I'm trying to come up with an efficient way to see if a non-VSAM data set
has been changed.
Flipping the DS1IND08 bit is not an option, nor can I install SMF hooks,
etc in the OS.
The problem, of course, is that DSCBs don't have "last update timestamps".
My initial whack at this would be to use a two-part hash:
part 1: a shortened SHA1-hash of the format-1/8 DSCB
part 2: a full SHA-1 hash of all of the data
The goal is to calculate something when I read an entire data set and keep
it, and then later I can use this to later know if I need to read the data
again.
So: a part 1 match is non-informative (the data set could still have
changed, although not likely)
a part 1 mismatch would tell me that most probably the data set has
changed (or just moved?). I would then have to read the entire data set to
determine if it really has changed.
Thoughts?
Kirk Wolf
Dovetailed Technologies
http://dovetail.com
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