[wfc] 64-bit regional vote imminent

[Arnold Rots]

Dear WFC members,

It looks like Bill Pence (IAU FWG) will issue a call for votes in the
regional FITS committees fairly soon on the issue of 64-bit support.

This message is a heads-up for that call.  Since this is summer time,
the voting period will probably extend into September.

Most likely, the regional committee members will be asked to vote 
separately on 4 specific issues to provide as much guidance as possible to 
the IAU-FWG:

1)  Do you favor adding support to FITS for primary array images and image 
extensions containing  64-bit integer pixels (with BITPIX = 64)?

2) Do you favor adding support to FITS for 64-bit descriptor 'Q' columns in 
binary tables (analogous to the 32-bit 'P' descriptor columns) to support 
FITS files with a variable length array heaps much larger than 2 GB in size?

3) Do you favor adding support to FITS for columns of 64-bit integer values 
in binary tables, with TFORMn = 'K'?

4) Do you support changing the definition of the 'P' descriptor pointers 
from 'signed integers' to 'unsigned integers'. This change would not 
invalidate any existing FITS files and would double the maximum allowed size 
of the variable length heap from ~2 GB to ~4 GB.

A PDF file available from http://fits.gsfc.nasa.gov/fits_64bit.html shows 
in detail the 11 modifications that would need to be made to the FITS 
Standard to support all these changes.


Let me know if you see something seriously wrong with this scenario
(better now than when the call for votes has gone out).

Cheers,

  - Arnold

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Arnold H. Rots                                Chandra X-ray Science Center
Smithsonian Astrophysical Observatory                tel:  +1 617 496 7701
60 Garden Street, MS 67                              fax:  +1 617 495 7356
Cambridge, MA 02138                             arots at head.cfa.harvard.edu
USA                                     http://hea-www.harvard.edu/~arots/
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