Plated-wire memory is a variation of

core memory Core or cores may refer to: Science and technology * Core (anatomy), everything except the appendages * Core (manufacturing), used in casting and molding * Core (optical fiber), the signal-carrying portion of an optical fiber * Core, the central ...

developed by

Bell Laboratories Nokia Bell Labs, originally named Bell Telephone Laboratories (1925–1984), then AT&T Bell Laboratories (1984–1996) and Bell Labs Innovations (1996–2007), is an American industrial research and scientific development company owned by mult ...

in 1957. Its primary advantage was that it could be machine-assembled, which potentially led to lower prices than the almost always 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 Iron () is a chemical element with symbol Fe (from la, ferrum) 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, right in f ...

–

nickel Nickel is a chemical element with 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 slow to ...

alloy called

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 as a ...

. 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, enterpris ...

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 astrona ...

. 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'', which landed on Mars in 1976. Each spacecraft was composed of two main parts: an orbiter designed to photograph the surface of Mars f ...

that sent landers to

Mars Mars is the fourth planet from the Sun and the second-smallest planet in the Solar System, only being larger than Mercury (planet), Mercury. In the English language, Mars is named for the Mars (mythology), Roman god of war. Mars is a terr ...

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

KH-9 Hexagon KH-9 ( 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 attempts by the National Reco ...

reconnaissance satellite, and in the

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

References

External links

technikum29.de - Description of Plated-wire memory
Computer memory Non-volatile memory {{compu-hardware-stub