PURPOSE: To improve operability for restarting a computer system in the case of changing an operation condition by providing a file table updating means, which stores a load module name and a device configuration table name to a current file information register area, and a reloading means.

CONSTITUTION: When a reloading command is inputted, the command is received by a command receiving means 2 and a file table updating means 32. The file table updating means 32 stores the contents of the current file information register area in a file table 45 into a preceding file information register area and stores the load module name and device configuration table name, which are designated by the reloading command, into the current file information register area and a reloading means 12 is activated. After automatically executing initial setting required for restart, the reloading means 12 loads the table to the load module or device configuration, which is updated from a system disk 40, onto a main storage device 30. Thus, operability is improved.