Browse Prior Art Database

Optimizing Process for Page to Page Frame Binding Duration

IP.com Disclosure Number: IPCOM000082190D
Original Publication Date: 1974-Oct-01
Included in the Prior Art Database: 2005-Feb-28
Document File: 5 page(s) / 28K

Publishing Venue

IBM

Related People

Lassettre, ER: AUTHOR [+2]

Abstract

This is a page replacement process utilizing a set of "Interreference Interval Probabilities" in making page replacement decisions.

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Optimizing Process for Page to Page Frame Binding Duration

This is a page replacement process utilizing a set of "Interreference Interval Probabilities" in making page replacement decisions.

Reduction of page traffic, by reducing the number of incorrect page replacement decisions is a goal shared by all paging supervisor designs. The generalized page replacement algorithms tend to make more incorrect page replacement decisions for pages involved in conversational/interactive processes, because these pages generally have interreference intervals that are orders of magnitude longer than nonconversational processes.

This technique reduces the number of incorrect steal decisions made, by advising the paging supervisor of a specific page's expected inter-reference time and the probabilities thereof.

The paging supervisor uses this information when such a specified page has become a candidate (via existing criteria) for page replacement, as an additional criterion to be met. In order to accurately apply the inter-reference probabilities, the Operating Systems' paging supervisors must be changed to mark designated pages as special, and to time stamp them upon paging them in. When such a page has become a candidate for page replacement, the paging supervisor must determine the actual inter-reference interval and use this value as an index to a Probability Table.

The accessed probability value is then employed in the page replacement decision. Such a process can be applied to a single group of "different" pages - those involved in conversational/interactive processes, or to multiple groups of pages (each group having a different set of interreference interval probabilities) simply by making provision for multiple Probability Tables.

The accessed probability value is then employed in the page replacement decision. Such a process can be applied to a single group of "different" pages - those involved in conversational/interactive processes, or to multiple groups of pages (each group having a different set of interreference interval probabilities) simply by making provision for multiple Probability Tables.

To place all the following disjoint processes in perspective, the following composite is offered.

To effect different page-in and page-out algorithms for teleprocessing (TP) the following must be done, otherwise the normal (existing) system actions prevail: The user will specify:

Which of his TP applications are response time consistency

dependent.

A probability curve that has a relationship to the think

time characteristics of the crucial application(s).

The VTAM subsystem will specify to the paging supervisor: Which VTAM pages associated with user designated

application are crucial (and must be main stored resident)

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to the rapid execution of the service being rendered.

The paging supervisor will employ the special algorithm when stealing pages that VTAM has indicated are "special".

The different page-in characteristic is achi...