NONSYNCHRONOUS CHANNEL/DASD COMMUNICATION SYSTEM

DYNAMIC POLLING DEVICE, MACHINE PROCESSING METHOD, CONTROLLER AND DATA PROCESSING SYSTEM

PURPOSE: To perform synchronous operation without any gap. CONSTITUTION: Multi-bus controllers 18 and 20 are provided which connect CPU channels 22 and 24, and 26 and 28 to DASD device subsystems 60 and 62, and 64 and 66, and an extension channel connection time is secured for the polling of the device. An access signal request from the device is held for a certain period, a channel connection is completed in the period, and the request drops thereafter. Then CPUs 10, 12, 14, and 16 and a controller can freely complete other jobs between polling cycles. A request for an access signal by the device for a connection with a channel making a connection request never interrupts channels and the device even while a communication connection is made. COPYRIGHT: (C)1992,JPO ...

ASYNCHRONOUS COMMUNICATION SYSTEM BETWEEN CHANNEL AND DIRECT ACCESS STORAGE DEVICE

PURPOSE: To obtain a device capable of operating a channel and a device processor even on different fields in addition to their simultaneous operation on the same field. CONSTITUTION: A host processor 10 is connected to a control unit 12 by a channel 11 and the unit 12 and a direct access storage device(DASD) 13 constitute a peripheral data processing subsystem for managing the storing action of the DASD 13. The control unit 12 for operating the DASD 13 controls data transfer between the device and a buffer and between the channel 11 and the buffer. In the format, the channel 11 and the device are mutually independently allowed to execute data transfer. Namely a communication mechanism between channel interface processing and device interface processing in the unit 12 can be obtained. COPYRIGHT: (C)1992,JPO ...