(From Anachronism + cron) A daemon that runs as a supplement to Cron. The difference between Anacron and Cron is that Anacron doesn't assume the machine is always up; it executes commands that were supposed to be run during the downtime when machine comes up again.
Great program to have in Linux if you have a habit of keeping the machine off during the night...
Anacron was written by Christian Schwartz and it was later rewritten by Itai Tzur.