What is the short definition of a computer?

What is the short definition of a computer? : A computer is a device that accepts information (in the form of digitalized data) and manipulates it for some result based on a program , software, or sequence of instructions on how the data is to be processed
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A computer is a digital electronic machine that can be programmed to carry outsequences of arithmetic or logical operations (computation) automatically . Modern computers can perform generic sets ofoperations known as programs. These programs enable computers to perform a wide range of tasks. A computer system is a “complete” computer that includes the hardware, operating system(main software), and peripheral equipment needed and used for “full” operation. This term may also refer to a group of computers that are linked and function together, such as a computer network orcomputer cluster.

Computer control systems are used in a wide range of commercial and industrial goods. Simple special-purpose gadgets like microwaves and remote controls are also included, as are industrial robots and computer-aided design tools used in factories, as well as general-purpose gadgets like desktop computers and portable gadgets like smartphones. The Internet, which connects billions of other computers and users, is powered by computers.

Early computers were meant to be used only for calculations Simple manual instruments like theabacus have aided people in doing calculations since ancient times Early in the Industrial Revolution, some mechanical devices were built to automate long tedious tasks, such as guiding patterns for looms More sophisticatedelectrical machines did specialized analog calculations in the early 20th century The first digital electronic calculating machines were developed duringWorld War II The first semiconductor transistors in the late 1940s were followed by the silicon-basedMOSFET (MOS transistor) and monolithic integrated circuit (IC) chip technologies in the late 1950s, leading to the microprocessor and themicrocomputer revolution in the 1970s The speed, power and versatility of computers have been increasing dramatically ever since then, with transistor counts increasing at a rapid pace (as predicted byMoore’s law), leading to the Digital Revolution during the late 20th to early 21st centuries

Conventionally, a modern computer consists of at least one processing element, typically acentral processing unit (CPU) in the form of a microprocessor, along with some type of computer memory, typicallysemiconductor memory chips. The processing element carries out arithmetic and logical operations, and a sequencing and control unit can change the order of operations in response to stored information. Peripheral devicesinclude input devices (keyboards, mice, joystick, etc.), output devices (monitor screens, printers, etc.), and input/output devices that perform both functions (e.g., the 2000s-era touchscreen). Peripheral devicesallow information to be retrieved from an external source and they enable the result of operations to be saved and retrieved.

Table of Contents

Etymology

Accordingto the Oxford English Dictionary, the first known use of computer was in a 1613 book called The Yong Mans Gleanings by the English writer Richard Brathwait: “I haue [sic]read the truest computer of Times, and the best Arithmetician that euer [sic] breathed, and he reduceth thy dayes into a short number.” This usage of the term referred to a human computer, a person who carried out calculations or computations. The word continued with the same meaning until the middle of the 20th century. During the latter part of this period women were often hired as computersbecause they could be paid less than their male counterparts.[1] By 1943, most human computers were women.[2]

TheOnline Etymology Dictionary gives the first attested use of computer in the 1640s, meaning ‘one who calculates’; this is an “agent noun from compute (v.)”. The Online Etymology Dictionary states that the use of the term to mean ‘calculating machine’ (of any type) is from 1897.” The Online Etymology Dictionary indicates that the”modern use” of the term, to mean ‘programmable digital electronic computer’ dates from “1945 under this name; [in a] theoretical [sense] from 1937, as Turing machine”.[3]

History

Pre-20th century

Devices have been used to aid computation for thousands of years, mostly using one-to-one correspondence with fingers The earliest counting device was probably a form oftally stick Later record keeping aids throughout the Fertile Crescent included calculi (clay spheres, cones, etc ) which represented counts of items, probably livestock or grains, sealed in hollow unbaked claycontainers [a][4] The use of counting rods is one example

The Chinese suanpan () The number represented on this abacus is6,302,715,408

The abacus was initially used for arithmetic tasks The Roman abacus was developed from devices used in Babylonia as early as 2400 BC Since then, many other forms of reckoning boards or tables have beeninvented In a medieval European counting house, a checkered cloth would be placed on a table, and markers moved around on it according to certain rules, as an aid to calculating sums of money [5]

The Antikythera mechanism is believed to be the earliest known mechanical analog computer, according to DerekJ. de Solla Price.[6] It was designed to calculate astronomical positions. It was discovered in 1901 in the Antikythera wreck off the Greek island of Antikythera, betweenKythera and Crete, and has been dated to approximately c. 100 BC. Devices of comparable complexity to the Antikythera mechanism would not reappear until the fourteenth century.[7]

Manymechanical aids to calculation and measurement were constructed for astronomical and navigation use. The planisphere was a star chart invented by Abū Rayhān al-Bīrūnī in the early 11thcentury.[8] The astrolabe was invented in the Hellenistic world in either the 1st or 2nd centuries BC and is often attributed toHipparchus. A combination of the planisphere and dioptra, the astrolabe was effectively an analog computer capable of working out several different kinds of problems in spherical astronomy. An astrolabe incorporating amechanical calendar computer[9][10] and gear-wheels was invented by Abi Bakr ofIsfahan, Persia in 1235.[11] Abū Rayhān al-Bīrūnī invented the first mechanical geared lunisolar calendarastrolabe,[12] an early fixed-wired knowledge processing machine[13] with agear train and gear-wheels,[14] c. 1000 AD.

The sector, a tool for proportion, trigonometry, multiplication, and division calculations as well as other functions like squares and cube roots, was created in the late 16th century and used in gunnery, surveying, and navigation.

