Computer apparatus and external storage device which can be used by

Abstract

A computer apparatus such as a lap-top type personal computer or the like having a disk device as an external storage device executes a power save process to reduce an electric power consumption on the basis of a power save designation command from an OS. The computer apparatus comprises a computer main body and an external storage device. The computer main body has a power source kind detecting section for generating a power source mode signal indicative of an external power source mode when the use of an external power source is detected and also indicative of an internal power source mode when the use of an internal power source by a battery provided in the apparatus is detected. A power save processing section is provided for the external storage device. When a power save command is received from the computer main body, a check is made to see if the power mode is the external power source mode or the internal power source mode on the basis of the power source mode signal sent from the computer main body. When the external power source mode is discriminated, a power save process to shut off the power supply to a predetermined circuit section is inhibited even if the power save command exists. When the internal power source mode is discriminated, the power save process is executed in accordance with the power save command.