Does the on-disk image of an executable ever change?

[Michael ODonnell]

> Have you done straight (non-hashed) content-comparison of any of
> these files?  Are they actually gratuitously different in content,
> or are they just truncated on one system?  MD5sums are effectively
> dependant on file-size....

The files were the same size but differed in various locations (no more
than 1Kb worth but in multiple places) as reported by cmp -l, the results
of which I did not preserve - sorry.  I am now not completely certain
whether those differences were due to something benign like prelink or
from some sort of bitrot.  That would be worth knowing.

> What prompted this investigation in the first place?  You wrote
> "behaving strangely"..., but can you give some elucidation as to
> what that means?

Of three nominally identical machines (loaded from the same installation
media) that each wanted be both NFS client and NFS server to the other
two, all three could be clients but one silently refused to be a server;
no diagnostics, no messages, no outward indication of failure but the
other two machines always got "server reports permission denied".

Reinstalling the ailing system seems to have fixed it.   (?)