The planimeter was a manual instrument to calculate the area of a closed figure by tracing over it with a mechanical linkage

Theslide rule was invented around 16201630 by the English clergyman William Oughtred, shortly after the publication of the concept of the logarithm It is a hand-operated analog computer for doing multiplication anddivision As slide rule development progressed, added scales provided reciprocals, squares and square roots, cubes and cube roots, as well as transcendental functions such as logarithms and exponentials, circular and hyperbolictrigonometry and other functions Slide rules with special scales are still used for quick performance of routine calculations, such as the E6B circular slide rule used for time and distance calculations on lightaircraft

In the 1770s, Pierre Jaquet-Droz, a Swiss watchmaker, built a mechanical doll (automaton) that could write holding a quill pen. By switching the number and order of its internal wheels differentletters, and hence different messages, could be produced. In effect, it could be mechanically “programmed” to read instructions. Along with two other complex machines, the doll is at the Musée d’Art et d’Histoire of Neuchâtel, Switzerland, and stilloperates.[15]

In 18311835, mathematician and engineer Giovanni Plana devised a Perpetual Calendar machine, which, through a system ofpulleys and cylinders and over, could predict the perpetual calendar for every year from AD 0 (that is, 1 BC) to AD 4000, keeping track of leap years and varying day length The tide-predicting machine invented by the Scottish scientistSir William Thomson in 1872 was of great utility to navigation in shallow waters It used a system of pulleys and wires to automatically calculate predicted tide levels for a set period at a particular location

The differential analyser, amechanical analog computer designed to solve differential equations by integration, used wheel-and-disc mechanisms to perform the integration. In 1876, Sir William Thomson had already discussed the possible construction of such calculators, but he had been stymied by the limited output torque of theball-and-disk integrators.[16] In a differential analyzer, the output of one integrator drove the input of the next integrator, or a graphing output. Thetorque amplifier was the advance that allowed these machines to work. Starting in the 1920s, Vannevar Bush and others developed mechanical differential analyzers.

First computer

Charles Babbage, an English mechanical engineer and polymath, originated the concept of a programmable computer. Considered the “father of thecomputer”,[17] he conceptualized and invented the first mechanical computer in the early 19th century. After working on his revolutionary difference engine, designed to aidin navigational calculations, in 1833 he realized that a much more general design, an Analytical Engine, was possible. The input of programs and data was to be provided to the machine via punched cards, a method being used at the time to direct mechanicallooms such as the Jacquard loom. For output, the machine would have a printer, a curve plotter and a bell. The machine would also be able to punch numbers onto cards to be read in later. The Engine incorporated anarithmetic logic unit, control flow in the form of conditional branching andloops, and integrated memory, making it the first design for a general-purpose computer that could be described in modern terms asTuring-complete.[18][19]

The machine was about a century ahead of its time. All the parts for his machine had to be made by hand – this was amajor problem for a device with thousands of parts. Eventually, the project was dissolved with the decision of the British Government to cease funding. Babbage’s failure to complete the analytical engine can be chiefly attributed to political and financial difficulties as well as his desire to develop an increasingly sophisticated computer and to move ahead faster than anyone else couldfollow. Nevertheless, his son, Henry Babbage, completed a simplified version of the analytical engine’s computing unit (the mill) in 1888. He gave a successful demonstration of its use in computing tables in 1906.

Analog computers

During the first half of the 20th century, many scientific computing needs were met by increasingly sophisticated analog computers, which used a direct mechanical or electrical model of the problem as a basis forcomputation However, these were not programmable and generally lacked the versatility and accuracy of modern digital computers [20] The first modern analog computer was atide-predicting machine, invented by Sir William Thomson (later to become Lord Kelvin) in 1872 The differential analyser, a mechanicalanalog computer designed to solve differential equations by integration using wheel-and-disc mechanisms, was conceptualized in 1876 by James Thomson, the elder brother of the more famous Sir William Thomson [16]

Theart of mechanical analog computing reached its zenith with the differential analyzer, built by H. L. Hazen and Vannevar Bush at MIT starting in1927. This built on the mechanical integrators of James Thomson and the torque amplifiers invented by H. W. Nieman. A dozen of these devices were built before their obsolescence became obvious. By the 1950s, the success of digital electronic computers hadspelled the end for most analog computing machines, but analog computers remained in use during the 1950s in some specialized applications such as education (slide rule) and aircraft (control systems).

Digital computers

Electromechanical

By 1938, the United States Navy had developed an electromechanical analog computer small enough to use aboard a submarine This was the TorpedoData Computer, which used trigonometry to solve the problem of firing a torpedo at a moving target During World War II similar devices were developed in other countries as well

Replica of Konrad Zuse’sZ3, the first fully automatic, digital (electromechanical) computer

Early digital computers were electromechanical; electric switches drove mechanical relays to perform the calculation These devices had a low operating speed and were eventually superseded by much fasterall-electric computers, originally using vacuum tubes The Z2, created by German engineer Konrad Zuse in 1939, was one of the earliest examples of an electromechanical relaycomputer [21]

Zuse followed up his first device in 1941 with the Z3, the first operational electromechanical programmable, fully automatic digital computer. [22][23] The Z3’s 2000 relays implemented a 22 bitword length and ran at a clock frequency of roughly 510 Hz. [24] Program code was provided on punched film, and data could be entered manually or stored in 64 words of memory. In some ways, it was quite akin to contemporary machines, having invented a number of innovations like floating-point numbers. Given the technologies available at the time, using a binary system made Zuse’s machines simpler to construct and possibly more reliable than the more difficult-to-implement decimal system (used in Charles Babbage’s earlier design). [25] The Z3 could be upgraded to be Turing complete even though it was not a fully functional universal computer. [26][27].

Zuse’s next computer, theZ4, became the world’s first commercial computer; after initial delay due to the Second World War, it was completed in 1950 and delivered to the ETH Zurich.[28] The computer wasmanufactured by Zuse’s own company, Zuse KG [de], which was founded in 1941 as the first company with the sole purpose of developing computers.[28]

Vacuum tubes and digital electronic circuits

Purely electronic circuit elements soon replaced their mechanical and electromechanical equivalents, at the same time that digital calculation replaced analog. The engineerTommy Flowers, working at the Post Office Research Station in London in the 1930s, began to explore the possible use of electronics for thetelephone exchange. Experimental equipment that he built in 1934 went into operation five years later, converting a portion of the telephone exchange network into an electronic data processing system, using thousands of vacuum tubes.[20] In the US, John Vincent Atanasoff and Clifford E. Berry ofIowa State University developed and tested the Atanasoff–Berry Computer (ABC) in 1942,[29] the first “automatic electronic digitalcomputer”.[30] This design was also all-electronic and used about 300 vacuum tubes, with capacitors fixed in a mechanically rotating drum for memory.[31]

