SYNCHRONISIERUNG UND VERARBEITUNG VON SPEICHERZUGRIFFSOPERATIONEN

A synchronising scheme for processing "locked" memory access requests from various computer system units is provided by a System Control Unit (SCU) (14). The SCU is provided with a directory of lock bits in such a way that each memory address associated with a memory access request is mapp...

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Bibliographic Details
Main Authors ARNOLD, SCOTT, DELAHUNT, STEPHEN J, FOSSUM, TRYGVE, KANN, JAMES
Format Patent
LanguageGerman
Published 15.08.1997
Edition6
Subjects
CALCULATING
COMPUTING
COUNTING
ELECTRIC DIGITAL DATA PROCESSING
PHYSICS
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Summary:A synchronising scheme for processing "locked" memory access requests from various computer system units is provided by a System Control Unit (SCU) (14). The SCU is provided with a directory of lock bits in such a way that each memory address associated with a memory access request is mapped to a corresponding location in the lock directory. Incoming requests for a given memory location are processed by interrogating the corresponding lock bit in the lock directory. If the lock bit is not set, the request is granted. The lock bit is subsequently set and maintained in that state until the unit requesting the lock has completed its memory access operation and sends an "unlock" request. If the interrogated lock bit is found to be set, the lock request is denied and the requesting port is notified of the denial and requested to try again. Fairness is incorporated in the processing of denied lock requests by means of a reserve list onto which denied requests are sequentially positioned on a first-come-first-served basis.
Bibliography:Application Number: AT19900300385T