Abstract: An information processing apparatus includes a processor, a memory, and a cache. Information read from the memory by the processor is stored in the cache. The processor writes the information stored in the memory in all of the regions of the cache at a predetermined timing.

Abstract: In a data processing system including a plurality of multi-processor systems, each multi-processor system having at least one central processing unit and at least one main memory both connected to a memory control unit, each memory control unit is connected to each other memory control unit, the memory control unit comprises plural ports, plural registers, access selection circuits for innner and outer access, a priority control circuit, a first and a second control circuit, and wait signal reset circuit, a priority of accesses from the same central processing unit to the other multi-processor system is detected, and the registers to store the access request signals in the other multi-processor system are efficiently used by adding a priority control signal to the access request signal. Thus, the data throughput of the system and the speed of the access are improved.

Abstract: The present invention relates to an access request control apparatus and more specifically to an apparatus for determining priority between a plurality of access requests in a memory control apparatus which uses a pipeline. One of the access requests from a plurality of channel processing devices CHP's is selected by a first priority determination circuit. The selected CHP request, the requests from a plurality of central processing units and the request in the loop-back of the pipeline control circuit are considered for selection by a second priority determination circuit. In case a CHP request, selected by the first priority determination circuit, is not selected by the second priority determination circuit or selected but nullified in the course of the pipeline, the CHP request is returned to the first priority determination circuit. But, in this case, a higher priority is given to the CHP request in the first priority determination circuit.

Abstract: A data processor system includes a plurality of multiprocessor systems, and each multiprocessor system is connected through each memory control unit of each multiprocessor system. Each multiprocessor system comprises a memory control unit, at least one central processing unit, at least one channel control unit, and at least one main memory unit. The central processing unit, channel control unit, and main memory unit are connected to the memory control unit via interface lines. The memory control unit comprises at least two pipelines and at least two access requests to the main memory unit belonging to the pipe-line, and the other pipe-line is used for access requests to another main memory unit belonging to another memory control unit.

Abstract: This invention relates to a system for processing access requests issued from a plurality of access requesting units to a memory. In particular, in a storage system where the buffer storage BS and main storage MS are provided, access is first made to BS based on and access request and if the desired data is not found in BS, access is made to MS. When the desired data is not found in BS and access is then made to MS, acces to BS is carried out based on the next access request from the same access requesting unit in parallel with the access to MS by the first access request.