[fitsbits] 64-bit integers

[William Pence]

Bill,

I'm glad you raised this issue because there has been considerable recent 
activity regarding 64-bit integers in FITS.  Hopefully, in the next day or 2 
a web page will be available that summarizes the current status and provides 
some background information, as well as a more detailed proposal of specific 
changes that could be made to the wording of the FITS Standard to support 
64-bit integers. No doubt many people would like to express their opinions 
on this issue, but it may be better to wait until this web page is released 
(I'll post an announcement here) before starting a general debate of this issue.

Bill Pence

William Thompson wrote:
> Folks:
> 
> I've recently been asked whether my binary table software for IDL could 
> handle 64-bit integers, and had to respond that FITS does not currently 
> support them. I remember that there was discussion a while back about 
> adding support, but the last message I could find on the subject was 
> from October 2001, reproduced below.
> 
> It's probably about time to revisit the subject.  Personally, I can only 
> speak from the perspective of IDL.  64-bit integers were first 
> introduced into IDL in vresion 5.2, which was released in late 1998.  In 
> 2001, that would still have been a fairly recent change, but nowadays we 
> tend to consider anything before IDL 5.2 (and sometimes 5.4) too old to 
> be supported.
> 
> In the spirit of supporting innovations on a trial basis, as Bill Pence 
> mentions below, I could certainly add support for 64-bit integers into 
> my software.  The obvious implementation would be to use BITPIX=64 in 
> primary HDUs and IMAGE extensions, and TFORM='nK' in binary tables.  
> Does anybody see any problems with that?
> 
> Bill Thompson

-- 
____________________________________________________________________
Dr. William Pence                          William.D.Pence at nasa.gov
NASA/GSFC Code 662         HEASARC         +1-301-286-4599 (voice)
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