Maspar Computer Company

Mark P McKee

John R Nickolls

John Zapisek

William T Blank

David M Bulfer

John M Long

To effect a block data transfer between a plurality of physical I/O devices coupled through interfaces to an I/O channel ('IOC') bus, a source logical device is established by programmably assigning to each of the physical device interfaces a logical device identifier, a leaf identifier determining when the physical device participates relative to the first data transfer in the block data transfer, a burst count specifying the number of consecutive transfers for which the physical device is responsible when its interleave period arrives, and an interleave factor identifying how often the physical device participates in the block data transfer. A destination logical device is similarly established. The source and logical devices are then activated to accomplish a block transfer of data between them. To permit different I/O processors to operate independently in making I/O requests, requests from each I/O processor are communicated to an IOC controller over another bus, which need not be a high performance bus, and are serviced to construct header packets in a transaction buffer identifying IOC transactions, including source and destination logical devices. When each packet is finished, the responsible I/O processor puts a pointer into a transaction queue, which is a FIFO register. Each IOC transaction is initiated as its corresponding pointer is popped from the transaction queue. Apparatus embodiments are disclosed as well.

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Alameda, CA, United States of America

Mark P McKee