US 5,862,308 AGranted

Fault intercept and resolution process independent of operating system

AssigneeBull HN Information Systems Inc.

InventorsSidney L. Andress, Lowell D. McCulley

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Abstract

A fault handling process in a computer system subject to CPU design errors and functioning under an operating system (OS) having an integral fault handling module includes the steps of: setting an intercept flag when a central processor fault occurs if the fault is to be directed to a preprocessor; establishing a safestore frame which includes information identifying the type of fault and whether the intercept flag is set; and transferring control to the OS fault handling module; then in the OS fault handling module, determining whether the intercept flag is set; if the intercept flag is not set, handling the fault in the OS fault module; if the intercept flag is set, transferring control from the OS fault module to an Intercept Process written in machine language; and handling the fault in the Intercept Process. This renders the resolution of faults due to correctable CPU design errors independent of the OS employed at a given installation and customizable to a given system without the need to revise the OS fault modules for each OS. As each such design error is worked out (e.g., by installing a substitute integrated circuit in which the error has been corrected), the Intercept Process (and CPU firmware) can be modified to remove monitoring and handling for faults due to the corrected error.

Claims3

Dependent claims

In a computer system functioning under an operating system including a fault handling module, a process for handling a central processor fault comprising the steps of:

A) employing, when a central processor fault occurs during an operation, a modifiable central processor firmware, which firmware is configured to recognize a central processor fault which is due to a known hardware design error and which firmware is reconfigured after the known hardware design error has been corrected to eliminate monitoring for faults due to the known hardware design error, for:
i. sensing said central processor fault;
ii. selectively setting, while establishing a safestore frame, an intercept flag if the fault is to be directed to a preprocessor;
iii. establishing said safestore frame which includes information identifying the type of fault and whether the intercept flag is set;
and
iv. transferring control to the operating system fault handling module;
B) in the operating system fault handling module, determining whether the intercept flag is set;
C) if the intercept flag is not set, handling the fault in the operating system fault handling module and going to step F);
D) if the intercept flag is set, transferring control from the operating system fault handling module to an intercept process written in machine language;
E) handling the fault in the intercept process;
and
F) retrying the operation which caused the fault in the central processor.

9 more elements

Dependencies are inferred from the claim text.