| 摘要 |
PURPOSE:To make continuous access of data possible to shorten the processing time by writing data, which is sent continuously through the DMA mechanism of an external device, in a logical device successively and sending data read out from the logical device to the external device through the DMA mechanism. CONSTITUTION:A command sequential execution control circuit 241b of a command sequencer 241 sends an access command stored in a register CR to logical devices 21-23 designated by a register USR and sends a command signal, and the command is executed to write data, which is stored in the memory of a service processor, in a main storage device through a data buffer 241c. Contents of a register LR of a command storage part 241a are counted down each time when data is transferred, and the data load operation is stopped when they become zero. Meanwhile, a signal Data Ack for data read is sent from the circuit 241b to a DMA control circuit 130. |
