International Business Machines Corporation

Scott G Kinnear

Richard Alan Dayan

Richard Bealkowski

John W Blackledge, Jr

Robert Sachsenmaier

Kevin M Zyvoloski

Matthew S Palka, Jr

Doyle S Cronk

George D Kovach

Donald D Williams

Guy G Sotomayor, Jr

Jeffrey Isaac Krantz

Gary A Vaiskauckas

David Joseph Doria

Robert B Liverman

Jay H Neer

Andrew B McNeill

James Franklin Macon, Jr

Jerry D Dixon

Douglas R Geisler

Edward I Wachtel

William H Schwartz

An apparatus and method for loading BIOS from a diskette drive into a personal computer system normally connected to a hardfile, such as a fixed disk. The personal computer system further includes a system processor, a random access main memory, a read only memory and a switching means. The switching means generates a signal to indicate a mode for whether BIOS loads from either diskette or disk. In a priority mode, BIOS loads immediately from diskette. In a recovery mode, BIOS loads from diskette after testing the disk subsystem.

Apparatus and method for loading BIOS from a diskette in a personal

An apparatus for loading BIOS stored on a direct access storage device in a personal computer system, the system comprising direct access storage device, and a processor card removably mounted to a planar board. The processor card comprises a system processor and ROM memory, while the planar board includes a main memory. A master boot record is stored on the direct access storage device. The master boot record contains a data segment and an executable code segment, the data segment representing the hardware configuration of the personal computer system. A first portion of BIOS included in the ROM memory initializes the system and causes loading of the master boot record into main memory. This first portion of BIOS further compares the hardware configuration data of the master boot record with the hardware configuration data in the ROM memory to verify compatibility with the system processor. Once compatibility of the master boot record with the system processor is verified, the first portion of BIOS transfers control to an executable code segment of the master boot record to effect loading of the remaining portion of BIOS into main memory, and the first portion of BIOS is discarded.

Bios load for a personal computer system having a removable processor

An apparatus and method for loading BIOS stored on a direct access storage device into a personal computer system. The personal computer system comprises a system processor, a system planar, a random access main memory, a read only memory, and at least one direct access storage device. The first portion of BIOS initializes the system and the direct access storage device to read in a master boot record into the system from the direct access storage device. The master boot record includes a data segment and an executable code segment. The first BIOS portion vectors the system processor to execute the executable code segment of the master boot record. The executable code segment loads in the remaining BIOS portion from the direct access storage device into random access memory.

Initial BIOS load for a personal computer system

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.

Computer system having mode independent addressing

An apparatus and method for decreasing the memory requirements of BIOS in a personal computer system includes storing a first portion of BIOS in memory and a second portion on a direct storage access device. The personal computer system comprises a system processor, a random access main memory, a read only memory, and at least one direct access storage device. The first portion of BIOS only includes routines for initializing the system and the direct access storage device to read in a master boot record into the system from the direct access storage device. The master boot record includes a data segment and an executable code segment. The first BIOS portion vectors the system processor to execute the executable code segment of the master boot record. The executable code segment loads in the remaining BIOS portion from the direct access storage device into random access memory superseding the first BIOS portion.

Apparatus and method for decreasing the memory requirements for BIOS in

A data processing system has a microprocessor, a memory system and a plurality of system devices the operation of which is controlled by BIOS routines. The BIOS routines are accessed through protected entry points. When an application program attempts to access one of the routines by using a hard coded instruction for jumping to such entry point, a BIOS signaling routine is executed which provides a signal to an operating system allowing the operating system to control the access without being bypassed.

Signaling attempted transfer to protected entry point bios routine

An apparatus and method for protecting BIOS stored on a direct access storage device into a personnal computer system. The personal computer system comprises a system processor, a system planar, a random access main memory, a read only memory, a protection means and at least one direct access storage device. The read only memory includes a first portion of BIOS and data representing the type of system processor and system planar I/O configuration. The first portion of BIOS initializes the system and the direct access storage device, and resets the protection means in order to read in a master boot record into the random access memory from a protectable partition on the direct access storage device.

Apparatus and method for preventing unauthorized access to BIOS in a

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.

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Boca Raton, FL, United States of America

Scott G Kinnear