[fitsbits] start of Public Comment Period on the CHECKSUM convention

[THIERRY FORVEILLE]

> A second issue arises with:
> 
> 	"It is recommended that the current date and time be written into the
> 	comment field of both keywords to document when the checksum was computed
> 	(or more precisely, the time that the checksum computation process was
> 	started).”
> 
> The problem here is that one might want to reproduce a verbatim file at a
> later date and the timestamp makes this impossible since the checksum will
> differ precisely because of the timestamp.  For instance, one might (one
> has, in fact) generate a large number of files to ingest into one copy of an
> archive in one location, and regenerate the same files to ingest into a
> second copy.  Due to the large amount of data it is less expensive to
> duplicate the processing compared to copying the data remotely.  The
> timestamp should be optional.
>
I'd go one step farther and say that it should be discouraged, as the con
which you mention is significant and I cannot see any pros to offset it.