Fcron is a scheduler. It aims at replacing Vixie Cron, so it implements most of its functionalities.
But contrary to Vixie Cron, fcron does not need your system to be up 7 days a week, 24 hours a day : it also works well with systems which are not running neither all the time nor regularly (contrary to anacrontab).
These details are provided for information only. No information here is legal advice and should not be used as such.