[fitsbits] New DUMP FITS extension

[Preben Grosbol]

On Thursday 16 August 2007 21:51, William Pence wrote:
> The question is what do we (the FITS community in general, and the
> IAUFWG in particular) do now?  Should we draft a definition document
> describing the DUMP extension (as is currently being done for the
> FOREIGN extension type)?  Do we want to go further and endorse the DUMP
> extension for use in other data sets distributed by other projects?  Or,
> would we rather discourage the use of the DUMP (or any other new
> extension type) if the data can easily be contained in an existing
> extension type? Personally, I would rather not see a proliferation of
> new extension types that are structurally identical to the existing
> IMAGE extension.

It's long time ago but to my recollection we felt, at the time, that it
was good to reserve a few extension names such as FILEMARK 
and DUMP so that they could not be used for something very
different from what their names indicate.

One may argue that DUMP and FOREIGN are very close.  Thus,
it would have been more natural that what FOREIGN now is used for
should have been made the definition of DUMP-  but that's history.
The intention for DUMP, I think, was to store a bit-stream with very
complex structure potentially with bit fields etc.  This is somewhat
different from storage of a well define foreign file format (e.g. jpeg,
png or pdf).

I agree that we should try to keep the number of extensions to
an absolute minimum.  The correct proceedure would have been
that the Solar Optical Telescope had contacted IAUFITS before
using the extension name DUMP.  Following the strict standard,
we could declare the usage of DUMP illegal as the name was
reserved and IAU FITS was not included in the discussions
of its definition.  Such an approach would be too hard.  Since
it is already in use, the only thing we can do is to work with
them to get a definition which satisfy minimum requirements
such as inclusion of date, reference to organization, application 
and version of the writing software plus definition documents.

Preben