Proposed 64-bit changes

Olson, Arthur David (NIH/NCI) olsona at
Mon Apr 25 15:03:38 UTC 2005

> ...or America/Los_Angeles the old file is 1017 bytes, whereas the new file
is 9107 bytes.  Why did it grow by a factor of 9?

This is just about what I'd expect. There's the data in the old format (a
factor of one) plus the data in the new format, where two considerations
	1. the transition times are 64 bits rather than 32 bits, doubling
the size.
	2. About 400 years of transitions are recorded rather than about
100, quadrupling the size.
The combination of the two consideration means that the new data takes about
8 times as much space as the old, and the total is about 9 times as much as
the old.

(Recording 400 years of data lets us extrapolate into the far future.)

> about if we modify the format so that the second copy contains only
the information that's not in the first copy?  This should help prevent

Back of the envelope, we'd end up with...
	100 years in the old format = 1x the old file size
      300 years in the new format = 6x the old file size
...leaving us with new files that were seven times the size of the old ones
(rather than nine times as is the case now)--some savings, but not as much
as we might like.
Having duplicate information in the files does minimize changes to the
existing code, and it does allow other file users to simply ignore the
old-format information.


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