APPARATUS AND METHOD FOR DECREASING THE MEMORY REQUIREMENTS FOR BIOS IN A PERSONAL COMPUTER SYSTEM

摘要

ABSTRACTAn apparatus and method for decreasing the memoryrequirements of BIOS in a personal computer systemincludes storing a first portion of BIOS in memory and asecond portion on a direct storage access device. Thepersonal computer system comprises a system processor, arandom access main memory, a read only memory, and atleast one direct access storage device. The read onlymemory includes the first portion of BIOS and datarepresenting the type of system processor and systemplanar I/O configuration. The first portion of BIOS onlyincludes routines for initializing the system and thedirect access storage device to read in a master bootrecord into the system from the direct access storagedevice. The master boot record includes a data segmentand an executable code segment. The data segmentincludes data representing system hardware and a systemconfiguration which is supported by the master bootrecord. The first BIOS portion confirms the master bootrecord is compatible with the system hardware byverifying that the data from the data segment of themaster boot record agrees with the system processor,system planar, and planar I/O configuration. If themaster boot record is compatible with the systemhardware, the first BIOS portion vectors the systemprocessor to execute the executable code segment of themaster boot record. The executable code segment confirmsthat the system configuration has not changed and loadsin the remaining BIOS portion from the direct accessstorage device into random access memory superseding thefirst BIOS portion. The executable code segment thenverifies the authenticity of the remaining BIOS portionand vectors the system processor to begin executing theremaining BIOS now in random access memory. Theremaining BIOS in main memory includes reusable routinesfor operating the personal computer system in a normalmanner.