A sequence of operations that is performed to reset a previously running system, after an unintentional shutdown. Synonym warm start. 2. In computer operations, the restarting of equipment, after a sudden shutdown, that allows reuse of previously retained initialized input data, retained programs, and retained output queues. Note 1: A warm restart may be needed after a program failure. Note 2: A warm start or restart cannot occur if initial data, programs, and files are not retained after closedown. Synonyms hot boot, warm boot.