During World War II, the British code-breakers atBletchley Park achieved a number of successes at breaking encrypted German military communications The German encryption machine, Enigma, was first attacked with the help of the electro-mechanical bombes which were oftenrun by women [32][33] To crack the more sophisticated German Lorenz SZ 40/42 machine, used for high-level Army communications,Max Newman and his colleagues commissioned Flowers to build the Colossus [31] He spent eleven months from early February 1943 designing and building the firstColossus [34] After a functional test in December 1943, Colossus was shipped to Bletchley Park, where it was delivered on 18 January 1944[35] and attacked its first message on 5February [31]

The first electronic digital programmable computer in history was named Colossus. [20] It made use of a lot of vacuum tubes for the valves. Although it could be set up to carry out a number of booleanlogical operations on the data it received, it had paper-tape input and was not Turing-complete. There were made nine Mk II Colossi (after the Mk I was converted to a Mk II, there were ten machines total). Colossus Mark I had 1,500 thermionic valves (tubes), but Mark II had 2,400, which was five times faster and easier to use than Mark I, speeding up the decoding process considerably. [36][37].

The United States Army used ENIAC, the first electronic Turing-complete machine, to calculate ballistic trajectory.

TheENIAC[38] (Electronic Numerical Integrator and Computer) was the first electronic programmable computer built in the U.S. Although the ENIAC was similar to the Colossus, it was much faster, more flexible, and it wasTuring-complete. Like the Colossus, a “program” on the ENIAC was defined by the states of its patch cables and switches, a far cry from the stored program electronic machines that came later. Once a program was written, it had to be mechanically set into the machine with manual resetting of plugs andswitches. The programmers of the ENIAC were six women, often known collectively as the “ENIAC girls”.[39][40]

It combined the high speed of electronics with the ability to be programmedfor many complex problems. It could add or subtract 5000 times a second, a thousand times faster than any other machine. It also had modules to multiply, divide, and square root. High speed memory was limited to 20 words (about 80 bytes). Built under the direction of John Mauchly and J. Presper Eckertat the University of Pennsylvania, ENIAC’s development and construction lasted from 1943 to full operation at the end of 1945. The machine was huge, weighing 30 tons, using 200 kilowatts of electric power and contained over 18,000 vacuum tubes, 1,500 relays, and hundreds of thousands of resistors, capacitors, and inductors.[41]

Moderncomputers

Concept of modern computer

The principle of the modern computer was proposed by Alan Turing in his seminal 1936 paper,[42] On Computable Numbers. Turing proposed a simple device that he called “Universal Computingmachine” and that is now known as a universal Turing machine. He proved that such a machine is capable of computing anything that is computable by executing instructions (program) stored on tape, allowing the machine to be programmable. The fundamental concept of Turing’s design is thestored program, where all the instructions for computing are stored in memory. Von Neumann acknowledged that the central concept of the modern computer was due to this paper.[43] Turingmachines are to this day a central object of study in theory of computation. Except for the limitations imposed by their finite memory stores, modern computers are said to be Turing-complete, which is to say, they havealgorithm execution capability equivalent to a universal Turing machine.

Stored programs

Early computing machines had fixed programs. Changing its function required the re-wiring andre-structuring of the machine.[31] With the proposal of the stored-program computer this changed. A stored-program computer includes by design an instruction set and can store in memory a set of instructions (aprogram) that details the computation. The theoretical basis for the stored-program computer was laid out by Alan Turing in his 1936 paper. In 1945, Turing joined theNational Physical Laboratory and began work on developing an electronic stored-program digital computer. His 1945 report “Proposed Electronic Calculator” was the first specification for such a device. John von Neumann at theUniversity of Pennsylvania also circulated his First Draft of a Report on the EDVAC in 1945.[20]

TheManchester Baby was the world’s first stored-program computer. It was built at the University of Manchester in England byFrederic C. Williams, Tom Kilburn and Geoff Tootill, and ran its first program on 21 June1948.[44] It was designed as a testbed for the Williams tube, the first random-access digitalstorage device.[45] Although the computer was described as “small and primitive” by a 1998 retrospective, it was the first working machine to contain all of the elements essential to a modern electronic computer.[46] As soon as the Baby had demonstrated the feasibility of itsdesign, a project began at the university to develop it into a practically useful computer, the Manchester Mark 1.

The Mark 1 in turn quickly became the prototype for the Ferranti Mark 1, the world’s first commercially available general-purposecomputer [47] Built by Ferranti, it was delivered to the University of Manchester in February 1951 At least seven of these later machines were delivered between 1953 and 1957, one of them toShell labs in Amsterdam [48] In October 1947 the directors of British catering company J Lyonsand Company decided to take an active role in promoting the commercial development of computers Lyons’s LEO I computer, modelled closely on the CambridgeEDSAC of 1949, became operational in April 1951[49] and ran the world’s first routine office computer job

Grace Hopper was the first to develop a compiler for a programming language.[2]

Transistors

The concept of a field-effect transistor was proposed by Julius Edgar Lilienfeld in 1925. John Bardeen andWalter Brattain, while working under William Shockley at Bell Labs, built the first working transistor, thepoint-contact transistor, in 1947, which was followed by Shockley’s bipolar junction transistor in1948.[50][51] From 1955 onwards, transistors replaced vacuum tubes in computer designs, giving rise to the “second generation” of computers. Compared to vacuumtubes, transistors have many advantages: they are smaller, and require less power than vacuum tubes, so give off less heat. Junction transistors were much more reliable than vacuum tubes and had longer, indefinite, service life. Transistorized computers could contain tens of thousands of binary logic circuits in a relatively compact space. However, early junction transistors wererelatively bulky devices that were difficult to manufacture on a mass-production basis, which limited them to a number of specialised applications.[52]

A group at the University of Manchester led by Tom Kilburn created and constructed a machine using the recently invented transistors in place of valves. [53] By 1953, they had built the first transistorized computer in the history of the world, and in April 1955, a second version was finished there. It was not the first fully transistorized computer, as the device did use valves to generate its 125 kHz clock waveforms and in the circuitry to read and write on its magnetic drum memory. This honor belongs to the Harwell CADET of 1955,[54] created by the electronics department of the Atomic Energy Research Establishment atHarwell. [54][55].

