problems with /etc/.attwtmp on OSx 2.5

[info-pyramid at ucbvax.UUCP]

The att universe keeps its records of logins/logouts/reboots/date(I)
changes in /etc/wtmp (linked to /etc/.attwtmp).  This file is
read with "att who /etc/wtmp."

The ucb universe uses /usr/adm/wtmp (linked to /etc/.ucbwtmp) for
logins/logouts. This file is read with "ucb last."

I think that /bin/login writes to both of these files, which
makes sense since a user in either universe should be able to
see records of users in both universes.   Our .attwtmp is 2.7M
long since September, but we don't do lots of loggin in/out
here.  Anyway, if you delete it all you will lose is a record
of who has been logged in.  It will probably come back.  I guess
you could symbolically link it to /dev/null.