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Thin Film Memory
Thin-film memory is a high-speed alternative to magnetic-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-micrometer 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 The IBM System/360 (S/360) is a family of mainframe computer systems announced by IBM ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 magnetic material (usually a Ferrite (magnet)#Semi-hard ferrites, semi-hard ferrite). Each core stores one bit of information. Two or more wires pass through each core, forming an X-Y array of cores. When an electrical current above a certain threshold is applied to the wires, the core will become magnetized. The core to be assigned a value – or ''written'' – is selected by powering one X and one Y wire to half of the required current, such that only the single core at the intersection is written. Depending on the direction of the currents, the core will pick up a clockwise or counterclockwise magnetic field, storing a 1 or 0. This writing process also causes electricity to be electromagnetic induction, induced into nearby wires. If t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sperry Corporation
Sperry Corporation was a major American equipment and electronics company whose existence spanned more than seven decades of the 20th century. Sperry ceased to exist in 1986 following a prolonged hostile takeover bid engineered by Burroughs Corporation, which merged the combined operation under the new name Unisys. Some of Sperry's former divisions became part of Honeywell, Lockheed Martin, Raytheon Technologies, and Northrop Grumman. The company is best known as the developer of the artificial horizon and a wide variety of other gyroscope-based aviation instruments like autopilots, bombsights, analog ballistics computers and gyro gunsights. In the post-WWII era the company branched out into electronics, both aviation-related, and later, computers. The company was founded by Elmer Ambrose Sperry. History Early history The company was incorporated on April 14 1910 by Elmer Ambrose Sperry as the Sperry Gyroscope Company, to manufacture navigation equipment—chief ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ferrite (magnet)
A ferrite is one of a family of iron oxide-containing magnetic ceramic materials. They are ferrimagnetic, meaning they are attracted by magnetic fields and can be Magnetization, magnetized to become permanent magnets. Unlike many ferromagnetic materials, most ferrites are not electrically electrical conductor, conductive, making them useful in applications like magnetic cores for transformers to suppress eddy currents. Ferrites can be divided into two groups based on their magnetic coercivity, their resistance to being demagnetized: "Hard" ferrites have high coercivity, so are difficult to demagnetize. They are used to make permanent magnets for applications such as refrigerator magnets, loudspeakers, and small electric motors. "Soft" ferrites have low coercivity, so they easily change their magnetization and act as conductors of magnetic fields. They are used in the electronics industry to make efficient magnetic cores called ferrite cores for high-frequency inductors, transfo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 magnetic core material in electrical and electronic equipment, and also in magnetic shielding to block magnetic fields. Commercial permalloy alloys typically have relative permeability of around 100,000, compared to several thousand for ordinary steel. In addition to high permeability, its other magnetic properties are low coercivity, near zero magnetostriction, and significant anisotropic magnetoresistance. The low magnetostriction is critical for industrial applications, allowing it to be used in thin films where variable stresses would otherwise cause a ruinously large variation in magnetic properties. Permalloy's electrical resistivity can vary as much as 5% depending on the strength and the direction of an applied magnetic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 outer and inner core. It is the fourth most abundant element in the Earth's crust, being mainly deposited by meteorites in its metallic state. Extracting usable metal from iron ores requires kilns or furnaces capable of reaching , about 500 °C (900 °F) higher than that required to smelt copper. Humans started to master that process in Eurasia during the 2nd millennium BC and the use of iron tools and weapons began to displace copper alloys – in some regions, only around 1200 BC. That event is considered the transition from the Bronze Age to the Iron Age. In the modern world, iron alloys, such as steel, stainless steel, cast iron and special steels, are by far the most common industrial metals, due to their mechan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 slow to react with air under standard conditions because a passivation layer of nickel oxide forms on the surface that prevents further corrosion. Even so, pure native nickel is found in Earth's crust only in tiny amounts, usually in ultramafic rocks, and in the interiors of larger nickel–iron meteorites that were not exposed to oxygen when outside Earth's atmosphere. Meteoric nickel is found in combination with iron, a reflection of the origin of those elements as major end products of supernova nucleosynthesis. An iron–nickel mixture is thought to compose Earth's outer and inner cores. Use of nickel (as natural meteoric nickel–iron alloy) has been traced as far back as 3500 BCE. Nickel was first isolated and classifie ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Printed Circuit
