| 摘要 |
PURPOSE:To make a main CPU highly efficient by dividing a dual port memory into a program storing memory and a data communication memory and switching both the memories by a switching means to connect the switched memories. CONSTITUTION:The dual port memory is divided into the program storing memory 21 and the data communication memory 22. The switching means 23 such as a switch selectively connects a system bus 1 to the memories 21 or 22. At the time of IPL, the system bus 1 is connected to the memory 21, and when an operating state is set up after ending the IPL, the connection of the bus 1 is switched to the memory 22 side. In the constitution, competition between the memory access of a main CPU 12 and memory access from an I/O unit 4 is not generated at the time of operation. Thereby, the rapidity of the main CPU 12 can be maintained independently of the frequency of I/O data transfer and the system can bear load more than the conventional one.
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