Mechanism to improve fault isolation and diagnosis in computers

Abstract

A system and method for improving the isolation and diagnosis of hardware faults in a computing system wherein means are provided for indicating whether unusable data has previously triggered diagnosis of the hardware fault that caused the data to be unusable. If diagnosis has not been performed, the flag is not set. If diagnosis has already been performed, the flag is set. One embodiment comprises an interface which is used to convey data from one subsystem to another. When the interface receives data from the first subsystem, the data is examined to determine whether it contains an uncorrectable error (including missing data.) If the data contains an uncorrectable error, the interface examines the flag corresponding to the data to determine whether hardware fault diagnosis has already been initiated. If diagnosis has already been initiated, the data is passed to the second subsystem without initiating further diagnosis. If diagnosis has not been initiated, the interface initiates diagnosis and sets the flag to indicate that diagnosis has already been initiated. The data and corresponding flag are then passed to the second subsystem. If the data contains an uncorrectable error, data error handling procedures will be performed by the subsystem that requested the data, regardless of the value of the corresponding flag.