Re: Full duplex using 2 sound cards.

Keith Rohrer (
Tue, 28 Jan 1997 19:33:56 -0600 (CST)

[while recording audio]
> For reasons unknown I absolutely *must* kill (vixie) crond, even though
> there are no cron jobs to run and all it's doing is calling stat()
> on a FIFO every minute;
As a possibly related problem, a csh script which I thought ought to be
running entirely in RAM was performing hideously, with the disks constantly
in motion; I tracked it down to the following line (in a loop):
set diffs = "`diff $args |head`"
This line seemed (assumging $args evaluated to a pair of valid filenames)
to force and wait for some disk action(s). I isolated the problem down
to something of the form:
echo `cat /dev/null |cat`
under csh or tcsh; without the backquotes or without piping, it behaves
properly (also under /bin/sh), but the combination seems to force some
synchronous disk event(s) each and every time they are run. I don't
have tcsh source handy, but if it's written in a non-buggy fashion I
expect the problem is similar to the crond which "only" stats a FIFO.