Patent 7340638 was granted and assigned to Microsoft on March, 2008 by the United States Patent and Trademark Office.
An improved operating system method that, in addition to the primary operating system, stores one or more alternate or recovery operating systems. The system monitors the operation of the present operating system and accesses the alternate or recovery operating system based on a fail-over algorithm when a fault condition is detected. The alternate or recovery operating systems are periodically updated.