When cron won’t cut it

Our production systems at work started off like most, having cron run simple jobs at regular intervals. As the company grew, and the technology evolved however, cron started failing us. Paul Vixie, don't go in there! Our requirements started involving job restarts upon failure, jobs being dependent upon another job successfully completing, and jobs that needed to be run only when certain system parameters were met (load, disk usage, etc). Of course, the cron scripts could be modified to meet these needs, but there exist several expensive commercial solutions that accomplish the same thing and don't require the system administrators to spend all their time coding cron scripts. I looked around, and to my surprise I found no decent opensource job scheduler for unix. Does anyone know of a free and opensource unix job scheduler? I'm going to write one, if anyone is interested in helping. Let me know. To the mines with him!