Showing the source, drain, body, and gate terminals of a MOSFET (MOS transistor). A pink-colored insulating layer separates the gate from the body.

The metal–oxide–silicon field-effect transistor (MOSFET), also known as the MOS transistor, was invented byMohamed M. Atalla and Dawon Kahng at Bell Labs in 1959.[56] It was the first truly compact transistor that could be miniaturised and mass-produced for a widerange of uses.[52] With its high scalability,[57] and much lower power consumption and higher density than bipolar junctiontransistors,[58] the MOSFET made it possible to build high-density integrated circuits.[59][60] In addition to data processing, it also enabled the practical use of MOS transistors as memory cell storage elements, leading to the development of MOSsemiconductor memory, which replaced earlier magnetic-core memory in computers. The MOSFET led to the microcomputerrevolution,[61] and became the driving force behind the computerrevolution.[62][63] The MOSFET is the most widely used transistor incomputers,[64][65] and is the fundamental building block of digitalelectronics.[66]

Integrated circuits

Die photograph of aMOS 6502, an early 1970s microprocessor integrating 3500 transistors on a single chip

Integrated circuits are typically packaged in plastic, metal, or ceramic cases to protect the IC from damage and for ease of assembly

When integrated circuits (ICs) were invented, computing power made its next significant leap forward. Geoffrey W., a radar scientist for the Royal Radar Establishment of the Ministry of Defence, was the first to come up with the concept of the integrated circuit. A. Dummer. The first public description of an integrated circuit was given by Dummer at the Symposium on Progress in Quality Electronic Components in Washington, D.C. C. on 7 May1952. [67].

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The first working ICs were invented by Jack Kilby at Texas Instruments and RobertNoyce at Fairchild Semiconductor.[68] Kilby recorded his initial ideas concerning the integrated circuit in July 1958, successfully demonstrating the first working integrated example on 12 September1958.[69] In his patent application of 6 February 1959, Kilby described his new device as “a body of semiconductor material … wherein all the components of the electronic circuit are completelyintegrated”.[70][71] However, Kilby’s invention was a hybrid integrated circuit (hybrid IC), rather than amonolithic integrated circuit (IC) chip.[72] Kilby’s IC had external wire connections, which made it difficult tomass-produce.[73]

Half a year after Kilby, Noyce also came up with his own concept for an integrated circuit. The first authentic monolithic ICchip was created by Noyce [74]. His chip offered many solutions to real-world issues that Kilby’s did not. It was made of silicon at Fairchild Semiconductor, whereas Kilby’s chip was made of germanium. The planar method, created by his colleague Jean Hoerni in the beginning of 1959, was used to create Noyce’s monolithic integrated circuit. The planar procedure itself was based on Mohamed M. The late 1950s work of Atalla on silicon dioxide passivation of semiconductor surfaces [76][77][78].

Modern monolithic ICs are predominantly MOS(metal-oxide-semiconductor) integrated circuits, built from MOSFETs (MOS transistors) [79] The earliest experimental MOS IC to be fabricated was a 16-transistor chip built byFred Heiman and Steven Hofstein at RCA in 1962 [80] General Microelectronics later introduced the first commercial MOS IC in1964,[81] developed by Robert Norman [80] Following the development of the self-aligned gate (silicon-gate) MOS transistor byRobert Kerwin, Donald Klein and John Sarace at Bell Labs in 1967, the first silicon-gate MOS IC with self-aligned gates was developed byFederico Faggin at Fairchild Semiconductor in 1968 [82] The MOSFET has since become the most critical device component in modern ICs [83]

The development of the MOSintegrated circuit led to the invention of the microprocessor,[84][85] and heralded an explosion in the commercialand personal use of computers. While the subject of exactly which device was the first microprocessor is contentious, partly due to lack of agreement on the exact definition of the term “microprocessor”, it is largely undisputed that the first single-chip microprocessor was the Intel 4004,[86]designed and realized by Federico Faggin with his silicon-gate MOS IC technology,[84] along with Ted Hoff, Masatoshi Shima andStanley Mazor at Intel.[b][88] In the early 1970s, MOS IC technology enabled theintegration of more than 10,000 transistors on a single chip.[60]

System on a Chip (SoCs) are complete computers on amicrochip (or chip) the size of a coin.[89] They may or may not have integrated RAM andflash memory. If not integrated, the RAM is usually placed directly above (known as Package on package) or below (on the opposite side of the circuit board) the SoC, and the flash memory is usuallyplaced right next to the SoC, this all done to improve data transfer speeds, as the data signals don’t have to travel long distances. Since ENIAC in 1945, computers have advanced enormously, with modern SoCs (Such as the Snapdragon 865) being the size of a coin while also being hundreds of thousands of times more powerful than ENIAC, integrating billions of transistors, and consuming only a few watts of power.

Mobile computers

The firstmobile computers were heavy and ran from mains power The 50lb (23kg) IBM 5100 was an early example Later portables such as the Osborne 1 andCompaq Portable were considerably lighter but still needed to be plugged in The first laptops, such as the Grid Compass, removed this requirement by incorporating batteries and with the continued miniaturization ofcomputing resources and advancements in portable battery life, portable computers grew in popularity in the 2000s [90] The same developments allowed manufacturers to integrate computing resources into cellular mobile phones by the early 2000s

These smartphones andtablets run on a variety of operating systems and recently became the dominant computing device on the market.[91] These are powered by System on a Chip (SoCs), which are completecomputers on a microchip the size of a coin.[89]

Types

Computers can be classified in a number of different ways, including:

By architecture

  • Analog computer
  • Digital computer
  • Hybrid computer
  • Harvard architecture
  • Von Neumann architecture
  • Complex instruction set computer
  • Reduced instruction set computer

