Browse Prior Art Database

Improved Memory System

IP.com Disclosure Number: IPCOM000098071D
Original Publication Date: 1961-Dec-01
Included in the Prior Art Database: 2005-Mar-07
Document File: 2 page(s) / 41K

Publishing Venue

IBM

Related People

Bruce, GD: AUTHOR

Abstract

Bistable magnetic cores of various materials, including ferrites, experience a relaxation effect in response to application of certain driving fields. This effect is manifested as a sharp reduction in the switching threshold of the core. This is that level of driving field which must be exceeded before substantial irreversible flux switching can be produced. The effect is only temporary and the relaxed threshold is observed to increase with time until it eventually regains its normal value. The time during which the threshold is significantly below its normal value varies, depending upon the material involved and the characteristic of the driving field. It may last for as much as several microseconds after termination of the driving field in some cases.

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Improved Memory System

Bistable magnetic cores of various materials, including ferrites, experience a relaxation effect in response to application of certain driving fields. This effect is manifested as a sharp reduction in the switching threshold of the core. This is that level of driving field which must be exceeded before substantial irreversible flux switching can be produced. The effect is only temporary and the relaxed threshold is observed to increase with time until it eventually regains its normal value. The time during which the threshold is significantly below its normal value varies, depending upon the material involved and the characteristic of the driving field. It may last for as much as several microseconds after termination of the driving field in some cases. The driving field which produces the effect must be well above the static switching threshold of the core, but it may be of such short duration that it only produces a nominal flux change.

Use is made of this relaxation effect to improve the operation of a two-core per bit memory system. The left drawing shows a partial two-core per bit array for storing m words of n bits each. Each bit storage cell comprises two cores A and B having hysteresis characteristics as shown at the upper right. Information is represented by the relative states of the two cores of each cell. If A resides at remanence B1 and B resides at B2, a binary one is stored. If A resides at B2 and B at B1, a binary zero is stored.

The information is read out by driving both cores to -Br and sensing the polarity of the net difference signal induced in the sense winding coupling the two cores.

All of the bit drivers of the array are normally ON. The bit curren...