| 摘要 |
PURPOSE:To improve the working efficiency of a system by accessing a main memory by a diagnostic device, diagnosing the main memory only in the case of cache hit and interrupting the diagnosis of the main memory in the case of cache miss. CONSTITUTION:When data are read or written, at first, the access to a cache memory 11 is tried. In the case of the cache hit, the cache memory 11 is accessed and the data are read or updated. Then, a diagnostic device 3 accesses a main memory 2 and diagnoses the main memory 2. In the case of the cache miss, the main memory 2 is accessed and the data are transferred to the cache memory 11 and read or updated. Then, the diagnosis of the main memory 2 is interrupted and the confusion of the data in the main memory 2 is avoided. Thus, even while the system works, the diagnosis of the external memory 2 can be executed by a diagnostic program and the reliability of the system is improved without lowering the working efficiency of the system. |
