| 摘要 |
PURPOSE:To control a data transfer speed from a data cash device to an input/ output controller according to a transfer time, by measuring the transfer time of data between a channel and the input/output controller with an input/output device. CONSTITUTION:A data request is outputted from a signal line 22, and a time from the generation of data request to the return of data response given from a signal line 23 is measured to obtain an effective transfer speed. Next, the effective transfer speed is transmitted to a data cash device 16 via a transfer speed informing (SPST) signal line 28. The device 16 transfers data to a channel when the data transfer request from a channel exists in this effective transfer speed. When the 1st data request signal DVDRQ is outputted from the device 16, an input/output controller 14 returns the 1st data response signal DVDRP to the device 16, and the 2nd data request signal CHDRQ is transferred to a channel 13 after the internal delay time of the device 14. The request signal CHDRQ turns off with the leading of the 2nd response signal CHDRP from the channel 13. |
