Bell Telephone Laboratories: New Twist in Memory Devices
February 1958 Radio & TV News

February 1958 Radio & TV News

[Table of Contents] Wax nostalgic about and learn from the history of early electronics. See articles from Radio & Television News, published 1919-1959. All copyrights hereby acknowledged.

Upon seeing this advertisement by Bell Laboratories for their "Twistor" form of magnetic memory data storage in a 1958 issue of Radio News magazine, my thought was that it was just another flash in the pan, so to speak, in the history of breakthrough, paradigm-changing inventions. It was a variation of the non-volatile magnetic core memory that used sections of ferromagnetic wire twisted around copper wire in such a way that electrical currents directed to particular intersections in an x-y grid would cause a magnetic orientation to be set (store a bit) and a set or read and sense wires permitted detection of the stored magnetic field to be determined (read a bit). The Twistor was hailed as a much more manufacturable form of the magnetic core memory, which required production workers with small hands and finger to manually thread the x, y, read, and sense wires through a matrix of miniature magnetic cores. Western Electric, the primary manufacturing company for Bell Telephone (look at who made your old dial and pushbutton phones), actually built an entire system in the mid 1960s dubbed the Number One Electronic Switching System (1ESS) around the Twistor. The Wikipedia entry for the Twistor says the device was first introduced in 1957.

Bell Telephone Laboratories: 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.

"Twistor" 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 27, 2020