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From: johngm@dhw68k.cts.com (John Miller)
Newsgroups: comp.unix.xenix
Subject: Re: Cron Problems
Summary: Cron has a short memory
Message-ID: <24919@dhw68k.cts.com>
Date: 18 Jul 89 18:35:42 GMT
References: <7613@charlie.OZ>
Organization: Wolfskill & Dowling residence; Anaheim, CA (USA)
Lines: 22

In article <7613@charlie.OZ>, vortex@charlie.OZ (Mark Gregson) writes:
> 
> 	I have a small problem with cron on a Xenix 286 system running
> 	system V version 2.2.1. 
> 	At present I have a job in the file /usr/spool/cron/crontabs/root
> 	that has this entry 0 23 * * * /usr/markg/news.
> 	The idea behind this entry is to have the program news run at
> 	2300 hours or 11pm, which does happen. However, this program 
> 	also executes at 500 hours or 5am?? Which it is not supposed to
> 	do. Can anyone please tell me why this type of error would 
> 	possibly occur??

This happened to me also, but I found a fix and SCO confirmed it.   When
your version of cron was written the timer variable was assigned as a short
int.   Consequently when a certain amount of time passes between cron jobs
the timer variable will roll over.  When this happens cron executes your 
job again.  The solution is to run a do nothing job about 12 hours before
your job.  I run mine at 1:30PM.  Just run something like /bin/true.

John Miller

johngm@dhw68k.com