Trashed /etc/utmp under SysVr3.1

[Tom Yager]

While working with a new system, I managed to crash it just after completing
a full backup. I reinstalled the base system, then restored my full backup
over the top of it. Following the restore, utilities that use /etc/utmp
(init, login, who...) either died without comment or bitched about not
being able to write it.

I've seen discussion on this here before, but I was never alert enough to
cache the answer away for future reference. I know that utmp and wtmp are
supposed to be tops on the list of files NOT to back up, but this was just
a safety net--good thing I did it, too!

I was even patient enough to load the complete UNIX in, then restore only
/bin/* and /usr/* from my backup tape. As soon as the tape started coming
in, utmp stopped working. What's going on?

If the magic for rebuilding utmp is documented somewhere, please point it
out to me. For penance in my failure to RTFM, I'll lash myself 6250 times
with a length of magnetic tape.

For the curious, this question was raised on an Opus 8000-series system
(Motorola 88000 processor) running System V, release 3.1.

This probably isn't of broad enough interest to post the response. Please
e-mail any answers. I'll save them this time, and pass them on to any who
request.

Thanks.
(ty)

-- 
+--Tom Yager, Technical Editor, BYTE magazine------------------------------+
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