International Business Machines Corporation

Larry J Cravens

Jay Paul Kurtz

Kenneth Charles Vossen

Glen Warren Nelson

Kenneth Gerald Linn

Donald L Ward

Edwin C Grazier

John Michael Attinella

Michael James Denney

David Ferguson Legler

A method utilizes a virtual flight recorder to harvest a subset of events being collected by an active system tracing facility during operation of a computer system. The virtual flight recorder is 'virtual' from the sense that it is not specifically instrumented into a component with which the virtual flight recorder is associated, which eliminates the burden on developers to specifically instrument components of interest, and minimizes the impact on system performance as a result of performance metric collection.

Virtual flight recorder hosted by system tracing facility

A method, apparatus and computer program product are provided for implementing feedback directed deferral on nonessential direct access storage device (DASD) operations. A kernel DASD I/O manager maintains a queue depth count value for a DASD unit and maintains a busy flag that indicates when the queue depth count value is greater than a predefined threshold. The kernel DASD I/O manager defers optional operations responsive to the busy flag being set for the DASD unit.

Implementing feedback directed deferral of nonessential DASD operations

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Pine Island, MN, United States of America

Larry J Cravens