Abstract: Since an instruction of switching of the system operation environment or configuration such as the power save mode and power-up mode is input by the hot key operation using SMI, key data of the hot key can be instantly received by the CPU even while any type of application program is being executed, and the operation environment is changed. Further, when the system operation environment or configuration such as the power save mode and power-up mode is changed, a pop-up window indicating the present system operation environment is automatically opened on the display image plane according to the rewritten operation environment or system configuration data of the CMOS memory. Therefore, the operation mode switched by the hot key function can be instantly indicated to the user. When an event mode is set, in response to a change of a power supply status, a power supply controller set data indicating the changing of the power supply status, into a predetermined register of the computer system.

Abstract: A portable computer that includes a first ROM for storing an OS, a second ROM for storing at least one piece of existing application software, and a flat display panel for displaying at least one icon to read out the existing application software stored in the second ROM. Since the DOS and the application program are respectively stored in a DOS ROM and an application ROM, the DOS or the application can be quickly executed without install processing from floppy disks.

Abstract: When the MS-DOS is not installed from an FDD or an HDD but is installed from a built-in DOS ROM arranged in a memory space in which bank access to the computer main body can be performed, at the time the system power is turned on, a menu display processing program stored in the DOS ROM is executed by the DOS. Upon execution of the program, the arrangement of menu icons can be arbitrarily changed on the menu screen.