Patent ID: 7383431

Claim:
A control device comprising: a CPU; a RAM; a nonvolatile memory; wherein said nonvolatile memory comprises; a cold boot sector for storing cold boot data, at least a first and second boot sector for storing other boot data including boot update evaluation data with each boot sector having a program process stored therein independent of the program process stored in the other boot sectors for rewriting data in boot sectors other than itself; a main memory portion having one or more main sectors for storing main data; a boot data evaluation unit including an evaluation data operator for calculating a count value corresponding to the size of the boot update evaluation data stored in at least each of the first and second boot sectors respectively, a program comparator for distinguishing which of the boot sectors has a higher count value and a program selector for selecting a program process from the boot sector having the highest count value for rewriting data in boot sectors other than the boot sector with the highest count value; and a rewrite unit responsive to the program process selected by the program selector in the boot data evaluation unit for rewriting data stored in the main memory portion and in a boot sector other than the boot sector which has been recognized as having the highest count value wherein the first and second boot sectors do not include main data.