[fitsbits] Start of the CONTINUE keyword Public Comment Period

[Rob Seaman]

On Jul 14, 2007, at 6:46 PM, Craig Markwardt wrote:

> Bill, could the convention be clarified to indicate that CONTINUE  
> should not be used for keyword values that could fit in a single  
> FITS card?

I'm not sure how one ensures this given that a continued keyword  
might later be edited.

> And/or, that CONTINUE should be avoided for standard FITS keywords?

Which are the "standard" keywords - the ones mentioned in the  
standard?  My example was a keyword from another convention.

On Jul 13, 2007, at 2:28 AM, LC's NoSpam Newsreading account wrote:

> I remind everybody that inclusion in the Registry should NOT imply  
> a discussion on the merit of a convention, but only on completeness  
> of documentation, usefulness and actual use at one or more  
> institution).

Well, every previous convention has also generated a rousing  
discussion of the merits of the proposal.  This seems rather  
healthy.  I'm also not sure what the distinction is between "merit"  
and "usefulness".

Presumably we are in a period of capturing and documenting as many  
local conventions as possible.  The bigger question is what comes  
next.  Some (I'll timidly suggest the checksum convention) seem  
mature enough to become part of the standard.  Others, as with this  
current discussion, appear to have some real issues with broad  
adoption.  Still others, like foreign encapsulation perhaps, might  
simply appear as some sort of appendix since a particular HDU either  
expresses such an object or does not.

I guess I'm also wondering whether the point of the registry is to  
capture legacy conventions or to encourage new conventions.   
Personally, I would prefer that the staid, but reliable, FITS  
standard process remain the primary focus of FITS development  
efforts.  We don't need novelty for its own sake.

> I do not think the issue of keyword ordering and repetition of a  
> keyword with same name is an issue, considering the proposed  
> modifications to the Standard,

I'm getting lost with this discussion.  What proposed modifications  
are we talking about?

> So the proper name would be "CONTINUE *Long String* Keyword  
> Convention" or "OGIP 1.0 *Long String* Keyword Convention"

I disagree.  Continuation is only one possible way to implement a  
long string capability.  To be truly useful, a general facility for  
representing long strings needs to be applicable to any string valued  
keyword.  On the other hand, continuing a keyword appears to have  
some real complications - some esoteric, like the need to preserve 32- 
bit alignment within ASCII encoded checksum strings - others more  
fundamental, such as ambiguous keyword ordering restrictions.

But, if we're not to discuss merit, that drops us to two criteria for  
registration:  documentation and prior use.  Like all the other  
conventions to date, this one appears to have been actually used in  
some large or small number of files.  The documentation seems too  
minimal and unconstraining, however, as expressed in the previous  
messages in this thread.

Rob

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