By size, form-factor and purpose

  • Supercomputer
  • Mainframe computer
  • Minicomputer (term no longer used)
  • Server
    • Rackmount server
    • Blade server
    • Tower server
  • Personal computer
    • Workstation
    • Microcomputer (term no longer used)
      • Home computer
    • Desktop computer
      • Tower desktop
      • Slimline desktop
        • Multimedia computer (non-linear editing system computers, video editing PCs and the like)
        • Gaming computer
      • All-in-one PC
      • Nettop (Smallform factor PCs, Mini PCs)
      • Home theater PC
      • Keyboard computer
      • Portable computer
      • Thin client
      • Internet appliance
    • Laptop
      • Desktop replacementcomputer
      • Gaming laptop
      • Rugged laptop
      • 2-in-1 PC
      • Ultrabook
      • Chromebook
      • Subnotebook
      • Netbook
  • Mobile computers:
    • Tablet computer
    • Smartphone
    • Ultra-mobile PC
    • Pocket PC
    • Palmtop PC
    • Handheld PC
  • Wearable computer
    • Smartwatch
    • Smartglasses
  • Single-board computer
  • Plug computer
  • Stick PC
  • Programmable logic controller
  • Computer-on-module
  • System on module
  • System in a package
  • System-on-chip (Also known as an Application Processor or AP if it lacks circuitry such as radio circuitry)
  • Microcontroller

Hardware

Video demonstrating the standard components of a”slimline” computer

The term hardware covers all of those parts of a computer that are tangible physical objects. Circuits, computer chips, graphic cards, sound cards, memory (RAM), motherboard, displays, power supplies, cables, keyboards, printers and “mice” input devices are all hardware.

History of computinghardware

First generation(mechanical/electromechanical) Calculators Pascal’s calculator, Arithmometer, Difference engine,Quevedo’s analytical machines
Programmable devices Jacquard loom, Analytical engine, IBM ASCC/Harvard Mark I, Harvard Mark II,IBM SSEC, Z1, Z2, Z3
Second generation(vacuum tubes) Calculators Atanasoff–Berry Computer, IBM 604, UNIVAC 60, UNIVAC 120
Programmable devices Colossus, ENIAC, Manchester Baby, EDSAC,Manchester Mark 1, Ferranti Pegasus, Ferranti Mercury, CSIRAC,EDVAC, UNIVAC I, IBM 701, IBM 702, IBM 650,Z22
Third generation(discrete transistors and SSI, MSI, LSI integrated circuits) Mainframes IBM 7090, IBM 7080, IBM System/360, BUNCH
Minicomputer HP 2116A, IBM System/32, IBM System/36, LINC, PDP-8, PDP-11
Desktop Computer HP 9100
Fourth generation(VLSI integrated circuits) Minicomputer VAX, IBM AS/400
4-bit microcomputer Intel 4004, Intel 4040
8-bit microcomputer Intel 8008, Intel 8080, Motorola 6800, Motorola 6809,MOS Technology 6502, Zilog Z80
16-bit microcomputer Intel 8088, Zilog Z8000, WDC 65816/65802
32-bit microcomputer Intel 80386, Pentium, Motorola 68000, ARM
64-bit microcomputer[c] Alpha, MIPS, PA-RISC, PowerPC, SPARC,x86-64, ARMv8-A
Embedded computer Intel 8048, Intel 8051
Personal computer Desktop computer, Home computer, Laptop computer, Personal digital assistant (PDA),Portable computer, Tablet PC, Wearable computer
Theoretical/experimental Quantum computer IBM Q System One
Chemical computer
DNA computing
Optical computer
Spintronics-based computer
Wetware/Organic computer

Other hardware topics

Peripheral device (input/output) Input Mouse, keyboard, joystick, image scanner,webcam, graphics tablet, microphone
Output Monitor, printer, loudspeaker
Both Floppy disk drive, hard disk drive, optical disc drive, teleprinter
Computer buses Short range RS-232, SCSI, PCI, USB
Long range (computer networking) Ethernet, ATM, FDDI

A general-purpose computer has four main components: the arithmetic logic unit (ALU), the control unit, the memory, and theinput and output devices (collectively termed I/O). These parts are interconnected by buses, often made of groups of wires. Inside each of these parts are thousands to trillions of smallelectrical circuits which can be turned off or on by means of an electronic switch. Each circuit represents a bit (binary digit) of information so that when the circuit is on it represents a “1”, and when off it represents a “0”(in positive logic representation). The circuits are arranged in logic gates so that one or more of the circuits may control the state of one or more of the other circuits.

Input devices

When unprocessed data is sent to the computer with the help of input devices, the data is processed and sent to output devices. The input devices may be hand-operated orautomated. The act of processing is mainly regulated by the CPU. Some examples of input devices are:

  • Computer keyboard
  • Digital camera
  • Digital video
  • Graphics tablet
  • Image scanner
  • Joystick
  • Microphone
  • Mouse
  • Overlay keyboard
  • Real-time clock
  • Trackball
  • Touchscreen
  • Light pen

Output devices

The means through which computer gives output are known as output devices. Some examples of output devices are:

  • Computer monitor
  • Printer
  • PC speaker
  • Projector
  • Sound card
  • Video card

Control unit

Graph illustrating the decoding process used by the control system to understand a specific MIPS architecture instruction.

The control unit (often called a control system or central controller) manages the computer’s various components; it reads and interprets (decodes) the program instructions, transforming them into control signals that activate other parts of the computer [d] Control systems inadvanced computers may change the order of execution of some instructions to improve performance

A key component common to all CPUs is the program counter, a special memory cell (a register) that keeps track of which location in memory the next instruction is to be readfrom [e]

The control system’s function is as follows— this is a simplified description, and some of these steps may be performed concurrently or in a different order depending on the type of CPU:

  • Read the code for the next instruction from the cell indicated by the program counter.
  • Decode the numerical code for the instruction into a set of commands or signalsfor each of the other systems.
  • Increment the program counter so it points to the next instruction.
  • Read whatever data the instruction requires from cells in memory (or perhaps from an input device). The location of this required data is typically stored within the instruction code.
  • Provide the necessary data to an ALU or register.
  • If the instruction requires an ALU or specialized hardware to complete, instruct the hardware to perform the requested operation.
  • Write the result from the ALU back to a memory location or to a register or perhaps an output device.
  • Jump back to step (1).
  • Since the program counter is (conceptually) just another set of memory cells, it can be changed by calculations done in the ALU. Adding 100 to the program counter would cause the next instruction to be read from a place 100 locations further down the program. Instructions that modify the program counter are often known as “jumps” and allow for loops(instructions that are repeated by the computer) and often conditional instruction execution (both examples of control flow).

