Patent ID: 8516310

Claim:
An information processing device equipped with a write-back cache comprising: a CPU including a write-back cache; a main memory configured to store an application program to be executed by the CPU and to serve as a lower stratum of the write-back cache; and a main-memory diagnosis controlling unit configured to diagnose failure of the main memory and including: a memory-access detecting unit configured to detect addresses of the main memory accessed by the CPU from a read signal from the main memory to the write-back cache and a write signal to the main memory; a CPU-memory-access-region storing unit configured to store the accessed addresses of the main memory detected by the memory-access detecting unit from the read signal and the write signal; a diagnosis-memory-access-region storing unit configured to store, in advance, a plurality of regions formed by dividing the application program by the storage size of the write-back cache and to store whether each of the regions is during, after or before diagnosis; a diagnosis controlling unit configured to refer to the diagnosis-memory-access-region storing unit to determine whether the region stored in the CPU-memory-access-region storing unit has yet to be diagnosed, configured to send a diagnosis command for the region if determining that the region has yet to be diagnosed, and configured to send a diagnosis-stop command if the region is cached and also if a write-back signal for the region is received from the CPU-memory-access-region storing unit before a diagnosis-finish signal is received from the diagnosis-memory-access-region storing unit; and a memory diagnosing unit configured to store a preset memory-diagnosis program, configured to execute the diagnosis of the region in response to the diagnosis command sent from the diagnosis controlling unit and to send both a diagnosis-finish signal to the diagnosis-memory-access-region storing unit and a diagnostic result to the CPU, and configured to stop the diagnosis in response to the diagnosis-stop command and to send a diagnosis-stop signal to the diagnosis-memory-access-region storing unit, wherein failure diagnosis of the main memory is executed for each of the regions divided corresponding to the write-back cache, in parallel with the execution of the application program by the CPU.