Patent ID: 7434042

Claim:
An apparatus where an operating system, read out from a selected device of a multiplexed plurality of devices containing respective operating systems, is started up for starting up a data processing system, comprising: a storing unit which stores environment data setting a boot from said plurality of devices, where said environment data includes: first variable data including device setting data designating boot candidates for said plurality of devices, second variable data including index data setting a booting order of said boot candidates set by said device setting data, and third variable data in which whether said multiplexing of the plurality of devices is valid or not valid is set; a boot control unit which decides on a boot device according to data set by said first variable data, said second variable data and said third variable data included in said environment data, and starts up said respective operating system stored in said boot device; and a control unit which controls setting said environment data of said plurality of devices, setting valid for multiplexing in said third variable data when a first boot candidate included in said device setting data is accessed according to said booting order defined by said second variable data, changing said booting order of said boot candidates in said index data included in said second variable data when an abnormality is detected in said boot device, and clearing said index data of said second variable data to an initial value when booting is successful, said boot control unit switching said accessed boot device to another boot device according to a changed booting order of said index data and controlling starting up of said respective operating system stored in said another boot device.