war story: parallel(1) command

[James Knott]

D. Hugh Redelmeier wrote:
> MD5 hashes are quite reasonably distributed over the 128-bit space. You'd 
> need something like 2^64 things for the birthday paradox to fire.

Okay.  You have 128 bit hash.  That's 2^128 possible combinations.  Now
take a bunch of 1 KB (2^10) files.  Those are 2^13 bits and 2^(2^13)
combinations.  That means for any given hash, you could have an
extremely large number¹ of different files that size that could have the
same hash.  Granted, duplicate hashes are extremely rare, but you can
never claim they're impossible.

1. The KDE calculator can't handle a number that large
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