    The sequence of operations that the control unit goes through to process an instruction is in itself like a short computer program, and indeed, in some more complex CPUdesigns, there is another yet smaller computer called a microsequencer, which runs a microcode program that causes all of these events to happen.

    Central processing unit (CPU)

    The control unit, ALU,and registers are collectively known as a central processing unit (CPU). Early CPUs were composed of many separate components. Since the 1970s, CPUs have typically been constructed on a single MOS integrated circuit chip called amicroprocessor.

    Arithmetic logic unit (ALU)

    The ALU is capable of performing two classes of operations: arithmetic and logic.[92] The set of arithmetic operations that aparticular ALU supports may be limited to addition and subtraction, or might include multiplication, division, trigonometry functions such as sine, cosine, etc., and square roots. Some can operate only on whole numbers (integers)while others use floating point to represent real numbers, albeit with limited precision. However, any computer that is capable of performing just the simplest operations can be programmed to break down the more complex operations into simple steps that it can perform. Therefore, any computer can beprogrammed to perform any arithmetic operation—although it will take more time to do so if its ALU does not directly support the operation. An ALU may also compare numbers and return Boolean truth values (true or false) depending on whether one is equal to, greater than or less than the other (“is 64 greater than 65?”). Logic operations involveBoolean logic: AND, OR, XOR, andNOT. These can be useful for creating complicated conditional statements and processing Boolean logic.

    Superscalar computers may contain multiple ALUs, allowing them to process several instructions simultaneously.[93] Graphics processors and computers withSIMD and MIMD features often contain ALUs that can perform arithmetic on vectors andmatrices.

    Memory

    A computer’s memory can be viewed as a list of cells into which numbers can be placed or read. Each cell has a numbered “address” and can store a single number. The computer can be instructed to “put the number 123 into the cell numbered 1357” or to “add the number that is in cell 1357 to the number that is in cell 2468 andput the answer into cell 1595.” The information stored in memory may represent practically anything. Letters, numbers, even computer instructions can be placed into memory with equal ease. Since the CPU does not differentiate between different types of information, it is the software’s responsibility to give significance to what the memory sees as nothing but a series of numbers.

    Each memory cell in almost all current computers is configured to store binary numbers as groups of eight bits (referred to as bytes). 256 different numbers, ranging from 0 to 255 or 128 to 127, can be represented by each byte (28 = 256). Several consecutive bytes (typically two, four, or eight) may be used to store larger numbers. When storing negative numbers, two’s complement notation is typically used. Aside from specialized applications or historical contexts, other arrangements are possible but are typically not observed. As long as the information can be represented numerically, a computer can store it in memory. The amount of memory in modern computers is in the trillions or even billions of bytes.

    The CPU contains a special set of memory cells calledregisters that can be read and written to much more rapidly than the main memory area There are typically between two and one hundred registers depending on the type of CPU Registers are used for the most frequently needed data items to avoid having to access main memory every time data is needed As data is constantly being worked on, reducing the need to access main memory (which isoften slow compared to the ALU and control units) greatly increases the computer’s speed

    Computer main memory comes in two principal varieties:

    • random-access memory or RAM
    • read-only memory or ROM

    ROM is preloaded with data and software that never changes, so the CPU can only read from it. RAM can be read and written to whenever the CPU instructs it to. Normally, the initial start-up instructions for a computer are stored in ROM. Typically, when a computer’s power is turned off, the contents of RAM are deleted, whereas the data in ROM is retained indefinitely. Every time a PC is powered on or reset, a specialized program called the BIOS is stored in the ROM. This program manages the computer’s operating system being loaded from the hard drive into RAM. The entirety of the necessary software may be kept in ROM in embedded computers, which frequently lack disk drives. Due to its conceptual similarity to hardware rather than software, software that is stored in ROM is frequently referred to as firmware. Due to its ability to both be rewritable and retain data even when turned off, flash memory blurs the lines between ROM and RAM. However, due to the fact that it is typically much slower than traditional ROM and RAM, its use is only permitted in circumstances where high speed is essential. [f].

    In more sophisticated computers there may be one or more RAM cache memories, which are slower than registers but faster than main memory. Generally computers with this sort of cache are designed to move frequently needed data into the cache automatically, often without the needfor any intervention on the programmer’s part.

    Input/output (I/O)

    I/O is the means bywhich a computer exchanges information with the outside world.[95] Devices that provide input or output to the computer are called peripherals.[96] On a typical personal computer,peripherals include input devices like the keyboard and mouse, and output devices such as the display and printer.Hard disk drives, floppy disk drives and optical disc drives serve as both input and output devices.Computer networking is another form of I/O. I/O devices are often complex computers in their own right, with their own CPU and memory. A graphics processing unit might contain fifty or more tiny computers that perform the calculations necessary to display3D graphics.[citation needed] Modern desktop computers containmany smaller computers that assist the main CPU in performing I/O. A 2016-era flat screen display contains its own computer circuitry.

