A computer system can always execute processing under the same environments not depending on the terminal device that is directly used by the user, no matter where the client used by the user is, and no matter what device is used. In the computer system, one of plural computer PCBAs that do not install a hard disk device therein is selected from the terminal device, remotely controllable environments are constituted, and data is read and written from the hard disk device which are coupled to all of the computer PCBAs over a network that is used by the user.