Periodic execution of a program

[Guy Harris]

 >Just about every man page I've seen for the at command has the following
 >in it:
 >
 >   BUGS
 >        Due to the granularity of the execution of /usr/lib/atrun,
 >        there may be bugs in scheduling things almost exactly 24
 >        hours into the future.
 >   
 >This includes SunOS, Pyramid, Vax, and a number of others.  You 
 >may run into this problem.

It's missing from the AT(1) man page on the SunOS 4.0.3 machine on which
I'm typing this.  Part of the reason for that is that SunOS 4.x uses the
S5 "cron"/"at" package, which doesn't *HAVE* "/usr/lib/atrun"; instead,
"cron" runs both "cron" and "at" jobs, rather than "/usr/lib/atrun"
being run every 15 minutes or whatever out of "crontab".