COMPUTER MEMORIES

A large mathematical machine must be able to store information and refer to it. This requirement has stimulated the evolution of information-storage units based on various physical effects

by Louis N. Ridenour

A computing machine capable of solving problems must possess a “memory” or, less poetically, an “information-storage unit.” The recent history of improvements in computing machines has been largely a history of improving memory devices. No ideal system has yet been found, but there has been a great deal of progress within the past decade, and several promising new developments are on the horizon.

Tiny Drum With a Big Memory
THIS 6 oz. stainless steel memory drum holds more than 10,000 bits of information recorded on its magnetic surface. Designed for airborne computers, it can hold as much information as larger, conventional drums.
Because the drum is a thin shell, most of its mass is concentrated at the surface, where it provides maximum strength and rigidity to withstand severe vibrations and shock. A lightweight frame surrounding the drum holds magnetic pickup and recording heads imbedded in rectangular blocks of plastic called slider bearings. These bearings slide over the surface of the drum on a cushion of air, staying only 100 millionths of an inch away from the drum. International Business Machines Corp., New York, designed it to withstand more than 15 times the force of gravity.