PURPOSE: To make it possible to execute a different channel program while one channel program is being executed by a corresponding channel by shortening an in-use state of a channel as much as possible.
CONSTITUTION: Data transfer starts by a coincidence between WRITE command (indication of CC) A from CH4-2 and READ command (no indication of CC) B from CH4-1. In accordance with contents of a flag indicated together with A, inter-computer coupler 5 reports only CHE as status information to 4-2 to release temporarily CHs 5 and 4-2 on an I/O interface from a coupling state. To 4-1, on the other hand, simultaneous report 21 of CHE and DUE in accordance with contents of a flag reported together with above-mentioned B cause an interruption of a processor (not shown in the figure) and also actuates 4-1 through coupler 5, so that when a coincidence with a device address corresponding to a channel program in an interruption state is obtained, the program will be restarted.
KOYANAZU IKUROU
YASUMI NAOAKI
YAMAGA MITSUHIRO
NARITA YUUICHI
NIPPON ELECTRIC CO
HITACHI LTD
FUJITSU LTD