Browse Prior Art Database

Frequency and Recentness of Use Indicators

IP.com Disclosure Number: IPCOM000091451D
Original Publication Date: 1968-Feb-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 3 page(s) / 52K

Publishing Venue

IBM

Related People

Anderson, JL: AUTHOR

Abstract

It is useful in data processing systems to obtain an indication of the relative frequency of use and recentness of use of devices, registers, or other system parameters. For example, in a time-shared data processing system it is desirable to maintain such records of use of page-sets of information, particularly when it becomes necessary to replace an old unused page with a new page just acquired from remote storage. At such times, the records of use can be referenced to select an associated page assignment register in which to record the location assignment of the new page without displacing a possibly equally important and current assignment.

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Frequency and Recentness of Use Indicators

It is useful in data processing systems to obtain an indication of the relative frequency of use and recentness of use of devices, registers, or other system parameters. For example, in a time-shared data processing system it is desirable to maintain such records of use of page-sets of information, particularly when it becomes necessary to replace an old unused page with a new page just acquired from remote storage. At such times, the records of use can be referenced to select an associated page assignment register in which to record the location assignment of the new page without displacing a possibly equally important and current assignment.

For maintaining such records of use, analog devices can be employed. For example, a number of capacitors C1...Cn, as shown at B, are individually associated with a corresponding number of page location assignment registers, R1...Rn as at A. Diodes D1...D3 and the logic and control circuits in the path leading to each capacitor control the charge on the capacitor. Such charge corresponds to the rate and recentness of reference to the page whose location is designated by the associated register. An output indication of the least charged capacitor is obtained as follows.

Considering drawings A and B, when an internally loaded page is referenced Page Is Loaded, the occurrence in coincidence of the page gating impulse Read and the page designating signal Page Name operates through the corresponding And-Or pair in B to increase the charge on the corresponding capacitor by a predetermined amount. In this manner the capacitors build up different amounts of charge depending upon the frequency of application of pulses to them and the known rate of decay of the charges. The latter relate to the recentness of the last impulse received by each capacitor.

When a new page is referenced Page is Not Loaded...