Operating Characteristics of a Thin Film Memory

An experimental prototype memory with 32 ten bit words has been designed, built, and tested. Circular spots $\frac{1}{16}\hspace{0.17em}\mathrm{in.}$ in diameter about 600 A thick are used. These are evaporated on two pieces of glass each comprising a $\text{16×16}$ spot array. An operating cycle time of less than one‐half microsecond appears possible. The circuitry for driving and sensing is transistorized and the memory uses external register selection from a core‐diode matrix. Word selection is provided by a transverse field, and a digit winding conditions the information written by applying a longitudinal field in the “one” or “zero” direction. Extension to sizes of the order of 1000 words is planned using these techniques. The memory constructed here will soon be installed in the control element of the TX‐2 computer.