[wfc] Re: CHECKSUM Proposal

[Rob Seaman]

> I suspect that around 1-2 pages of introduction and practical usage
> hints would be enough to fill it out.

I am a little hazy on how much introduction is needed for the concept of
a checksum.  I would have thought the utility of such would be obvious to
the FITS community.  The key concept here is not that data checksums are
a good thing - it's that a method is provided to embed those checksums
within a FITS HDU object, rather than having to rely on some separate
ascii file on an FTP server, for instance.

I like the suggestion of offering practical hints - but this sounds like
something to include in a user's guide, not in the standard itself.

> I went back to the NOST FITS Glossary and was still confused about
> the meaning of HDU - one sentence to clarify the question I asked
> would avoid the whole issue.

Sounds reasonable, but I must say I have always thought the term HDU
to be well defined - as it must be for such a fundamental FITS concept.
Which begs the question - are other FITS terms widely misunderstood?

> I am not opposed to the proposal to have checksums included.  It
> seems like a good idea, although we get very few if any reports of
> failure these days on the 40+ Megabyte AIPS tar ball.

Surely there are many orders of magnitude more data files exchanged by
our community on a given day than software distributions.  I would be
surprised if any of the major software projects did NOT provide checksums
as a matter of course, but if we are receiving few reports of transmission
failures - might that not also be the result of simply not looking for any?

> Don's question about how often this is checked and found to prevent
> error is relevant to those of us who would have to go to a lot of work
> (and cost to the user) to implement the concept.

The proposal does not require that any particular project implement
checksums - we are simply adding another tool to the FITS toolkit.

> What I am opposed to is the current presentation of the proposal.  I
> have spent more than a year FTE on the WCS proposals to make them not
> only correct but also fully readable and professional in appearance
> as well as content.  And the committees never take them up despite
> statements that they will.  Given that, why should I now vote for
> some other proposal that does not meet the professional standards
> for a standards proposal?

The FITS community could likely have a worthwhile discussion about the
effort spent on the presentation of proposals versus their content.  There
is obviously no connection, however, between the omnibus WCS document and
our tiny checksum proposal.  I'm surprised to see them mentioned together.

Rob Seaman