Abstract: In a computer system including a video subsystem, a method for storing and displaying a power on graphical image, comprises the steps of: storing a compressed graphical image in a programmable read-only memory (PROM); initializing a power-on self test (POST); decompressing the compressed graphical image;loading the decompressed graphic image into a random access memory (RAM); and displaying the graphical image during the POST. Also in accordance with another aspect of the invention, a method for adding a user selected graphic image to a system ROM image, comprises the steps of: searching the Flash image file for the graphical image signature (GIS); locating the actual graphical image data with the graphical image header; reading the new graphical image data; overlaying the old graphical image data into a Flash image file; and recalculating the system ROM checksum.

Abstract: A computer system and method for operating a computer system capable of running in mutually incompatible real and protected addressing modes, in which programs written for one mode can be run in the other mode without modification. The BIOS assembles two different common data areas for the two modes, each inclusive of device block pointers, function transfer table pointers, data pointers, and function pointers. The common data area for the real mode is assembled first. To assembly the pointers for the protected mode common data area, the offset values from the real mode area ae copied directly, and then selector values are inserted whose physical addresses correspond to the segments of the corresponding pointers in the real mode area. The selector values are derived from a segment descriptor table.

Abstract: A computer system and method for operating a computer system capable of running in mutually incompatible real and protected addressing modes, in which programs written for one mode can be run in the other mode without modification. The operating system using BIOS assembles two different common data areas for the two modes, each inclusive of device block pointers, function transfer table pointers, data pointers, and function pointers. The common data area for the real mode is assembled first. To assemble the pointers for the protected mode common data area, the offset values from the real mode area are copied directly, and then selector values are inserted whose physical addresses correspond to the segments of the corresponding pointers in the real mode area. The selector values are derived from a segment descriptor table.