Appeal No. 97-4062 Page 2
Application No. 08/590,049
BACKGROUND
The invention at issue in this appeal relates to
diagnostics for a computer. In prior computers, a central
processing unit (CPU) retrieved diagnostic code stored in a
basic input-output system (BIOS) read-only memory (ROM)
attached to the CPU by an input/output (I/O) bus. A fault in
the BIOS ROM or the I/O bus could prevent the CPU from
retrieving the diagnostic code.
The invention is an interception and substitution circuit
for a computer. The circuit intercepts a request from a CPU
for diagnostic code stored in a BIOS ROM and sends the CPU
substitute diagnostic code stored in local ROMs. When
executed by the CPU, the substitute code determines whether
the CPU and its host bus are functioning properly.
Accordingly, diagnostic testing can be done on the computer
even when a fault prevents the CPU from retrieving the code in
the BIOS ROM.
Page: Previous 1 2 3 4 5 6 7 8 9 10 Next
Last modified: November 3, 2007