DATE-OBS='31/12/99'

Rob Seaman seaman at noao.edu
Wed Jul 10 13:53:09 EDT 1996


Barry M. Schlesinger writes:

> The eight character rule stemmed from some limitations of hardware 
> and/or software.  Every once in a while I still see notes about some 
> package that has a problem with longer strings.

Eight ASCII characters also form a 64 bit "magic" number.  This can
be used to discriminate extension types, for example, by using similar
techniques to the unix "file" command (note that /etc/magic also allows
for an byte offset).  The value isn't double word aligned, unfortunately,
since it has to start in column 12.

Rob
-- 
seaman at noao.edu, http://iraf.noao.edu/~seaman
NOAO, 950 N Cherry Ave, Tucson AZ 85719, 520-318-8248
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