Browse Prior Art Database

NDRO Magnetic Film Memory

IP.com Disclosure Number: IPCOM000095706D
Original Publication Date: 1964-May-01
Included in the Prior Art Database: 2005-Mar-07
Document File: 2 page(s) / 37K

Publishing Venue

IBM

Related People

Bareham, WC: AUTHOR [+3]

Abstract

The magnetic film memory employs a method of non-destructive readout (NDRO) of stored information. Thin film storage cell 11 is subjected to a small bias field in the positive hard direction +HD.

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NDRO Magnetic Film Memory

The magnetic film memory employs a method of non-destructive readout (NDRO) of stored information. Thin film storage cell 11 is subjected to a small bias field in the positive hard direction +HD.

To write in the information to be stored, a word drive pulse is generated by word driver 12. It is applied to word line 13 and exposes the magnetization of cell 11 to a word drive field. This is in the same hard direction +HD to the effect that the resulting write field exceeds the coercive force H(K) of the film. A bit pulse generated by bit driver 14 is applied to bit line 15 when the word drive pulse ceases. Such provides an overlap current and a directional bit field applied along the easy direction ED of cell 11 to store 1 or 0.

To read out the information stored, a word drive pulse of equal magnitude but opposite polarity as for write-in is applied to word line 13. It exposes the magnetization of cell 11 to a word drive field in the negative hard direction -HD. Magnetic flux changes along the easy direction ED are picked up by sense line
16. The induced readout signal is amplified by sense amplifier 17. Because the superposition of bias field and word drive field results in a read field with a field strength below the coercive force HK of the film, readout of the information stored takes place in a non-destructive fashion.

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