An information processing apparatus according to the present invention stores suspension data in a non-volatile storage and performs a 0 V suspension process by which are turned off all power sources of the apparatus. An active suspension process is performed, by which are turned off power...http://www.google.de/patents/US5710931?utm_source=gb-gplus-sharePatent US5710931 - Suspension state control for information processing devices such as battery powered computers 
