[fitsbits] IAU-FWG approval of 64-bit integers in FITS

[William Pence]

I am pleased to announce that the 22-member IAU FITS Working Group has voted 
in favor of adding support for various forms of 64-bit integers in FITS 
files.  In particular the IAU-FWG unanimously approved immediate support for 
2 new types of columns in FITS binary tables:

1) columns containing 64-bit signed integer values, which will be recognized 
by a TFORMn keyword type of 'K' (analogous to columns of 32-bit integer 
values that have a TFORMn type of 'J')

2) 64-bit descriptor columns with a TFORM keyword type of 'Q' which will 
support a variable-length array heap much larger than the ~2 GB limit of the 
analogous 32-bit 'P' descriptor columns.

The IAU-FWG also conditionally approved support for 64-bit integer FITS 
primary arrays or image extensions with BITPIX = 64, by a vote of 19 'Yes', 
2 'No', and 1 'Abstain'.  According to the voting rules governing the 
IAU-FWG, the 2 'No' votes force a mandatory 6-month delay (until 8 June 
2006) before this vote will be considered final.   The purpose of this 
6-month delay is to ensure that minority opinions are adequately considered 
and to provide an opportunity to try to develop a compromise that the entire 
IAU-FWG can agree on.  I will post another message here at the end of this 
6-month period to announce the final results.

More details and background information about these 64-bit integer issues 
may be found on the FITS Support Office web page at 
http://fits.gsfc.nasa.gov/fits_64bit.html.

Bill Pence
Chairman, IAU-FWG
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____________________________________________________________________
Dr. William Pence                          William.D.Pence at nasa.gov
NASA/GSFC Code 662         HEASARC         +1-301-286-4599 (voice)
Greenbelt MD 20771                         +1-301-286-1684 (fax)