Plated wire memory
Encyclopedia
Plated wire memory is a variation of core memory developed by Bell Laboratories in 1957. Its primary advantage was that it could be machine-assembled, which potentially led to lower prices than the hand-assembled core.
Instead of threading individual ferrite
cores on wires, plated wire memory used a grid of wires coated with a thin layer of iron
-nickel
alloy (called permalloy
). The magnetic field normally stored in the ferrite core was instead stored on the wire itself. Operation was generally similar to core, but could also be built with a non-destructive read that did not require refreshing.
Plated wire memory has been used in a number of applications, typically in aerospace
. It was used in the UNIVAC 1110
and UNIVAC 9000-series computers, the Viking program
that sent landers to Mars
, a prototype guidance computer for the Minuteman-III, the Space Shuttle Main Engine Controllers, KH-9 Hexagon reconnaissance satellite and in the Hubble Space Telescope
.
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, plated wire memory used a grid of wires coated with a thin layer of 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 (called 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...
). The magnetic field normally stored in the ferrite core was instead stored on the wire itself. Operation was generally similar to core, but could also be built with a non-destructive read that did not require refreshing.
Plated wire memory has been used in a number of applications, typically in aerospace
Aerospace
Aerospace comprises the atmosphere of Earth and surrounding space. Typically the term is used to refer to the industry that researches, designs, manufactures, operates, and maintains vehicles moving through air and space...
. It was used in the UNIVAC 1110
UNIVAC 1110
The UNIVAC 1110 was the fourth member of Sperry Rand's UNIVAC 1100 series of computers, introduced in 1972.The UNIVAC 1110 had enhanced multiprocessing support: sixteen-way memory access allowed up to six CAUs and four IOAUs The UNIVAC 1110 was the fourth member of Sperry Rand's UNIVAC 1100 series...
and UNIVAC 9000-series computers, the Viking program
Viking program
The Viking program consisted of a pair of American space probes sent to Mars, Viking 1 and Viking 2. Each spacecraft was composed of two main parts, an orbiter designed to photograph the surface of Mars from orbit, and a lander designed to study the planet from the surface...
that sent landers to Mars
Mars
Mars is the fourth planet from the Sun in the Solar System. The planet is named after the Roman god of war, Mars. It is often described as the "Red Planet", as the iron oxide prevalent on its surface gives it a reddish appearance...
, a prototype guidance computer for the Minuteman-III, the Space Shuttle Main Engine Controllers, KH-9 Hexagon reconnaissance satellite and in the Hubble Space Telescope
Hubble Space Telescope
The Hubble Space Telescope is a space telescope that was carried into orbit by a Space Shuttle in 1990 and remains in operation. A 2.4 meter aperture telescope in low Earth orbit, Hubble's four main instruments observe in the near ultraviolet, visible, and near infrared...
.