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Logical Push Down List

IP.com Disclosure Number: IPCOM000091554D
Original Publication Date: 1968-Mar-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 2 page(s) / 38K

Publishing Venue

IBM

Related People

Liptay, JS: AUTHOR

Abstract

This logic is an implementation of an algorithm which monitors the activity or use of a number of data processing system, information hearing units. When called upon, the logic selects one of the units which is to have the information replaced with new information to be used by the system. The logic selects the unit which is unused for the longest period of time as the one to be replaced. This algorithm is termed push-down.

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Logical Push Down List

This logic is an implementation of an algorithm which monitors the activity or use of a number of data processing system, information hearing units. When called upon, the logic selects one of the units which is to have the information replaced with new information to be used by the system. The logic selects the unit which is unused for the longest period of time as the one to be replaced. This algorithm is termed push-down.

The logic monitors the activity of four units. The four units are loaded with information for use by a system and subsequently referenced for use in a random sequence. When it becomes necessary to replace the information in one unit with new information, the logic provides an indication of which of the units is the longest unused one. To monitor four units, six triggers are provided. Each trigger is set or reset to indicate the sequence of use of a particular unit in relation to all other units being monitored. For example, triggers 1, 2, and 3 indicate relative activity between unit 1 and all other units. Triggers 4 and 5 monitor the activity of unit 2 with regard to units 3 and 4. Trigger 6 monitors the activity of unit 3 with regard to unit 4.

The triggers are coded so that the set state corresponds to a particular unit which is more recently referenced with regard to the other unit monitored by that particular trigger. When a trigger is reset, it corresponds to the other unit which is more recently referenced. When a...