
ISSUE TITLE: Relaxation of some IBIS model file name restrictions.
REQUESTOR: Matthew Flora and Kellee Crisafulli, HyperLynx
DATE SUBMITTED: 4 Dec 1997
DATE ACCEPTED BY IBIS OPEN FORUM: Pending

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STATEMENT OF THE ISSUE:

      The file names of IBIS models are currently limited to 8 characters in
      length (not counting the mandatory .ibs extension) and "must conform to
      DOS rules".

      We propose that the length limit be expanded to 64 characters and that
      periods be allowed within the file name.

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STATEMENT OF THE RESOLVED SPECIFICATIONS:
      Item 3 in Section 3 of the IBIS 3.0 specification, General Syntax Rules
      and Guidelines, currently states:

      3) File names used in the file must only have lower case characters to
          enhance UNIX compatibility and must conform to DOS rules. (The
          length of a file name should not exceed eight plus three characters
          and it must not contain special characters that are illegal in DOS).

      We propose that this item would be changed to state:

      3) File names used in the file must only have lower case characters to
          enhance UNIX compatibility. The length of a file name should not
          exceed sixty-four. This number includes the four characters of the
          mandatory file extension ".ibs". File names must not contain
          special characters that are illegal in DOS other than periods.
          Periods may be used throughout the file name, not just to mark the
          file extension. The following examples are legal names:
            82374eb.ibs
            redoct_12cmos50_a50_d50.ibs
            gtl.q612mea.ibs

      The [File Name] keyword would be updated to state:

|=============================================================================
| Keyword: [File Name]
| Required: Yes
| Description: Specifies the name of the IBIS file.
| Usage Rules:
| The file name must not be longer than 64 characters (including
| the extension). The file name must not use characters that
| are illegal in DOS other than periods. In addition, the file
| name must be all lower case, and use the extension ".ibs".
| The file name must be the actual name of the file.
|-----------------------------------------------------------------------------

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ANALYSIS PATH/DATA THAT LED TO SPECIFICATION:

      We believe that engineers have moved beyond DOS as an engineering
      platform. Therefore, we would like to lift some of the restrictions
      that were imposed by DOS.

      We already encounter IBIS model files which violate the 8.3 length rule.
      Extending the allowed length of file names gives model creators the
      opportunity to use more descriptive file names. The choice of 64
      characters was arbitrary, however names longer than that may not display
      well in applications. The limit should not be increased to more than
      255, since that would be illegal under Windows NT, Windows 95, and some
      versions of UNIX.

      Allowing the use of periods throughout file names is common in the
      majority of file systems and is another means of making file names more
      descriptive.

      Since some operating systems (Windows NT 4.0 for one) still ignore the
      case of characters in file names, file names should still be required to
      be all lower-case.

      As far as we are aware, DOS has the largest set of characters which are
      not allowed in file names. Continuing to disallow all of those
      characters (bar one - the period) should ensure that IBIS model file
      names are still valid on all common platforms.

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ANY OTHER BACKGROUND INFORMATION:

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Received on Thu Dec 4 18:44:45 1997