| 摘要 |
PURPOSE:To make parallel processing when plural processing requests compete each other to the same magnetic disk device, by selectively sending a select signal and selecting level signal when the magnetic disk device is accessed from two separate systems. CONSTITUTION:A disk cash 5 holds the copy of data stored in magnetic disk devices 8 (8-0-8-7). When data to be read as a form of data transferring exist in the cash 5, there are two forms: one form in which data are transferred to the disk device 8 through magnetic disk controlling device DKC 3-A and DKC 3-B, and the other form in which data read out from the disk device 8 are written in the cash 5. In addition to the above, another form in which data are transferred from the disk device 8 to a block multiplexer channels BMC 2-A and BMC 2-B through the controlling devices DKC 3-A and DKC 3-B. Because of the forms mentioned above, simultaneous processing can be executed when the controlling devices DKC 3-A and DKC 3-B are different even when the magnetic disk device 8 to be accessed is the same. |
