[iaufwg] Final FITS review comments

[Doug Tody]

Hi Bill -

I read through this summary and agree with your responses.

> 16.  from Mark Calabretta:
> >The new Standard should note any inconsistencies in syntax
> >between previous versions of the Standard, either as an
> >appendix or as footnotes throughout the document.
> 
> I am unsure how to respond to this suggestion.  No one seems to know of
> any specific cases of changed syntax that should be documented, and no
> one has volunteered to take on the task of searching through the
> documents to look for any such cases. I can't gauge how the FWG as a
> whole feels about this issue because there has been so little discussion
> so far.  A couple people (Allen and Shaw) have seemed to question
> whether the Standard is in fact the best place for this type of
> information.  Perhaps it would be more appropriate to put this in a
> separate FITS Implementor's Guide along with other practical guidelines.
> 
> I would like to hear how other members feel about this issue.  Is this
> issue important enough that it must be addressed immediately?  What
> is the scope of changes that should be documented, i.e., would we only
> include any changes that have occurred between versions 1.0 of the
> Standard and the current draft version 3.0, or are we also talking about
> any changes with respect to the original FITS Papers?  Is anyone willing
> to take on this task of making a detailed comparison of the different
> versions to look for changes?  Personally, I would have to say I don't
> really see the urgency in addressing this issue to cause a delay in
> voting on the new standard. But I would like to hear what others think.

I don't think this is urgent, and off hand cannot think of syntax
changes although there have been other kinds of changes to FITS
over the years.  A more general suggestion might be to have a
revisions summary.  If we have different versions of a standard then
it is always useful to note significant changes or additions in each
successive version of the standard.  However, to some extent we have
already done that, e.g., when the most recent document was put out
for review there was a written summary of the important changes.
The first thing we should do is preserve such information and make
it available along with the actual specification.

While we are on the subject of versions, it is unfortunate that we
have gotten into calling the versions of the standard "FITS V1",
"FITS V2", "FITS V3" etc.  The usual practice is to reserve full
version numbers for major changes to the standard.  Since thus far
FITS has been very careful about backwards compatibility, with no real
versioning, it would have been more appropriate to be at about FITS
V1.3 or V1.4 at this stage.  Then if we really do come out with a FITS
V2 (e.g., with major changes to the FITS header and keyword model)
it would be evident from the version number of the specification.
I am not seriously suggesting we change our approach at this point
since the current practice in FITS is well established, but merely
want to register the comment in case we really do have a significant
change to FITS in the future.

	- Doug