ServerDoc will start a program and check if the program is still running every five seconds and restart the program if required (if it crashed, etc.). It can also rotate servers with its internal scheduling. You may want to run a game server between 6pm and 10pm or run different game servers hourly/daily/weekly or monthly. Serverdoc can even be set up to load a different mod/patch. You could have your servers set up to run Normal DeathMatch one night, Team Fortress the next, Counterstrike the night after.