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Sequenced Readout in a Bubble Domain Associative Memory

IP.com Disclosure Number: IPCOM000041624D
Original Publication Date: 1984-Feb-01
Included in the Prior Art Database: 2005-Feb-02
Document File: 3 page(s) / 44K

Publishing Venue

IBM

Related People

Chang, H: AUTHOR [+2]

Abstract

A bubble domain associative memory is shown in IBM Technical Disclosure Bulletin 18, 598-602 (July 1975). This associative memory uses a plurality of bubble loadable latches comprised of magnetic elements which can hold a bubble domain. Depending upon the presence or absence of a current in an associated conductor, bubble domains will be loaded onto the latches. The presence of the domains on the latches will determine whether subsequent domains will be allowed to pass through or deflect along a different path. This reference not only identifies matched shift registers but also seals off the mismatched shift registers. The present structure enables a sequenced readout to occur after multiple matches are made in an associative memory, such as that described in the aforementioned reference.

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Sequenced Readout in a Bubble Domain Associative Memory

A bubble domain associative memory is shown in IBM Technical Disclosure Bulletin 18, 598-602 (July 1975). This associative memory uses a plurality of bubble loadable latches comprised of magnetic elements which can hold a bubble domain. Depending upon the presence or absence of a current in an associated conductor, bubble domains will be loaded onto the latches. The presence of the domains on the latches will determine whether subsequent domains will be allowed to pass through or deflect along a different path. This reference not only identifies matched shift registers but also seals off the mismatched shift registers. The present structure enables a sequenced readout to occur after multiple matches are made in an associative memory, such as that described in the aforementioned reference. In contrast with other art which does this off the bubble domain chip, the present structure is completely on the bubble chip. An associative search may identify none, one, or many words. For multiple match situations, a structure and a scheme will be described for reading out the matched words in sequence without overlaps or gaps. In addition to a column of loadable latches for associative search, the sequential readout structure employs another column of loadable latches for read-enable, and a third column of loadable latches (also serving as a compressor) for sequencing interrogation. The device structure includes three latches L1, L2, L3 in the passage from each shift register to the readout detector. Latch L1 is a search latch which, after the search operation, remains open for a match and closed for a mismatch. Latch L2 is a read-enable latch, which, after having received a bubble from the sequencing latch, will transmit a bubble from the adjacent search latch, and after having the bubble stream transmitted, delivers a bubble to seal the search latch. Latch L3 is a sequencing latch, which is part of a compressor having idlers I1, I2, I3 and I4 . Idlers I1, I2 and I4 are always loaded. The I3 idlers and the compressor are first loaded from the search latch L1 to register which shift registers are mismatched, and then receive a bubble at a time from one end to open up the passages for the matched shift registers by enabling the read-enable latches L2, sequentially and one at a time. In order to read out a word, the search latch L1 must be unloaded, the read-enable latch L2 must be loaded, and the sequencing latch L3 must also be loaded. Starting after the search operation, the readout st...