International Business Machines Corporation

William T Higgins

Michael T Benhase

Florence J Clark

Serge Mirabeau

Patrick E Anderson

Roland J Bunten

Ronda J Hruby

A multi-path controller is disclosed for connecting CPU channels with DASD device subsystems. Extended channel connection time are accommodated in the polling of the devices. The request for access signals for the devices are retained for a period of time during which channel connection should be completed and then dropped. The CPU and the controller are freed to complete other work in between the polling cycles. The requests-for-access signals by the devices for connection to the channel that requested the connection does not tie up the channels and the devices while communication is being made.

Dynamic polling of devices for nonsynchronous channel connection

High availability is achieved in a multiprocessor system by grouping the processors into two clusters operating on different clock and power boundaries. In each cluster is an array containing a substantially identical copy of the system information relating to the operation of the processors. Each processor has a local port for accessing the local array and a remote port for accessing the remote array. When an update is made on the system information, it is made on both the local and remote arrays with the remote update performed transparently.

Multiprocessor system architecture with high availability

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San Jose, CA, United States of America

William T Higgins