A printed circuit board (PCB), also called printed wiring board (PWB), is a laminated sandwich structure of conductive and insulating layers, each with a pattern of traces, planes and other features (similar to wires on a flat surface) etched from one or more sheet layers of copper laminated onto or between sheet layers of a non-conductive substrate. PCBs are used to connect or "wire" components to one another in an electronic circuit. Electrical components may be fixed to conductive pads on the outer layers, generally by soldering, which both electrically connects and mechanically fastens the components to the board. Another manufacturing process adds vias, metal-lined drilled holes that enable electrical interconnections between conductive layers, to boards with more than a single side. Printed circuit boards are used in nearly all electronic products today. Alternatives to PCBs include wire wrap and point-to-point construction, both once popular but now rarely ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
UNIVAC 1107
The UNIVAC 1100/2200 series is a series of compatible 36-bit computer systems, beginning with the UNIVAC 1107 in 1962, initially made by Sperry Rand. The series continues to be supported today by Unisys Corporation as the ClearPath Dorado Series. The solid-state 1107 model number was in the same sequence as the earlier vacuum-tube computers, but the early computers were not compatible with their solid-state successors. Architecture Data formats * Fixed-point, either integer or fraction **Whole word – 36-bit (ones' complement) **Half word – two 18-bit fields per word (unsigned or ones' complement) **Third word – three 12-bit fields per word (ones' complement) **Quarter word – four 9-bit fields per word (unsigned) **Sixth word – six 6-bit fields per word (unsigned) * Floating point **Single precision – 36 bits: sign bit, 8-bit characteristic, 27-bit mantissa **Double precision – 72 bits: sign bit, 11-bit characteristic, 60-bit mantissa *Alphanumeric ** FIELDATA � ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Military Computer
This article specifically addresses U.S. armed forces military computers and their use. History Some of the earliest computers were military computers. Military requirements for portability and ruggedness led to some of the earliest transistorized computers, such as the 1958 AN/USQ-17, the 1959 AN/MYK-1 ( MOBIDIC), the 1960 M18 FADAC, and the 1962 D-17B; the earliest integrated-circuit based computer, the 1964 D-37C; as well as one of the earliest laptop computers, the 1982 Grid Compass. Military requirements for a computer small enough to fit through a submarine's hatch led to the AN/UYK-1. Construction Typically a military computer is much more robust than an industrial computer enclosure. Most electronics will be protected with a layer of conformal coating. There will be more structure inside to support the components, the plug-in cards will be individually supported and secured to assure they do not pop out of their sockets, the processor and heat sink will be secur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
System/360
The IBM System/360 (S/360) is a family of mainframe computer systems announced by IBM on April 7, 1964, and delivered between 1965 and 1978. System/360 was the first family of computers designed to cover both commercial and scientific applications and a complete range of applications from small to large. The design distinguished between computer architecture, architecture and implementation, allowing IBM to release a suite of compatible designs at different prices. All but the only partially compatible IBM System/360 Model 44, Model 44 and the most expensive systems use microcode to implement the instruction set, featuring 8-bit computing, 8-bit byte addressing and fixed-point binary, fixed-point decimal and IBM hexadecimal floating-point, hexadecimal floating-point arithmetic, floating-point calculations. The System/360 family introduced IBM's Solid Logic Technology (SLT), which packed more transistors onto a circuit card, allowing more powerful but smaller computers. System/36 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Computer Memory
Computer memory stores information, such as data and programs, for immediate use in the computer. The term ''memory'' is often synonymous with the terms ''RAM,'' ''main memory,'' or ''primary storage.'' Archaic synonyms for main memory include ''core'' (for magnetic core memory) and ''store''. Main memory operates at a high speed compared to mass storage which is slower but less expensive per bit and higher in capacity. Besides storing opened programs and data being actively processed, computer memory serves as a Page cache, mass storage cache and write buffer to improve both reading and writing performance. Operating systems borrow RAM capacity for caching so long as it is not needed by running software. If needed, contents of the computer memory can be transferred to storage; a common way of doing this is through a memory management technique called ''virtual memory''. Modern computer memory is implemented as semiconductor memory, where data is stored within memory cell (com ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Non-volatile Memory
Non-volatile memory (NVM) or non-volatile storage is a type of computer memory that can retain stored information even after power is removed. In contrast, volatile memory needs constant power in order to retain data. Non-volatile memory typically refers to storage in memory chips, which store data in floating-gate memory cells consisting of floating-gate MOSFETs ( metal–oxide–semiconductor field-effect transistors), including flash memory storage such as NAND flash and solid-state drives (SSD). Other examples of non-volatile memory include read-only memory (ROM), EPROM (erasable programmable ROM) and EEPROM (electrically erasable programmable ROM), ferroelectric RAM, most types of computer data storage devices (e.g. disk storage, hard disk drives, optical discs, floppy disks, and magnetic tape), and early computer storage methods such as punched tape and cards. Overview Non-volatile memory is typically used for the task of secondary storage or long-term per ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
