| 摘要 |
PURPOSE:To transfer always most suitably transfer data to flexibly operate a system by designating a data transfer format between an I/O device and a main storage device in accordance with the transfer format instruction from a central controller. CONSTITUTION:In case required data is continuously transferred between an I/O device 2 and a main storage device 2 through a processor bus 4, a central controller 1 transmits a transfer start instruction DIO, where transfer formaty indication L/I is set to a continuous mode I, to the I/O device 3 through the bus 4. At the time of deciding that the device 3 itself and the mode I are designated, a switching means 300 of the I/O device 3 starts a continuous transfer means 100. Then, the means 100 occupies the bus 4 for a prescribed time and data is continuously transferred between the means 100 and the device 2. If the means 300 decides that the instruction DIO designates a mode L, an interrupting means 200 is started and the means 200 performs the successive transfer of the segmented data as well as performs the interrupted transfer to release the bus 4 at each transfer end time between the device 2. |
