Magnetic bubble memory chip design

The choice and organization of bubble-circuit functions in the design of a magnetic bubble mass memory chip are discussed with emphasis on factors such as circuit function compatibility and performance, circuit density, and processing simplicity. A specific major-minor organized chip design is described which uses rotating field driven propagation, $-sign transfer gates, all T-bar minor loops, a nucleate generator with chevron merging port, a chevron based replicator/ annihilator and a chevron guard rail expander detector. The overall operating characteristics of chips having 20 510 bits of storage capacity have been measured and a bias field margin of 12 Oe is typically obtained with a 25 Oe, 100 kHz rotating field.