Multi-computer system with plural serial bus loops

Claim 1

A multi-computer system comprising: a plurality of data processors; at least one input/output device; a first layer of serial bus loop hierarchy including a plurality of serial bus loops, each being coupled with at least one of said data processors; a second layer of serial bus loop hierarchy including at least one serial bus loop coupled with said at least one input/output device; respective interbus linkage devices coupling the respective serial bus loops of said first layer with the serial bus loop of said second layer, the input/output device coupled with said second layer serial bus loop being accessible by the data processors coupled with at least two of said first layer serial bus loops through said first layer serial bus loop, a linkage device, and said second layer serial bus loop; a plurality of stations, each station coupling a data processor or the input/output device to a serial bus loop; each of said interbus linkage devices and said stations including means for sending and receiving a transfer frame carrying information between a data processor and said input/output device and comprising at least an input/output address field including a plurality of sub-fields for storing addresses representing a map of those of the linkage devices and the stations which are to be passed, in that order, by the transfer frame sent between one of the processors and the input/output device, respectively, and a control code field; and each one of said interbus linkage devices coupling the first and second layer serial bus loops including an address register for storing an address of the interbus linkage device on the associated first layer bus loop, means connected to said address register for detecting coincidence between the content of said address register and the content of a predetermined one of the sub-fields of the input/output address field of the transfer frame received from said associated first layer bus loop, means responsive to detection of coincidence by said detecting means for modifying said received transfer frame by shifting the content of the input/output address field thereof by one sub-field length and means for sending the modified frame to the associated second layer serial bus loop.