Data server for transferring selected blocks of remote file to a distributed computer network involving only single data transfer operation

摘要

A pipelined data server having an improved data transfer architecture is used with a distributed computer network and a plurality of secondary storage devices to efficiently transfer data between the network and the secondary storage devices. The pipelined, multiprocessor data server includes a common inter-processor bus that connects one or more communication processors and file processors to one or more device processors, each having a buffer memory as part of the device processor. The common bus provides for global direct access to each of the buffer memories in the device processors by any of the other processors. The buffer memories are also connected to the secondary storage device attached to the device processor by a DMA transfer path in the device processor. In this way, data transfers can occur between the secondary storage device and the network with only one data transfer across the common bus. The data transfer architecture of the device processor of the present invention is also organized in a pipelined manner so as to allow for multiplexed data transfers among the microprocessor, bus interface, I/O controller and buffer memory which comprise the device processor.