Thin film memory
Encyclopedia
Thin-film memory is a high-speed variation of core memory developed by Sperry Rand
in a government-funded research project.
Instead of threading individual ferrite
cores on wires, thin-film memory consisted of 4 micrometre thick dots of permalloy
, an iron
-nickel
alloy, deposited on small glass plates by vacuum evaporation techniques and a mask. The drive and sense lines were then added using printed circuit
wiring over the alloy dots. This provided very fast access times in the range of 670 nanoseconds, but was very expensive to produce.
In 1962, the UNIVAC 1107
, intended for the civilian marketplace, used thin-film memory only for its 128-word general register stack. Military computers, where cost was less of a concern, used larger amounts of thin-film memory. Thin film was also used in a number of high-speed computer projects, including the high-end of the IBM
System/360
line, but general advances in core tended to keep pace.
UNIVAC
UNIVAC is the name of a business unit and division of the Remington Rand company formed by the 1950 purchase of the Eckert-Mauchly Computer Corporation, founded four years earlier by ENIAC inventors J. Presper Eckert and John Mauchly, and the associated line of computers which continues to this day...
in a government-funded research project.
Instead of threading individual ferrite
Ferrite (magnet)
Ferrites are chemical compounds consisting of ceramic materials with iron oxide as their principal component. Many of them are magnetic materials and they are used to make permanent magnets, ferrite cores for transformers, and in various other applications.Many ferrites are spinels with the...
cores on wires, thin-film memory consisted of 4 micrometre thick dots of permalloy
Permalloy
Permalloy is a nickel-iron magnetic alloy, with about 20% iron and 80% nickel content. It is notable for its very high magnetic permeability, which makes it useful as a magnetic core material in electrical and electronic equipment, and also in magnetic shielding to block magnetic fields...
, an iron
Iron
Iron is a chemical element with the symbol Fe and atomic number 26. It is a metal in the first transition series. It is the most common element forming the planet Earth as a whole, forming much of Earth's outer and inner core. It is the fourth most common element in the Earth's crust...
-nickel
Nickel
Nickel is a chemical element with the chemical symbol Ni and atomic number 28. It is a silvery-white lustrous metal with a slight golden tinge. Nickel belongs to the transition metals and is hard and ductile...
alloy, deposited on small glass plates by vacuum evaporation techniques and a mask. The drive and sense lines were then added using printed circuit
Printed circuit
Printed circuit may refer to:* Printed circuit board* Printed Circuit Corporation, an electronics manufacturer...
wiring over the alloy dots. This provided very fast access times in the range of 670 nanoseconds, but was very expensive to produce.
In 1962, the UNIVAC 1107
UNIVAC 1107
The UNIVAC 1107 was the first member of Sperry Rand's UNIVAC 1100 series of computers, introduced in October 1962. It was also known as the Thin Film Computer because of its use of thin film memory for its register storage...
, intended for the civilian marketplace, used thin-film memory only for its 128-word general register stack. Military computers, where cost was less of a concern, used larger amounts of thin-film memory. Thin film was also used in a number of high-speed computer projects, including the high-end of the IBM
IBM
International Business Machines Corporation or IBM is an American multinational technology and consulting corporation headquartered in Armonk, New York, United States. IBM manufactures and sells computer hardware and software, and it offers infrastructure, hosting and consulting services in areas...
System/360
System/360
The IBM System/360 was a mainframe computer system family first announced by IBM on April 7, 1964, and sold between 1964 and 1978. It was the first family of computers designed to cover the complete range of applications, from small to large, both commercial and scientific...
line, but general advances in core tended to keep pace.