Abstract: A computer system, which shifts a mode to a power saving mode when there is no user input at a keyboard for a predetermined time period, employs a circuit for detecting writing to a video memory, and a power management program for managing power in corporation with the circuit. When the writing to a video memory is performed, a shift to the power saving mode is inhibited, even though there is no input at the keyboard during the predetermined time period.

Abstract: A two-line multi-station bus system has a clock wire and a data wire and supports selective slave station addressing by a prevalent master station for thereupon eliciting a bitwise clocked data transfer between the clocking master station and an addressed and clocked slave station. Moreover, the system supports analog signal transfer in that the prevalent master station has a holding member for while eliciting the analog signal from the actual addressed slave station holding said clocking through carrying the clock wire at a predetermined binary value. The analog signal is received until changeover of the clock wire to a binary value other than the predetermined binary value a particular version the analog signal is pulse width modulated in combination with associate delimiting signals on the clock wire sent by the transmitter station that is not necessarily the master station.

Abstract: A method of managing the power consumed by a hard disk drive in a portable computer. The first step consists of measuring the work load placed on the hard disk drive by a particular computer, a particular application and a particular user. The next step is to determine the average power consumed in the disk drive in the active state and in a lower power state for a series of wait times. The next step is to determine the total average power consumed by the disk drive for both states for the series of wait times. The next step is to determine the wait time at which the total average power consumed by the disk drive in minimum. The final step is to set the wait time at which the disk drive operates to the previously determined minimum wait time.