Following is the claim for this invention:-

1. In this invention we have a power supply circuit consisting of a watchdog timer which is an electronic timer to detect and recover from computer malfunctions. During normal operation the power supply circuit for the rack regularly resets the watchdog timer to prevent it from elapsing or timing out. If due to hardware fault or power supply failure, the power supply circuit fails to reset the watchdog timer, then the watchdog timer will elapse and generate a timeout signal. The timeout signal is used to switch on the standby or backup power supply for the rack. The above novel technique of providing a backup power supply for the rack is the claim for this invention.