HOME TheInfoList.com
Providing Lists of Related Topics to Help You Find Great Stuff

picture info

Magnetic-core Memory
Magnetic-core memory
Magnetic-core memory
was the predominant form of random-access computer memory for 20 years between about 1955 and 1975. Such memory is often just called core memory, or, informally, core. Core uses tiny magnetic toroids (rings), the cores, through which wires are threaded to write and read information. Each core represents one bit of information. The cores can be magnetized in two different ways (clockwise or counterclockwise) and the bit stored in a core is zero or one depending on that core's magnetization direction. The wires are arranged to allow for an individual core to be set to either a one or a zero and for its magnetization to be changed by sending appropriate electric current pulses through selected wires. The process of reading the core causes the core to be reset to a zero, thus erasing it. This is called destructive readout
[...More...]

Core Memory (other)
Core memory
Core memory
or magnetic-core memory, is a form of random access computer memory used by computers in the mid-20th century. Core Memory or core memory may also refer to:Core memories, plot-critical items in the 2005 video game Star Fox Assault Core Memories, plot-critical items in the 2015 animated film Inside OutThis disambiguation page lists articles associated with the title Core memory. If an internal link led you here, you may wish to change the link to point directly to the inten
[...More...]

picture info

Optical Disc
In computing and optical disc recording technologies, an optical disc (OD) is a flat, usually circular disc which encodes binary data (bits) in the form of pits (binary value of 0 or off, due to lack of reflection when read) and lands (binary value of 1 or on, due to a reflection when read) on a special material (often aluminium[1] ) on one of its flat surfaces. The encoding material sits atop a thicker substrate (usually polycarbonate) which makes up the bulk of the disc and forms a dust defocusing layer. The encoding pattern follows a continuous, spiral path covering the entire disc surface and extending from the innermost track to the outermost track
[...More...]

Memory Density
Areal density is a measure of the quantity of information bits that can be stored on a given length of track, area of surface, or in a given volume of a computer storage medium. Generally, higher density is more desirable, for it allows greater volumes of data to be stored in the same physical space. Density therefore has a direct relationship to storage capacity of a given medium. Density also generally has a fairly direct effect on the performance within a particular medium, as well as price.Contents1 Storage device classes1.1 Magnetic disk media 1.2 Optical disc media 1.3 Magnetic tape media2 Research 3 Effects on performance 4 Effects on price 5 See also 6 ReferencesStorage device classes[edit] Magnetic disk media[edit] Hard disk
Hard disk
drives store data in the magnetic polarization of small patches of the surface coating on a disk
[...More...]

picture info

Electric Current
An electric current is a flow of electric charge.[1]:2 In electric circuits this charge is often carried by moving electrons in a wire. It can also be carried by ions in an electrolyte, or by both ions and electrons such as in an ionised gas (plasma).[2] The SI unit
SI unit
for measuring an electric current is the ampere, which is the flow of electric charge across a surface at the rate of one coulomb per second. Electric current
Electric current
is measured using a device called an ammeter.[3] Electric currents cause Joule
Joule
heating, which creates light in incandescent light bulbs. They also create magnetic fields, which are used in motors, inductors and generators. The moving charged particles in an electric current are called charge carriers. In metals, one or more electrons from each atom are loosely bound to the atom, and can move freely about within the metal
[...More...]

picture info

Bit
The bit (a portmanteau of binary digit)[1] is a basic unit of information used in computing and digital communications. A binary digit can have only one of two values, and may be physically represented with a two-state device. These state values are most commonly represented as either a 0or1. The two values of a binary digit can also be interpreted as logical values (true/false, yes/no), algebraic signs (+/−), activation states (on/off), or any other two-valued attribute. The correspondence between these values and the physical states of the underlying storage or device is a matter of convention, and different assignments may be used even within the same device or program
[...More...]

picture info

Toroid
In mathematics, a toroid is a surface of revolution with a hole in the middle, like a doughnut, forming a solid body. The axis of revolution passes through the hole and so does not intersect the surface.[1] For example, when a rectangle is rotated around an axis parallel to one of its edges, then a hollow rectangle-section ring is produced. If the revolved figure is a circle, then the object is called a torus. The term toroid is also used to describe a toroidal polyhedron. In this context a toroid need not be circular and may have any number of holes. A g-holed toroid can be seen as approximating the surface of a torus having a topological genus, g, of 1 or greater. The Euler characteristic χ of a g holed toroid is 2(1-g).[2] A toroid is specified by the radius of revolution R measured from the center of the section rotated
[...More...]

picture info

Random Access
In computer science, random access (more precisely and more generally called direct access) is the ability to access any item of data from a population of addressable elements roughly as easily and efficiently as any other, no matter how many elements may be in the set. It is typically contrasted to sequential access. For example, data might be stored notionally in a single sequence like a row, in two dimensions like rows and columns on a surface, or in multiple dimensions. However, given all the coordinates, a program can access each record about as quickly and easily as any other. In this sense the choice of data item is arbitrary in the sense that no matter which item is sought, all that is needed to find it, is its address, that is to say, the coordinates at which it is located, such as its row and column (or its track and record number on a magnetic drum)
[...More...]

picture info

Disk Pack
Disk packs and disk cartridges were early forms of removable media for computer data storage, introduced in the 1960s.Contents1 Disk pack 2 Disk cartridge 3 Alignment 4 References 5 See alsoDisk pack[edit] Disk pack
Disk pack
manufactured by Nashua, USA, without its protective cover. A 3.5" modern hard drive is shown for comparison.A Disk pack
Disk pack
is a layered grouping of hard disk platters (circular, rigid discs coated with a magnetic data storage surface). A disk pack is the core component of a hard disk drive. In modern hard disks, the disk pack is permanently sealed inside the drive. In many early hard disks, the disk pack was a removable unit, and would be supplied with a protective canister featuring a lifting handle. The protective cover consisted of two parts, a clear plastic shell, with a handle in the center, that enclosed the top and sides of the disks and a separate bottom that completed the sealed package
[...More...]

