Robert M. Sandfort

Logic functions for magnetic bubble devices

An analysis has been made of the number and types of logical functions which can be performed using the interaction of circular magnetic domains in rare earth iron oxides. Multiple logic functions are found to be produced simultaneously at any logical area. These conjunctive output sets have been categorized. Several conjunctive logic gates have been designed, fabricated, and tested successfully in Sm 0.55 Tb 0.45 FeO 3 using Permalloy overlays. Utilizing a circuit in which AND/OR logic gates are coupled to a dynamic memory bank, the total correlation of two data streams has been performed. It is shown how this multiply accessed dynamic memory serves to establish the correlation threshold.

Magnetic bubble computer systems

The purpose of this paper is to extend the work presented earlier on the methods for performing logic on magnetic bubble chips, and to illustrate these techniques by presenting the outline of a design for a general-purpose digital computer.

Cascade Realizations of Magnetic Bubble Logic Using a Small Set of Primitives

Cascades of only three different primitive 3-3 magnetic bubble logic circuits are shown to realize 29 of the 31 equivalence classes of such circuits. The results are compared with earlier realizations using a set of 15 primitives.