    Multitasking

    While a computer may be viewed as running one gigantic program stored in its main memory, in some systems it is necessary to give the appearance of running several programs simultaneously. This is achieved by multitasking i.e. having the computer switch rapidly between running each program inturn.[97] One means by which this is done is with a special signal called an interrupt, which can periodically cause the computer to stop executing instructions where it was and do something else instead. By remembering where it was executing prior to the interrupt, the computer can return to thattask later. If several programs are running “at the same time”. then the interrupt generator might be causing several hundred interrupts per second, causing a program switch each time. Since modern computers typically execute instructions several orders of magnitude faster than human perception, it may appear that many programs are running at the same time even though only one is ever executing in any given instant. This method of multitasking is sometimes termed “time-sharing” since eachprogram is allocated a “slice” of time in turn.[98]

    Before the era of inexpensive computers, the principal use for multitasking was to allow many people to share the same computer. Seemingly, multitasking would cause a computer that is switching between several programs to run more slowly, in direct proportion to the number of programs it is running, but most programs spend muchof their time waiting for slow input/output devices to complete their tasks. If a program is waiting for the user to click on the mouse or press a key on the keyboard, then it will not take a “time slice” until the event it is waiting for has occurred. This frees up time for other programs to execute so that many programs may be run simultaneously without unacceptable speed loss.

    Multiprocessing

    Cray designed many supercomputers that used multiprocessing heavily.

    Some computers are designed to distribute their work across several CPUs in a multiprocessing configuration, a technique onceemployed in only large and powerful machines such as supercomputers, mainframe computers and servers Multiprocessor andmulti-core (multiple CPUs on a single integrated circuit) personal and laptop computers are now widely available, and are being increasingly used in lower-end markets as a result

    Supercomputers in particular often have highly unique architectures that differ significantly from the basic stored-program architecture and from general-purposecomputers.[g] They often feature thousands of CPUs, customized high-speed interconnects, and specialized computing hardware. Such designs tend to be useful for only specialized tasks due to the large scale of program organization required to successfully utilize most of the available resources at once. Supercomputers usually see usage in large-scalesimulation, graphics rendering, and cryptography applications, as well as with other so-called”embarrassingly parallel” tasks.

    Software

    Software refers to parts of the computer which do not have a material form, such as programs, data, protocols, etc. Software is that part of a computer system that consists of encoded information or computer instructions, in contrast to the physicalhardware from which the system is built. Computer software includes computer programs, libraries and related non-executabledata, such as online documentation or digital media. It is often divided into systemsoftware and application software Computer hardware and software require each other and neither can be realistically used on its own. When software is stored in hardware that cannot easily be modified, such as with BIOSROM in an IBM PC compatible computer, it is sometimes called “firmware”.

    Operating system /System Software Unix and BSD UNIX System V, IBM AIX, HP-UX, Solaris(SunOS), IRIX, List of BSD operating systems
    Linux List of Linux distributions, Comparison of Linux distributions
    Microsoft Windows Windows 95, Windows 98, Windows NT, Windows 2000,Windows ME, Windows XP, Windows Vista, Windows 7,Windows 8, Windows 8.1, Windows 10, Windows 11
    DOS 86-DOS (QDOS), IBM PC DOS, MS-DOS, DR-DOS, FreeDOS
    Macintosh operating systems Classic Mac OS, macOS (previously OS X and Mac OS X)
    Embedded and real-time List of embedded operating systems
    Experimental Amoeba, Oberon–AOS, Bluebottle, A2, Plan 9 from Bell Labs
    Library Multimedia DirectX, OpenGL, OpenAL, Vulkan (API)
    Programming library C standard library, Standard Template Library
    Data Protocol TCP/IP, Kermit, FTP, HTTP,SMTP
    File format HTML, XML, JPEG, MPEG,PNG
    User interface Graphical user interface (WIMP) Microsoft Windows, GNOME, KDE, QNX Photon,CDE, GEM, Aqua
    Text-based user interface Command-line interface, Text user interface
    Application Software Office suite Word processing, Desktop publishing, Presentation program,Database management system, Scheduling & Time management, Spreadsheet, Accounting software
    Internet Access Browser, Email client, Web server, Mail transfer agent,Instant messaging
    Design and manufacturing Computer-aided design, Computer-aided manufacturing, Plant management, Robotic manufacturing, Supply chain management
    Graphics Raster graphics editor, Vector graphics editor, 3D modeler, Animation editor, 3D computer graphics, Video editing, Image processing
    Audio Digital audio editor, Audio playback, Mixing, Audiosynthesis, Computer music
    Software engineering Compiler, Assembler, Interpreter, Debugger,Text editor, Integrated development environment, Software performance analysis,Revision control, Software configuration management
    Educational Edutainment, Educational game, Serious game, Flight simulator
    Games Strategy, Arcade, Puzzle, Simulation,First-person shooter, Platform, Massively multiplayer,Interactive fiction
    Misc Artificial intelligence, Antivirus software, Malware scanner,Installer/Package management systems, File manager

    Languages

    There are thousands of different programming languages—some intended for general purpose, others useful for only highly specialized applications.

    Programming languages

    Lists of programming languages Timeline of programming languages, List of programming languages by category, Generational list of programming languages, List of programming languages, Non-English-based programming languages
    Commonly used assembly languages ARM, MIPS, x86
    Commonly used high-level programming languages Ada, BASIC, C, C++,C#, COBOL, Fortran, PL/I, REXX,Java, Lisp, Pascal, ObjectPascal
    Commonly used scripting languages Bourne script, JavaScript, Python, Ruby,PHP, Perl

    Programs

    The defining feature of modern computers which distinguishes them from all other machines is that they can be programmed. That is to say that some type of instructions (theprogram) can be given to the computer, and it will process them. Modern computers based on the von Neumann architecture often have machine code in the form of an imperative programming language. In practical terms, a computer program may be just a few instructions or extend to many millions of instructions, as do the programs for word processors and web browsers for example. A typical modern computer can execute billions of instructions per second(gigaflops) and rarely makes a mistake over many years of operation. Large computer programs consisting of several million instructions may take teams of programmers years to write, and due to the complexity of the task almost certainly contain errors.

    Stored programarchitecture

    This section applies to most common RAM machinebased computers

    In most cases, computer instructions are simple: add one number to another, move some data from one location to another, send a message to some external device, etc. These instructions are read from the computer’smemory and are generally carried out (executed) in the order they were given. However, there are usually specialized instructions to tell the computer to jump ahead or backwards to some other place in the program and to carry on executing from there. These are called “jump”instructions (or branches). Furthermore, jump instructions may be made to happen conditionally so that different sequences of instructions may be used depending on the result of some previous calculation or some external event. Many computers directly supportsubroutines by providing a type of jump that “remembers” the location it jumped from and another instruction to return to the instruction following that jump instruction.

