[Imgcif-l] proposed change in first line of imgcif files

[Herbert J. Bernstein]

There was an informal meeting to discuss imgCIF at the IUCr
Congress in Osaka on 26 August 2008.  Details of the
discussion will follow in future nessages.  This message
will summarize a proposal for a change in the first line
of all CBF/imgCIF files that are not fully populated
with all the imgCIF tags needed for processing by mosflm
and adxv.

1.  What problem is being solve?.  As the use of imgCIF
has increased, two very distinct sets of files have appeared:
the "miniCBFs" used for the Pilatus 6m detector and 
more fully populated imgCIF files, such as the ones
produced for ADSC detectors.  While the information
necessary for processing can be discovered from context
in handling a miniCBF, it may be necessary to read fairly
far into the file to discover that the file is indeed a
miniCBF, complicating the design of reading software.

2.  The proposed solution.  Currently CBF files begin
with a magic number comment line
            1         2         3         4         5
   12345678901234567890123456789012345678901234567890
   ###CBF: VERSION n.m

We propose to extend the magic number comment line with
two optional fields to read

            1         2         3         4         5
   12345678901234567890123456789012345678901234567890
   ###CBF: VERSION n.m     style     style_version

where "style" is a unique CBF style identifier left
justified as a single word in columns 25-34 and
"style_version" is a left justified integer in
columns 35-44.

Each style will be registered in a central repository
along with information on the tags that will be
carried forthat stye and a template of the  tags
that would be needed to fully populate the file.

More details will follow on this list and on the
CBFlib wiki after the Osaka meeting is over. 
=====================================================
  Herbert J. Bernstein, Professor of Computer Science
    Dowling College, Kramer Science Center, KSC 121
         Idle Hour Blvd, Oakdale, NY, 11769

                  +1-631-244-3035
                  yaya at dowling.edu
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