New Twist in Memory Devices
February 1958 Radio Electronics Article

February 1958 Radio-Electronics

February 1958 Radio-Electronics Cover - RF Cafe[Table of Contents]

Wax nostalgic about and learn from the history of early electronics. See articles from Radio-Electronics, published 1929 - 1948. All copyrights hereby acknowledged.

In another blast from the past, I just found an advertisement by Bell Telephone Laboratories announcing "Twistor" memory in a 1958 edition of Radio-Electronics. According to Bell, their radically new "Twistor" magnetic memory matrix was vastly superior to conventional ferrite core memories. It used hair-thin magnetic wires (more like a flattened tape) interwoven with equally thin copper wires to store and read out ones and zeroes. Doing so reduced manufacturing costs, by eliminating the relatively expensive ferrite cores and eliminating the difficult job of threading the read, write, and sense wires through the core centers. Twistor memory also required less current to operate, was denser, and weighed less than core memory. Within a decade CMOS RAM was available to replace the magnetic memory, but from a reliability standpoint, the Apollo space program selected magnetic core memory for the manned flights.

New Twist in Memory Devices

Model (simplified) illustrates basic structure of magnetic "Twistor" memory-magnetic and copper wires interwoven as in a window screen. Twisted condition of the magnetic wire shifts preferred direction of magnetization from a longitudinal to a helical path. One inch of twisted wire, thinner than a hair, can store as much information as ten ferrite rings. "Twistor" was invented at Bell Laboratories by Andrew Bobeck, M.S. in E.E. from Purdue University.

An ingenious new kind of magnetic memory has been developed by Bell Laboratories scientists for the storage of digital information. Known as the "Twistor ," it consists basically of copper wires interwoven with magnetic wires to form a grid.

"Twister" gets its name from a characteristic of wire made of magnetic material. Torsion applied to such a wire shifts the preferred direction of magnetization from a longitudinal to a helical path. This helical magnetization has been applied to produce a magnetic storage device of unprecedented capacity for its size.

In a magnetic memory, information is stored by magnetizing a storage element. In conventional memories the storage elements consist of rings of ferrite. In the "Twistor," they consist of tiny segments of hair-thin magnetic wire. At each intersection of the grid, one such segment is capable of storing a binary digit.

The "Twistor" is simple and economical to fabricate, and its minute energy requirements are easily supplied by transistor circuits. Bell Laboratories engineers see important uses for it in future telephone systems which demand the compact storage of much information, as well as in digital computers for civilian and military applications.

Bell Telephone Laboratories World Center of Communications Research and Development

Posted  January 14, 2014