Abstract: The CPU operates at the highest speed in start processing of an operating system. When a power-saving driver receives a start completion message from the operating system, the power-saving driver waits for a predetermined period until user operation to a computer system is enabled, and then sets the processing speed of the CPU to a user-designated speed. When the power-saving driver receives from the OS an OS termination start message representing the start of shutdown processing, the power-saving driver cancels setting of the user-designated speed, and returns the CPU to, e.g., the highest speed. Hence, start processing/shutdown processing can be executed at a high speed regardless of the set value of the user-designated speed.

Abstract: In an information processor having a power control function for controlling the power of devices that make up a system, a battery drive time during which the information processor is to be battery-powered is specified by a user. Power control parameters for the devices are computed on the basis of the specified battery drive time. Each of the computed power control parameters is then set up on a corresponding respective one of the devices.

Abstract: A sound controller comprises circuitry that performs a variety of sound functions. The circuitry is only powered when required by an application program. A power-saving driver receives a message issued from an operating system. When the message means indicates that a sound function is starting to be used, the power-saving driver turns on the power supply of a sound controller and then hands over the message to the sound device driver. In contrast, when the message indicates that the use of the sound function is ending, the power-saving driver first hands over the message to the sound driver, thereby causing the sound driver to execute an end process. After a predetermined time has elapsed since the power-saving driver handed over the message, it turns off the power supply of the sound controller.