Patent ID: 7757112

Claim:
A computer medium storing logic comprising: receiving a boot interrupt signal to interrupt a boot loader invoking a current master boot record (MBR); in response to the boot interrupt signal, determining whether a data structure listing plural backed-up MBRs is valid; in response to a determination that the data structure is valid, backing up the current MBR and furthermore overwriting a current master boot record (MBR) with a service MBR; using the service MBR, booting a service operating system; and replacing the service MBR with a previously backed-up MBR, wherein the current MBR is overwritten with the service MBR only if the service MBR is first determined to be valid; in response to a determination that the data structure is not valid, testing at least one backed-up MBR by accessing a partition using a partition table of the backed-up MBR; determining whether the partition has a valid partition header partition boot record (PBR) to ensure that the partition is the partition indicated in the partition table; comparing data found in the partition to data in a most recent backup of the partition, and if at least the data found in the partition and the data in the most recent backup of the partition agree, replacing the current MBR with the backed-up MBR.