IBM 2361 core storage unit

The 2361 was introduced by IBM in 1964.

The 2361 was introduced by IBM in 1964.
The IBM 2361, built by IBM's Poughkeepsie, N.Y. manufacturing facilities, was installed at NASA's Manned Spacecraft Center (MSC) in Houston, Texas, to process vast quantities of information used by MSC-based flight controllers for the Gemini and Apollo missions. These units had 16 times the capacity of any previous IBM memory.

In each 2361, almost 20 million ferrite cores -- tiny doughnut-shaped objects, each about the size of a pinhead -- were strung in two-wire networks and packaged, with associated circuitry, into a cabinet only five by 2 ½ feet and less than six feet tall. The first memory was installed for use in a complex of five powerful IBM 7094 Model II data processing systems. Four additional memories were added to the NASA Real Time Computer Complex (RTCC).

The 2361's design provided for storage of 524,000 36-bit words and a total cycle time of eight microseconds in each memory. The 2361 was the first IBM memory to use two-wire core storage to increase storage capacity, improve performance and reduce unit size.

Cores were woven into each juncture of a screen-like mesh of wire to form a plane resembling a small window screen. Memory circuits were associated with core planes in the 2361 and included some 3,500 Solid Logic Technology modules and 35,000 high-current silicon diodes. Major feats in fabricating the 2361 included soldering and testing 180,000 connections, and welding and testing another 180,000 connections.