Abstract: The present invention provides a digital computer system executing a scheduled operation and method thereof including: a main system having a central processing unit for processing an interrupt processing routine; a bus which transmits information to system elements by connecting the main system and the system elements; a system memory which is connected to the bus and stores system information such as hibernation information; a power supply which supplies an external power to a computer system and supplies power to the computer system when the external power is turned off; a wake-up source which senses, receives and outputs an external change; a power control connected to the wake-up source, the power supply and the bus, controls the computer system for a hibernation function and receives the external change signal from the wake-up source in order that the computer system can execute the scheduled operation; and a storing device which is connected to the bus and stores data such as information of the system