A computer system having a plurality of computers connected to each other by a
computer coupling mechanism. Each computer includes a processor, memory, I/O device,
disk control mechanism, computer coupling network adapter, disk requirement processing
section connected to a system bus, and a disk connected to a disk control mechanism.
The disk requirement processing section controls the disk, in response to a processing
requirement for the disk from one of the processors of the other computers, based
on structural definition information. The structural definition information describes
a structure of the computer system. The computer system may be a loosely-coupled
computer system.