Swap and replicate gates for magnetic bubble memory

Abstract

Input swap transfer/replicate gate and output replicate gate for use in a magnetic bubble memory arrangement between the bubble storage loops and the input and output sections respectively on opposite sides thereof. The input swap transfer/replicate gate and the output replicate gate are of double level construction, each type of gate including a hairpin element at the first level and mounted on a planar layer of bubble-supporting magnetic material on which bubble propagation elements of magnetically soft material are disposed. The bubble propagation elements are arranged to form propagation paths defining a bubble input section, a bubble output section, and a plurality of closed storage loops defining a bubble storage section interposed between the input and output bubble sections. The second levels of the swap transfer/replicate gate and output replicate gate are situated at the input and output ends of the storage loops, forming the opposite bights of the loop. Each type of gate at the second level comprises an asymmetric hook-like transfer/replicate element whose opposite ends are respectively disposed in the opposite courses of the storage loop of which it forms a bight. The hook-like element includes an intermediate leg portion thereof disposed in overlapping relation to the loop region of the hairpin element, the intermediate leg portion being of wedge-shaped configuration and tapering toward the leading end of the asymmetric hook-like transfer element so as to have a reduced width dimension at the leading end thereof. The wedge-shaped configuration of the intermediate leg of the asymmetric hook-like element is responsible for greater reliability in data transfer and replication as represented by bubbles and the absence of bubbles into and out of the storage loops of the magnetic bubble memory organization.