IBM Core Threading Machine

Many people wonder how core memory was threaded, since it's so ridiculously tiny and has so many wires. The common lore is that Japanese girls did it by hand with tweezers and infinite patience.

An old computer book, IBM's Early Computers by C.J. Bashe, L.R. Johnson, J.H. Palmer and E.W. Pugh (Cambridge:MIT Press, 1986), gives the lie to that notion. U.S. patents 2958126 and 3134163, among others, are associated with this machine. From page 268 of the book:

Figure 7.4

Core threading machine. The vacuum matrix and covers (top) hold an array of 128 X 128 cores in place ready for wiring. The sixty-four needles to the right have been withdrawn, leaving the sixty-four wires threaded through the cores. After these wires are attached to the terminals on the edge of the core plane, the needle feeder is indexed to the left to insert the adjacent group of sixty-four wires. The array is then rotated 90 degrees to permit the orthogonal wires to be similarly threaded. Needles of the wiring machine are shown (bottom) passing through the cores and over orthogonal wires previously inserted. The cores have an inside diameter of 30 mil and outside diameter of 50 mil. When first introduced in 1959, this core threading machine reduced the time to thread X and Y wires in a 64 X 64 plane from 25 hours to 12 minutes.

Page created 11/30/08 by DF