| 摘要 |
PURPOSE:To use effectively a real channel and to divide a load of a channel by not fixing a path tying a CPU and an IO device and by assigning properly a real channel in the idle state when an input/output request is given. CONSTITUTION:An IO request control unit 3 obtains an address of an IO device being an object of an input/output from an IO request generated from a CPU1, issues a real path assigning request to a real path control unit 5 and checks the presence of an idle time of real path and an IO device being an object of the input/output. A real channel assigning request is issued to a real channel control unit 4 at the same time so as to check the presence of an idle of a real channel in matching with the IO device being an object of the input/output. When each request is satisfied, real channel assigning instruction, a real path assigning instruction and an input/output start instruction are issued further. If the requests are not satisfied, the IO request is connected to a real device stand-by cue so as to await that the real device becomes idle. When any idle device exists, various instructions same as above are issued. |
