
Home Computer Cron
-------------------

Does your computer run 24 hours a day? Are you establishing uptime records
that would scare users of other OS's? If so, this program is not for you.
However, if you turn your computer off at least once a day, like the rest of
us, you might find it quite helpful. This program is a modification of Paul
Vixie's cron daemon that is intended for ``home computers'' i.e. computers
that don't run all the time. Basicly what it does in addition to standard
cron behaviour, is to remember the time it was shut down in the file
/var/lib/cron.lastrun (or something similar) then reads it back at startup
and looks whether any jobs have occured while it was down. If so, these are
scheduled and executed one every minute. The files included in this
distribution are those of the original vixie-cron3.0.1 with only minor
changes, except for hccron.c which contains the additional code. Because of
this, hc-cron can be used as a drop-in replacement of vixie cron. As long as
you don't touch your crontabs, everything will continue to work as before.
All that is required to use the additional features, is to add some flags to
the cron lines (see man pages for details).

I hacked this piece of code together because I was annoyed that standard
cron didn't run the jobs regularly on my laptop. The same problem is solved
by anacron (a program from the Debian Linux distribution); however I felt,
that adding yet another program to startup that requires you to maintain its
own configuration file was the wrong approach. So I took a deep breath,
downloaded the sources of vixie-cron (actually the patched version that is
included in RedHat5.0) and tried my best. However, I don't really feel like
my knowledge of C and programming in the UNIX environment is sufficient for
such a project (also I have a thesis to write in real life, and it isn't in
computer science). So I'd be happy if a *real* programmer could take the
code, improve it, make it portable and so on.

That being said, the program works nicely on my computer, however I don't
guarantee it will on yours. If you or your computer take any damage from
running this program (or looking at the source :), I refuse any liability.
My additions to the code are placed under the GNU General Public License
(Version 2 or later), please see the file COPYING for details.

Felix Braun <fbraun@atdot.org>
05 March 1998
