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Priority Update for Message Switching

IP.com Disclosure Number: IPCOM000075253D
Original Publication Date: 1971-Aug-01
Included in the Prior Art Database: 2005-Feb-24
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Stoner, I: AUTHOR

Abstract

The determination of whether the processing priority of an input message is to be updated in a "Store and Forward" (SF) message switching program can be made without the necessity of performing an additional disk access. Previous SF message switching programs require an additional disk access, should it be necessary or desirable to make this determination.

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Priority Update for Message Switching

The determination of whether the processing priority of an input message is to be updated in a "Store and Forward" (SF) message switching program can be made without the necessity of performing an additional disk access. Previous SF message switching programs require an additional disk access, should it be necessary or desirable to make this determination.

In a SF message switching program, incoming messages are queued by priority. Each input queue is maintained on disk with pointers to the queues maintained in core by Queue Definition Blocks (QDBs). To process an input message, it is necessary to bring the header segment into core, thereby causing a disk access. To update the message priority, it has also been necessary to bring the header segment into core, thereby causing a disk access. Hence, an additional disk access has been required each time the processing priority of a message is to be updated.

The additional disk access may be eliminated by keeping the header segment of the first message of each nonempty input queue in core. The location in core of this header segment is maintained in the input QDB. Thus, it is only necessary to go to the header segment to determine whether the processing priority is to be updated. If it is to be updated, the message is removed from its input queue by a "Get Header from Input Queue" macro- instruction and placed on another priority input queue by a "Put Header on Queue" macro-instru...