| 摘要 |
PURPOSE:To transfer independently data at a high speed between memories on a CPU bus and a DMA (direct memory access) bus in parallel to the actuation of a CPU, by concentrating the functions of a DMA controller to an area to perform the multiplexed transfer of data as well as the control of the DMA bus. CONSTITUTION:When a flexible disk is copied for instance, a flexible disk controller 15 receives a control parameter from a CPU bus 4 to read out the contents of a flexible disk device 9 and sets these contents to a shared memory within a read controller 15. Thus a CPU1 gives an order to a controller 5 via the controller 15 to transfer the contents of the device 9 to a magnetic disk device 8 of a magnetic disk controller 17 via a DMA bus 7. Then the CPU1 gives a command to the controller 17 to perform writing to a magnetic disk through the bus 4 and then receives an end signal of writing. Thus a copying action is through. |
