From: bob@dalek.mwc.com (Bob Hemedinger)
Newsgroups: comp.os.coherent
Subject: Forwarded mail...
Date: 3 Sep 92 20:15:57 GMT
Reply-To: "Coherent operating system" <COHERENT@indycms.bitnet>

Forwarded message:
From dnieper!vlad  Wed Sep  2 18:17:26 1992 remote from mwc
Message-Id: <9209021315.AA485.V1.4@dnieper.mwc.com>
Date: 2 Sep 92 13:15:43
From: vlad@dnieper.mwc.com (Vladimir Smelyansky)
To: bob

Subject: Re: Coh 4.0.1 crontab problems

Hello Roger,

> > > : I successfully upgraded to Coherent 4.0.1!!
> > > :
> > > : Now I would like to convert my old /usr/lib/crontab to use the new
> > > : /usr/spool/cron/crontabs/.., but whenever I move the items for root
> > > : uucp to execute from the old /usr/lib/crontab to the new directory,
> > > : they stop working.
> > > :
> > > : This has gotten to be a pain since I have upgraded GNEWS and compiled
> > > : it under 4.0.1 to be 386 executables, so the old 'besomeone' of 286
> > > : vintage does not exist in the new crontab structure.
> > > [ deleted stuff looks fine ]
> >
> > Did you create a cron.allow file which lists user 'news'?
> >
>
> I have since done some experimentation.  Using the root and
> uucp crontabs furnished with Coherent 4.0.1.  I still get
> spawning of cron processes.
>
> ps -a yields:
>
>  .
>  .
>  ----- 46 cron
>  ----- 47 cron
>  ----- 48 cron
>    .
>    .
>    .
>  ----- 411 cron
>  ----- 412 cron
>
> This seem to muliply at about 5 minute intervals with each cron
> spawning at least 8 other cron processes.
>

"ps -a" does not give enough information to trace a problem. Can you
run "ps -alxd" and mail whole output to me? The crontables could be informative
too.

For now, let me explain why you may see a "lot of crons".
(Sorry for bad English)

From the beginning cron runs as root, but job should be fired with
permissions set to owner of the table. When a proccess changes
uid to a regular uid it cannot change it back to the superuser.
The way around it is to fork a child, parent stays the superuser and
looks for the next tasks when child changes uid to the owner of the table
id and fires a process.

The second reason is next: if somebody asks to do a few
jobs in the same time the best approach is to start all of them and alllow
to a system scheduler performs its job.

The one more "problem" with SV cron is that cron waits for all children
to be done and check an exit status for each of them. If child fails,
cron may notify an owner of a table about a failure (this option can be
disabled).

So, SV cron is a powerfull tool. It was under beta test ~0.5 year. But,
I would not garantee that all bugs were terminated.

In COHERENT 3.* compatibility mode the first and last problems go away.
It behaves as old friend UNIX V7 cron.

By, Vlad.

--
vlad@mwc.com	e-mail		I cannot find word "pizza" in Russian-English
708-291-6700	voice		Dictionary that has ~25000 words.
708-291-6750	fax		Any idea why?





vlad@mwc.com	e-mail		"We do not completely love those at whom
708-291-6700	voice		we cannot smile."
708-291-6750	fax			Andre Malraux, 	The Art of Living.


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Newsgroups: comp.os.coherent
Subject: Re: Copying files to floppy disks