Feasibility model of a 107bit magnetic-film memory

A partially populated model of a 10-million-bit magnetic-film memory was tested at 0.36 μs access time and 0.9-μs cycle time. The integral word conductor enclosed by magnetic film was formed by evaporation and plating with 200 000 bit on each substrate. Digit lines were made by laminating sheet copper onto 50-in long glass substrates and scribing into lines. The use of rigid substrates for both the word and digit lines gave low parasitic noise. The design required a keepered digit line; several different configurations were demonstrated to provide adequate closure. Cost per bit was reduced from an earlier design through sharing of the sense circuit by 32 000 bit and simplification of the digit line balance circuit.