henry@utzoo.UUCP (Henry Spencer) (02/14/84)
Shutdown(1) and /etc/rc have been modified to cooperate in shortening
the reboot sequence after a clean shutdown. Shutdown(1) tries to
unmount the file systems; if it succeeds, it creates /clean.shutdown .
/etc/rc looks for /clean.shutdown; if it's there, /etc/rc bypasses most
of the filesystem checks. The result is that a reboot after a clean
shutdown takes only a minute or so.
The unmount stuff really ought to be in init(8) or one of its auxiliaries.
Quite apart from considerations of asymmetry, shutdown's unmount attempts
occur before the final kill-everything operation undertaken by init, with
the result that stubborn background processes may prevent unmounts. In
such a case, the shutdown really is clean but doesn't look that way to
shutdown (and hence to /etc/rc). The problem is that it's not entirely
trivial to fit init with a shutdown counterpart of /etc/rc, because init's
internal structure isn't right. I studied this briefly and decided not
to pursue it just now; I'll have another try if problems arise.
--
Henry Spencer @ U of Toronto Zoology
{allegra,ihnp4,linus,decvax}!utzoo!henry