CRON runs things twice

[Keith Brinck]

in article <362 at trux.UUCP>, car at trux.UUCP (Chris Rende) says:
> Xref: bain3 comp.sys.pyramid:582 comp.bugs.sys5:855
> 
> (Nixdorf Targon M35/50 TOS 3.2 --> Pyramid 9810 OSx 4.0)
> 
> On rare occaisions ATTCRON is running things twice apparently because it
> does things early. (System V Release 2 CRON)
> 
> [Stuff deleted ....]
> 
> Has anyone else observed this behaviour?

We sure have - on the same configuration with the same version
of OSx.  Its not so rare either about once every 1-2 months in
our case.

> Is it a known bug?

I have spoken to Pyramid Australia about it and they say its a
known bug in the AT&T system.  They don't know when it will be
fixed (although its rumoured to be fixed in version 5).

> Is there a fix?

We use a lock file system which catches the bug most of the
time.  Fairly recently we had an occurence which was not
caught by the lock file and as a result screwed up a
significant Sybase database.  It took us some time to rebuild
said base.

What has always amazed me about this bug is the fact that
no-one else appeared to be particularly worried about it,
including the people at Pyramid in Sydney.  Given the rate of
the incidence of the bug at our site I would guess that there
is a cron job firing of twice somewhere in the world every
hour of the day (or more) and that someone would have been
hurt by it !!

Pyramid's lack of enthusiasm in pursuing a fix for this bug
shows up one of the disadvantages of using unix - one is not
dealing directly with the originator of the os and its
difficult to get things done as a result.

---------------

I've posted this for someone else - please direct any email
replies to barry at bain3.bain.oz (Barry Allebone)