| 摘要 |
PURPOSE:To reduce the number of frequencies of subchannel code loading in the course of input/output processing of multiplexing operation and improve the throughput, by installing a subchannel updating bit, an old I/O address register, etc., to the data channel device of a data processing system. CONSTITUTION:A local storage 21, arithmetic device 23, multiprocessor, etc., are installed to the CPU2 of a data processing system. Moreover, a multiprocessor 34, controlling registers 311-316, subchannel updating bit 32, and old I/O address register 33 are installed to a data channel device 3 connected to the CPU2. When only subchannel information accumulated in the subchannel device 3 is updated, the bit 32 is turned on and the subchannel storing is executed. In case where the next input/output processing from an input/output interface 35 exists, subchannel loading is performed only when the machine number of the input/ output device coincides with the machine number of a previously processing device and, at the same time, the bit 32 is off. Thus the throughput is improved.
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