| 摘要 |
PURPOSE:To reduce the deviation of data transfer between channels, by providing plural transfer request signals between a data buffer and a main storage provided to each channel and generating a transfer request signal of higher priority as the transfer data quantity increases. CONSTITUTION:An input/output controller consists of a common part 10 and plural channel parts 30. When data is transferred to a peripheral controller 5 from a main storage 2, a transfer request signal 35 is delivered to a common control part 12 from a data transfer control part 34. At the part 34 a high or low priority signal is sent to the part 12 by switching and in response to the number of words to give access to the storage 2 for the data stored in a data buffer 32. The part 12 selects a channel part of the highest priority among the transfer request signals given from the channel parts 30. Then the data is read out of the storage 2 to a data register 13 with a main storage address related to the above-mentioned channel part. An access end signal 36 is sent to the channel part 30 as a reply. The channel part 30 fetches the readout data out of the register 13 to a writing register 31 and then stores it into the buffer 32. |
