Patent ID: 8527983

Claim:
An operating system (OS) installation method for a computer system including a system device having a plurality of host bus adaptors and an input/output (I/O) device unit having a plurality of disk units, the system device and the I/O device unit being connected to each other through the host bus adaptors by redundant connection paths, the OS installation method comprising: the host bus adaptor driver: reading the OS start information included in each of the host bus adaptors, determining only one host bus adaptor and only one connection path for installing the operating system based on the OS start information that has been read, by determining that the host bus adaptor with the flag indicating a valid state is the one host bus adaptor for receiving installation of the operating system, wherein in a case where flags of a plurality of the host bus adaptors indicate the valid state, determining the one host bus adaptor for use in installation of the operating system, based on a value of a peripheral component interconnect (PCI) number of each host bus adaptor, by determining that the host bus adaptor having a smallest value of the PCI number is the select one host bus adaptor for use in installation of the operating system, and making the installer use the determined host bus adaptor and the connection path and to not use any other host bus adaptor of the plurality of the host bus adaptors and any other connection path of the redundant connection paths, wherein the computer system includes: an installer for installing the operating system in one disk unit of the I/O device unit, and a host bus adaptor driver for controlling the plurality of the host bus adaptors, wherein each host bus adaptor includes nonvolatile memories having OS start information to register connection information for starting the operating system, and wherein the OS start information includes a flag for controlling whether the host bus adaptor is to be used or not for starting the operating system.