| 摘要 |
PURPOSE:To transfer data efficiently by comparing a data transfer request from each module with the data transfer capability of a common bus and deciding whether transfer is permitted or not in accordance with the comparison result. CONSTITUTION:If a channel module CA 1(0) is started by a channel, for exam ple, 5(0) out of CHs 5(0)-5(3) for the purpose of writing data in a device adapter module DV 6(0) out of DVs 3(0)-3(3), the CA 1(0) reports the data transfer speed on a common us 2 to an RM 4 and requests acquisition of the use right to the bus 2. Then, the RM 4 stores the data transfer speed value accompanied with this request in a register 41 and operates prescribed data in an arithmetic part 42 and stores it in a register 44. This output is compared with a preliminari ly stored maximum data transfer capability value of the bus 2 by a comparator 45, and the output is rejected if data of current transfer exceeds the maximum data transfer capability of the bus 2. |
