PURPOSE: To secure a prefix area and, simultaneously, prevent an access space from impossibleness of organization because of discontinuity of a floating space even if a storage device is in the workable condition by automatically setting a floating address corresponding to the condition of a storage unit, then securing a prefix area.
CONSTITUTION: A computer system consists of a CPU11 and a storage devices 12 and 13, and the devices 12 and 13 are provided with plural number of storage devices U1WUn and floating address registers R1WRn to set a floating address. These devices and the CPU11 are connected by a signal line 14. On the other hand, the devices 12 and 13 are provided with an operation check circuit 21 that checks for normal working through investigating the steady state of the power supply for the storage device itself, the state of trouble on each storage unit U1 and Un, etc., and its state signal is input to the floating address set circuit 20 mounted on the CPU11 through the signal line 14. Then, the floating address from the CPU11 are set to registers R1WRn by the floating address set circuit 22.
AKAGI MASANOBU
YAMAGA MITSUHIRO
TSUNODA HARUHIKO
NIPPON ELECTRIC CO
HITACHI LTD
FUJITSU LTD