| 摘要 |
PURPOSE:To execute the synchronization establishment of a transmitting and receiving command by storing the ending condition of the transmitting and receiving command on a common bus interface with a command synchronization establishing circuit and informing of it in correspondence to an access from a main body device. CONSTITUTION:A main device 1 has a central control device, a main memory to be connected to this control device and a channel device to be connected to the central control device in duplex constitution. An input and output control device 3 is connected through these channel devices and a common bus interface 2 and the reception of data from a line and the transmission of the data of the main memory are executed by DMA operation with being not-synchronized. In this input and output control device 3, a command synchronization establishing circuit 4 is provided and the ending condition of the transmitting and receiving command on the interface 2 is stored and informed an input and output control device firmware according to the access from the device 1. Thus, the synchronization of the command can be obtained between the device 1 and the device 3. |
