Plated-wire memory is a variation of

magnetic-core memory In computing, magnetic-core memory is a form of random-access memory. It predominated for roughly 20 years between 1955 and 1975, and is often just called core memory, or, informally, core. Core memory uses toroids (rings) of a hard magneti ...

developed by

Bell Laboratories Nokia Bell Labs, commonly referred to as ''Bell Labs'', is an American industrial research and development company owned by Finnish technology company Nokia. With headquarters located in Murray Hill, New Jersey, the company operates several lab ...

in 1957. Its primary advantage was that it could be assembled by machine, which potentially led to lower prices than magnetic core, which was almost always assembled by hand. Instead of threading individual ferrite cores on wires, plated-wire memory used a grid of wires coated with a thin layer of

iron Iron is a chemical element; it has symbol Fe () and atomic number 26. It is a metal that belongs to the first transition series and group 8 of the periodic table. It is, by mass, the most common element on Earth, forming much of Earth's o ...

–

nickel Nickel is a chemical element; it has symbol Ni and atomic number 28. It is a silvery-white lustrous metal with a slight golden tinge. Nickel is a hard and ductile transition metal. Pure nickel is chemically reactive, but large pieces are slo ...

alloy (

permalloy Permalloy () is a nickel–iron magnetic alloy, with about 80% nickel and 20% iron content. Invented in 1914 by physicist Gustav Elmen at Bell Telephone Laboratories, it is notable for its very high magnetic permeability, which makes it useful ...

). The magnetic field normally stored in the ferrite core was instead stored on the wire itself. Operation was generally similar to core memory, with the wire itself acting as the data line, and the magnetic domains providing the individual bit locations defined by address (word) lines running on either side of (and perpendicular to) the data wire. Early versions operated in a destructive read mode, requiring a write after read to restore data. Non-destructive read mode was possible, but this required much greater uniformity of the magnetic coating. Improvements in semiconductor RAM chips provided the higher storage densities and higher speeds needed for large-scale application such as

mainframe computer A mainframe computer, informally called a mainframe or big iron, is a computer used primarily by large organizations for critical applications like bulk data processing for tasks such as censuses, industry and consumer statistics, enterprise ...

s, replacing previous types of memory, including both core and plated-wire memory. Plated-wire memory has been used in a number of applications, typically in

aerospace Aerospace is a term used to collectively refer to the atmosphere and outer space. Aerospace activity is very diverse, with a multitude of commercial, industrial, and military applications. Aerospace engineering consists of aeronautics and astron ...

. It was used in the UNIVAC 1110 and UNIVAC 9000 series computers, the

Viking program The ''Viking'' program consisted of a pair of identical American space probes, ''Viking 1'' and ''Viking 2'' both launched in 1975, and landed on Mars in 1976. The mission effort began in 1968 and was managed by the NASA Langley Research Cent ...

that sent landers to

Mars Mars is the fourth planet from the Sun. It is also known as the "Red Planet", because of its orange-red appearance. Mars is a desert-like rocky planet with a tenuous carbon dioxide () atmosphere. At the average surface level the atmosph ...

, the

Voyager Voyager may refer to: Computing and communications * LG Voyager, a mobile phone model manufactured by LG Electronics * NCR Voyager, a computer platform produced by NCR Corporation * Voyager (computer worm), a computer worm affecting Oracle ...

space probes, a prototype guidance computer for the Minuteman-III, the Space Shuttle Main Engine controllers, the

KH-9 Hexagon KH-9 (Byeman Control System, BYEMAN codename HEXAGON), commonly known as Big Bird or KeyHole-9, p.32 Big Bird was a series of photographic reconnaissance satellites launched by the United States between 1971 and 1986. Of twenty launch attempt ...

reconnaissance satellite, and in the

Hubble Space Telescope The Hubble Space Telescope (HST or Hubble) is a space telescope that was launched into low Earth orbit in 1990 and remains in operation. It was not the Orbiting Solar Observatory, first space telescope, but it is one of the largest and most ...

References

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External links

technikum29.de - Description of Plated-wire memory
Computer memory Non-volatile memory