[fitsbits] voting results on 64-bit integer issues

[William Pence]

The 4 regional FITS committees were recently asked to vote on 4 questions to
provide guidance to the IAU FITS Working Group on whether it should modify
the FITS Standard to officially support 64-bit integer data in FITS files.
This message summarizes the results of these votes by the regional committees.

The 4 questions that the committee members were asked to vote on were:

   1) Do you favor adding support to FITS for primary arrays 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).
      This will support FITS files with a variable length array heap much
      larger than the 2 GB limit of 'P' descriptor columns.

   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 will not
      invalidate any existing FITS files and will double the maximum allowed
      size of the variable length heap from ~2 GB to ~4 GB.


The following table gives the vote tallies on these 4 questions for each of
the regional FITS committees.  The column headings for each committee are:

         NA = North American FITS committee
         E  = European FITS committee
         J  = Japanese FITS committee
         A  = Australia/New Zealand FITS committee  (this committee
              normally has 7 members, but 1 member took a temporary
              leave of absence).



           Question 1       Question 2       Question 3      Question 4
           BITPIX=64      'Q' descriptors     TFORM='K'      Unsigned 'P'
          ------------    --------------   ------------     ---------------
          NA  E  J A TOT | NA  E  J A TOT | NA  E  J A TOT | NA  E  J A TOT
Yes      13  6 10 6 35  | 13 10 10 6 39  | 13 10 10 6 39  | 11  1 10 4 26
No        0  3  0 0  3  |  0  0  0 0  0  |  0  0  0 0  0  |  0  8  0 1  9
Abstain   0  1  0 0  1  |  0  0  0 0  0  |  0  0  0 0  0  |  2  1  0 1  4
No Vote   3  2  1 0  6  |  3  2  1 0  6  |  3  2  1 0  6  |  3  2  1 0  6
          -----------------------------------------------------------------
Total    16 12 11 6 45  | 16 12 11 6 45    16 12 11 6 45    16 12 11 6 45


It is clear from the unanimous 'Yes' votes on questions 2 and 3 that these 2
issues are non-controversial.  There was some division on questions 1 and 4,
however, especially in the European committee.  The IAU FITS Working Group
will need some time to fully digest these results before deciding on whether
(and how much) to modify the FITS Standard to support 64-bit integers.  The
implications of these results will also be one of the topics of discussion
at the FITS 'Birds-of-a-Feather' session at the ADASS meeting on October 3.
-- 
____________________________________________________________________
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)