INPUT AND OUTPUT PROCESSING SYSTEM

摘要

PROBLEM TO BE SOLVED: To evade the sinking of a DE report (a state where a DE report cannot be performed) and to improve the processing performance of a computer system by sparing a non-connection time when a DEV (input/output device) can perform the DE report. SOLUTION: An MS(main storage) 2 includes a control table UCW corresponding to a device and a DE report wait control word WDECW corresponding to a channel device and a channel path CH. The path CH includes a start suppression control word ISCW and a current time register TOD. Then each of CH 40 and 41 decides whether the DEV 50-53 have the sufficient non- communication time on the CH to perform the DE reports or whether any DEV is not performing the DE report under the control of the CH to detect the possibility of the sinking of the DE report. Thus, the CH selection is temporarily suppressed for the CH that has the possibility of the sinking of the DE report. Thus, a time is spared for receiving the DE report from a DEV.