Dual bus computer architecture utilizing distributed arbitrators and method of using same

Claim 1

A computer system, comprising: a plurality of computer system devices; a plurality of computer system resources; first and second communication buses coupled to each of said plurality of computer system devices and to each of said plurality of computer system resources, for allowing access to one of said plurality of system resources by one of said plurality of computer system devices over said first communication bus and said second communication bus; at least first and second bus access arbitrators, said first bus access arbitrator disposed in a first one of said plurality computer system devices, for allowing a first bus requesting device coupled to said first one of said plurality of computer system devices to access a first one of said plurality of computer system resources over said first communication bus, said second bus access arbitrator disposed in a second one of said plurality of computer system devices, for allowing a second bus requesting device coupled to said second one of said plurality of computer system devices to access a second one of said plurality of computer system resources over said second communication bus; a message bus, coupled to at least one pair of first and second computer system devices, for allowing inter-device communication between at least first and second computer system devices of said at least one pair of computer system devices; wherein said first and second bus access arbitrators cooperate in an event that one of said first and second communication buses is inaccessible while the other of said first and second communication buses is accessible, to allow a bus access arbitrator for said accessible bus to allow access to a non-busy computer system resource by a requesting computer system device utilizing said message bus which allows said first bus requesting device to access said second communication bus through said second computer system device, and said second bus requesting device to access said first communication bus through said first computer system device; said computer system further including a bus arbitrator assignor, for selecting said first bus access arbitrator of said first one of said plurality of computer system devices, for performing bus arbitration of said first communication bus, and for selecting said second bus access arbitrator of said second one of said plurality of computer system devices, for controlling bus arbitration of said second communication bus; wherein said bus arbitrator assignor is operative for reassigning bus arbitration of at least one of said first and second communication buses from at least one of said first and second bus access arbitrators disposed on said first and second one of said plurality of computer system devices, to at least a third bus access arbitrator disposed on a third one of said plurality of computer system devices; and wherein said bus arbitrator assignor re-assigns at least one of said first and second bus access arbitrators upon a failure of at least one of said first and second one of said plurality of computer system devices.

Claim 9

A method of accessing a plurality of computer system resources coupled to first and second communication busses, by a plurality of computer system devices coupled to said first and second communication busses comprising the steps of: requesting access to a first computer system resource over said first communication bus by a first computer system device via a first bus access arbitrator associated with said first computer system device; determining said first communication bus is not busy and accessing said first computer system resource by said first computer system device over said first communication bus; and upon determining said first communication bus is busy, performing the steps of: determining said second communication bus is not busy; and accessing said first computer system resource by said first computer system device over said second communication bus via a second bus access arbitrator associated with said second computer system device.

Claim 10

A method of accessing a plurality of computer system resources coupled to first and second communication busses, by a plurality of computer system devices coupled to said first and second communication busses comprising the steps of: requesting access to a first computer system resource over said first communication bus by a first computer system device via a first bus access arbitrator associated with said first computer system device; determining said first communication bus is not busy and accessing said first computer system resource by said first computer system device over said first communication bus; and upon determining said first communication bus is busy, performing the steps of: determining said second communication bus is not busy; and accessing said first computer system resource by said first computer system device over said second communication bus via a second bus access arbitrator associated with said second computer system device.

Claim 13

An apparatus for providing access to a plurality of computer system resources by a plurality of computer system devices comprising: first arbitration means coupled to one of said plurality of computer system devices and responsive to a first computer system device requesting access to a first computer system resource over a first communication bus, for determining whether said first communication bus is available for access and for allowing said first computer system device to access said first computer system resource over said first communication bus when said first communication bus is available for access; second arbitration means coupled to another one of said plurality of computer system devices, responsive to said first arbitration means indicating that said first communication bus is not available for access, for determining whether a second communication bus is available for access and for allowing said first computer system device to access said first computer system resource over said second communication bus.

Claim 14

An apparatus for providing access to a plurality of computer system resources by a plurality of computer system devices comprising: first arbitration means coupled to one of said plurality of computer system devices and responsive to a first computer system device requesting access to a first computer system resource over a first communication bus, for determining whether said first communication bus is available for access and for allowing said first computer system device to access said first computer system resource over said first communication bus when said first communication bus is available for access; second arbitration means coupled to another one of said plurality of computer system devices, responsive to said first arbitration means indicating that said first communication bus is not available for access, for determining whether a second communication bus is available for access and for allowing said first computer system device to access said first computer system resource over said second communication bus.

Claim 20

An apparatus for providing access to a plurality of computer system resources by a plurality of requesting devices comprising: first and second communication buses, each for providing access to each of said plurality of computer system resources by said plurality of requesting devices; a message bus for providing a communications path between a first one of said plurality of requesting devices and a second one of said plurality of requesting devices; first and second bus arbitrators associated with said first one of said requesting devices and said second one of said requesting devices respectively, said second bus arbitrator configured to allow said first one of said requesting devices to access said plurality of computer system resources via said second communication bus when said first bus arbitrator indicates that said first communication bus is not available for access.

Claim 21

An apparatus for providing access to a plurality of computer system resources by a plurality of requesting devices comprising: first and second communication buses, each for providing access to each of said plurality of computer system resources by said plurality of requesting devices; a message bus for providing a communications path between a first one of said plurality of requesting devices and a second one of said plurality of requesting devices; first and second bus arbitrators associated with said first one of said requesting devices and said second one of said requesting devices respectively, said second bus arbitrator configured to allow said first one of said requesting devices to access said plurality of computer system resources via said second communication bus when said first bus arbitrator indicates that said first communication bus is not available for access.