International Business Machines Corporation

Timothy Lee Toohey

Yang Liu

Lawrence Yiumchee Chiu

Paul Henri Muench

George Henry Ahrens, Jr

George John Dawkins

Michael Youhour Lim

For a high availability cache, a cache module obtains permission to manage the cache in response to a failover event in a server cluster by communicating a cache coherency token. An update module rebuilds a cache directory from data stored in the cache and accesses the cache without reloading the data stored in the cache.

High availability cache in server cluster

A method and apparatus for detecting an error condition during initialization of a multiprocessor data processing system is provided. A master processor identification indicator is initialized to an initial value by a service processor in the data processing system. The master processor identification indicator may be a location in nonvolatile RAM to protect data integrity. One of the plurality of processors in the multiprocessor system is selected to be the master processor by being released by the service processor and winning the &ldquo;race condition&rdquo; to fetch the first instruction from memory for program execution. This processor then sets the master processor identification indicator to a unique processor identification value. The initial value may be a spoof number indicating whether the master processor has yet written its unique processor identification value. At some later point in time, the service processor detects a freeze or hang condition in the data processing system. The service processor reads the value of the master processor identification indicator and reports the value of the master processor identification indicator to indicate which processor among the plurality of processors in the data processing system was selected as the master processor prior to the detection of the hang condition.

Method and apparatus for problem identification during initial program load in a multiprocessor system

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Austin, TX, United States of America

Timothy Lee Toohey