Patent ID: 8671270

Claim:
A computer system including: a computer including a central processing unit (CPU), a memory and a physical input/output (I/O) device; and an input/output (I/O) apparatus connected to the physical I/O device, wherein the memory stores both an extended firmware which drives the physical I/O device, and a bootstrap program which has been loaded by the extended firmware and used in initial operation of the computer system, the extended firmware includes a basic input/output system (BIOS) emulator and a plurality of device drivers, and overwrites a BIOS emulator vector on an interruption (INT) vector for handling a BIOS call included in the bootstrap program, and when determining driving of the physical I/O device, in response to an interruption instruction corresponding to the INT vector overwritten with the BIOS emulator vector executed by the bootstrap program, the BIOS emulator takes over a BIOS process according to the BIOS emulator vector and performs a BIOS switching check to decide a BIOS switching on a basis of whether the physical I/O device mounts a BIOS or not, wherein, if the BIOS emulator determines as a result of the BIOS switching check that the physical I/O device mounts a BIOS, the BIOS emulator hands over the BIOS process to the BIOS to drive the physical I/O device supported by the BIOS, and if the BIOS emulator determines as a result of the BIOS switching check that the physical I/O device does not mount the BIOS, the BIOS emulator emulates the BIOS to call the extended firmware to drive the physical I/O device supported by the extended firmware.