Subject: Re: syntax ideas solicited
To: Perry E. Metzger <perry@wasabisystems.com>
From: Jarkko Hietaniemi <jhi@iki.fi>
List: tech-userlevel
Date: 12/25/2001 01:32:48
On Mon, Dec 24, 2001 at 06:22:05PM -0500, Perry E. Metzger wrote:
> 
> Dave <dgriffi@cs.csubak.edu> writes:
> > > Any ideas on an appropriate character, or alternate syntaxes, or ideas
> > > on prior art, or just plain ideas?
> > 
> > How about modifying the system cron scripts to prevent find(1) from taking
> > a scenic tour of the filesystems if a job was missed?
> 
> Because the problem is a more general one, IMHO, in dealing with cron
> and sleeping machines.

One problem is that there is in cron no way to differentiate between
"run this if you can, otherwise never mind" and "run this as soon as
you can (after so and so), no matter what".  In other words, forget or
delay.  In yet another words, to make distinctions like that more
attributes are needed, which may require a richer batch/queueing
system than cron may be needed.  For example in the "delay" option
one may want (at least) two different semantics: delay at most one
instance (which might be the case for, say, fastfind/locate database
updates), or queue even more instances.  (Of course one can encode all
this fancy logic into the scripts/applications; and in some cases that
may be the right choice, but in the general case it would be nice for
the batch system to take care of all that.)

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