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Store Pad (Clear Line) Service Mechanism

IP.com Disclosure Number: IPCOM000045671D
Original Publication Date: 1983-Apr-01
Included in the Prior Art Database: 2005-Feb-07

Publishing Venue

IBM

Related People

Authors:
Krygowski, MA [+details]

Abstract

Certain processor operations require that main storage (MS) be initialized totally or in dIscrete parts. For example a program moving a short character string into a large MS area has need to pad the remainder of the MS area with a padding character. When each central processor (CP) in a multiprocessor (MP) configuration has a store in cache, it need not hold the padded part of the MS area in its local cache, since to do so would be time consuming. Since old copies of that MS area may reside In cache locations of other CPUs, directory searches must be made to insure that any old copies in various cache locations are invalidated. The pad character must be stored in such a way that there is no chance of old modified data being able to overwrite the new padded MS area.