Magnetic bubble repertory dialer memory

A 3648-bit memory, based on bubble technology, has been designed and constructed. This moderately high-density design, 600 bit/mm², serves as a test vehicle for proposed mass memories. The series-parallel organization utilizes 38 transfer gates that are simultaneously activated by reverse rotation of the drive field. Forty-eight words of 76 bits each can be stored and randomly accessed. The storage medium is Gd2.34,Tb0.66Fe5O12, and T-bar propagating circuits are used. The design and operation of the memory is described. The operating margins are given. Underlying design principles and criteria for propagating circuits have evolved and are presented.