Unisys Corporation

Doug E Morrissey

Penny L Svenkeson

John A Miller

Philip J Erickson

Peter C Wilson

Robert J Gulick

A method and apparatus is disclosed for initiating execution of selected application processors in a clustered multiprocessor system without disrupting the addressing mode of the processors. In one embodiment, this is accomplished by initializing the processors in a conventional way, setting the addressing mode, and then leaving each of the processors in an active mode spinning on a designated Startup Address Location. To start an application processor, the OS simply write a target processor ID and a desired start-up address into the Startup Address Location. The application processor with the matching processor ID reads the Startup Address Location, jumps to the address specified in the Start-Up Address code section, and begins execution at that location. In another embodiment, a processor is provided that does not switch addressing modes when switched from a halt state.

Method and apparatus for initiating execution of an application processor in a clustered multiprocessor system

A method and apparatus for increasing the routing bandwidth of interrupts between cluster manager devices in a clustered multiprocessor system is disclosed. This is accomplished by providing special cluster manager devices that can convert &ldquo;N&rdquo; serial messages received from a local APIC to &ldquo;M&rdquo; parallel messages, wherein M is less than N. The special cluster manager device then transfers the &ldquo;M&rdquo; parallel messages to a receiving cluster manager device. The receiving cluster manager device converts the &ldquo;M&rdquo; parallel messages into the original &ldquo;N&rdquo; serial messages, and sends the &ldquo;N&rdquo; serial messages to the appropriate local APIC within the receiving cluster.

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Allentown, PA, United States of America

Doug E Morrissey