Paper Data Storage
Paper
Paper
data storage refers to the use of paper as a data storage device. This includes writing, illustrating, and the use of data that can be interpreted by a machine or is the result of the functioning of a machine. A defining feature of paper data storage is the ability of humans to produce it with only simple tools and interpret it visually. Though this is now mostly obsolete, paper was once also an important form of computer data storage.Contents1 History 2 Limits 3 See also 4 References 5 External linksHistory[edit] Before paper was used for storing data, it had been used in several applications for storing instructions to specify a machine's operation. The earliest use of paper to store instructions for a machine was the work of Basile Bouchon
Basile Bouchon
who, in 1725, used punched paper rolls to control textile looms. This technology was later developed into the wildly successful Jacquard loom
[...More...]

Core Dump
In computing, a core dump, memory dump, or system dump[1] consists of the recorded state of the working memory of a computer program at a specific time, generally when the program has crashed or otherwise terminated abnormally.[2] In practice, other key pieces of program state are usually dumped at the same time, including the processor registers, which may include the program counter and stack pointer, memory management information, and other processor and operating system flags and information. Core dumps are often used to assist in diagnosing and debugging errors in computer programs. The name comes from magnetic core memory,[3] the principal form of random access memory from the 1950s to the 1970s
[...More...]

picture info

Dekatron
In electronics, a Dekatron
Dekatron
(or Decatron, or generically three-phase gas counting tube or glow-transfer counting tube or cold cathode tube) is a gas-filled decade counting tube. Dekatrons were used in computers, calculators and other counting-related products during the 1950s and 1960s. "Dekatron," now a generic trademark, was the brand name used by Ericsson Telephones Limited (ETL), of Beeston, Nottingham (not to be confused with the Swedish TelefonAB Ericsson
Ericsson
of Stockholm).A dekatron in operation.The dekatron was useful for computing, calculating and frequency-dividing purposes because one complete revolution of the neon dot in a dekatron means 10 pulses on the guide electrode(s), and a signal can be derived from one of the ten cathodes in a dekatron to send a pulse, possibly for another counting stage
[...More...]

Mellon Optical Memory
Mellon optical memory was an early form of computer memory invented at the Mellon Institute
Mellon Institute
(today part of Carnegie Mellon University) in 1951.[1][2] The device used a combination of photoemissive and phosphorescent materials to produce a "light loop" between two surfaces. The presence or lack of light, detected by a photocell, represented a one or zero. Although promising, the system was rendered obsolete with the introduction of core memory in the early 1950s. It appears that the system was never used in production.Contents1 Description1.1 Writing 1.2 Reading2 ReferencesDescription[edit] The main memory element of the Mellon device consisted of a very large (television sized) square vacuum tube consisting of two slightly separated flat glass plates. The inner side of one of the plates was coated with a photoemissive material that released electrons when struck by light
[...More...]

picture info

Hard Disk Drive
A hard disk drive (HDD), hard disk, hard drive or fixed disk[b] is a data storage device that uses magnetic storage to store and retrieve digital information using one or more rigid rapidly rotating disks (platters) coated with magnetic material. The platters are paired with magnetic heads, usually arranged on a moving actuator arm, which read and write data to the platter surfaces.[2] Data is accessed in a random-access manner, meaning that individual blocks of data can be stored or retrieved in any order and not only sequentially. HDDs are a type of non-volatile storage, retaining stored data even when powered off.[3][4][5] Introduced by IBM
IBM
in 1956,[6] HDDs became the dominant secondary storage device for general-purpose computers by the early 1960s. Continuously improved, HDDs have maintained this position into the modern era of servers and personal computers
[...More...]

picture info

Intel 1103
The 1103 is a dynamic random-access memory (DRAM) integrated circuit (IC) developed and fabricated by Intel. Introduced in October 1970, the 1103 was the first commercially available DRAM IC; and due to its small physical size and low price relative to magnetic-core memory, it replaced the latter in many applications.[3][1] While it was introduced in 1970, initial production yields were poor, and it was not until the fifth stepping of the production masks that it became available in large quantities during 1971. Development[edit] In 1969 William Regitz and his colleagues at Honeywell
Honeywell
invented a three-transistor dynamic memory cell and began to canvass the semiconductor industry for a producer
[...More...]

picture info

Magnetic Tape
Magnetic tape
Magnetic tape
is a medium for magnetic recording, made of a thin, magnetizable coating on a long, narrow strip of plastic film. It was developed in Germany
Germany
in 1928, based on magnetic wire recording. Devices that record and play back audio and video using magnetic tape are tape recorders and video tape recorders. A device that stores computer data on magnetic tape is known as a tape drive. Magnetic tape
Magnetic tape
revolutionized broadcast and recording. It allowed radio, which had always been broadcast live, to be recorded for later or repeated airing. It allowed gramophone records to be recorded in multiple parts, which were then mixed and edited with tolerable loss in quality
[...More...]

.