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    Program execution might be likened to reading a book While a person will normally read each word and line in sequence, they may at times jump back to an earlier place in the text or skip sections that are not of interest Similarly, a computer may sometimes go back and repeat the instructions in some section of the program over and over again until some internal condition is met This is called the flow of control within the program and it is what allows the computer to perform tasks repeatedly without human intervention

    Comparatively, a person using a pocketcalculator can perform a basic arithmetic operation such as adding two numbers with just a few button presses. But to add together all of the numbers from 1 to 1,000 would take thousands of button presses and a lot of time, with a near certainty of making a mistake. On the other hand, a computer may be programmed to do this with just a few simple instructions. The following example is written in theMIPS assembly language:

      begin:  addi $8, $0,            # initialize sum to 0  addi $9, $0, 1           # set first number to add = 1  loop:  slti $10, $9, 1000       # check if the number is less than 1000  beq $10, $0, finish      # if odd number is greater than n then exit  add $8, $8, $9           # update sum  addi $9, $9, 1           # get next number  j loop                   # repeat the summing process  finish:  add $2, $8, $0           # put sum in output register

    Once told to run this program, the computer will perform the repetitive addition task without further human intervention. It will almost never make a mistake and a modern PC can complete the task in a fraction of a second.

    Machine code

    In most computers, individual instructions are storedas machine code with each instruction being given a unique number (its operation code or opcode for short) The command to add two numbers together would have one opcode; the command to multiply them would have a different opcode, and so on The simplest computers are able to perform any of a handful of differentinstructions; the more complex computers have several hundred to choose from, each with a unique numerical code Since the computer’s memory is able to store numbers, it can also store the instruction codes This leads to the important fact that entire programs (which are just lists of these instructions) can be represented as lists of numbers and can themselves be manipulated inside the computer in the same way as numeric data The fundamental concept of storing programs in the computer’smemory alongside the data they operate on is the crux of the von Neumann, or stored program, architecture [100][101] In some cases, a computer might store some or all of its program in memory that is kept separate from the data it operates on This is called theHarvard architecture after the Harvard Mark I computer Modern von Neumann computers display some traits of the Harvard architecture in their designs, such as in CPU caches

    While it is possible towrite computer programs as long lists of numbers (machine language) and while this technique was used with many early computers,[h] it is extremely tedious and potentially error-prone to do so in practice, especially for complicated programs Instead, each basic instruction can be given ashort name that is indicative of its function and easy to remember a mnemonic such as ADD, SUB, MULT or JUMP These mnemonics are collectively known as a computer’s assembly language Converting programs written in assembly language into something the computer can actually understand (machine language)is usually done by a computer program called an assembler

    A 1970s punched card containing one line from a Fortran program. The card reads: “Z(1) = Y + W(1)” and is labeled “PROJ039” for identification purposes.

    Programming language

    Programminglanguages provide various ways of specifying programs for computers to run. Unlike natural languages, programming languages are designed to permit no ambiguity and to be concise. They are purely written languages and are often difficult to read aloud. They are generally either translated into machinecode by a compiler or an assembler before being run, or translated directly at run time by an interpreter. Sometimes programs are executed by a hybrid method of the two techniques.

    Low-level languages

    Machine languages and the assembly languages that represent them (collectively termed low-level programming languages) are generally unique to the particular architecture of a computer’s central processing unit (CPU). For instance, an ARMarchitecture CPU (such as may be found in a smartphone or a hand-held videogame) cannot understand the machine language of an x86 CPU that might be in aPC.[i] Historically a significant number of other cpu architectures were created and saw extensive use, notably including the MOS Technology 6502 and 6510 in addition to the Zilog Z80.

    High-level languages

    Although considerablyeasier than in machine language, writing long programs in assembly language is often difficult and is also error prone. Therefore, most practical programs are written in more abstract high-level programming languages that are able to express the needs of the programmer moreconveniently (and thereby help reduce programmer error). High level languages are usually “compiled” into machine language (or sometimes into assembly language and then into machine language) using another computer program called a compiler.[j] High level languages are less related to the workings ofthe target computer than assembly language, and more related to the language and structure of the problem(s) to be solved by the final program. It is therefore often possible to use different compilers to translate the same high level language program into the machine language of many different types of computer. This is part of the means by which software like video games may be made available for different computer architectures such as personal computers and variousvideo game consoles.

    Program design

    Program design of small programs is relatively simple and involves the analysis of the problem, collection of inputs, using the programming constructs within languages, devising or using established procedures and algorithms, providing data for output devices and solutions to the problem as applicable. Asproblems become larger and more complex, features such as subprograms, modules, formal documentation, and new paradigms such as object-oriented programming are encountered. Large programs involving thousands of line of code and more require formal software methodologies. The task of developing large software systems presents a significant intellectual challenge. Producing software with anacceptably high reliability within a predictable schedule and budget has historically been difficult; the academic and professional discipline of software engineering concentrates specifically on this challenge.

    Bugs

    The Harvard Mark II computer’s relay was home to the very first computer bug, a moth that was discovered trapped there.

    Errors in computer programs are called “bugs”. They may be benign and not affect the usefulness of the program, or have only subtle effects. But in some cases, they may cause the program or the entire system to”hang”, becoming unresponsive to input such as mouse clicks or keystrokes, to completely fail, or tocrash.[102] Otherwise benign bugs may sometimes be harnessed for malicious intent by an unscrupulous user writing an exploit, code designed to take advantage ofa bug and disrupt a computer’s proper execution. Bugs are usually not the fault of the computer. Since computers merely execute the instructions they are given, bugs are nearly always the result of programmer error or an oversight made in the program’s design.[k] Admiral Grace Hopper, anAmerican computer scientist and developer of the first compiler, is credited for having first used the term “bugs” in computing after a dead moth was found shorting a relay in the Harvard Mark II computer in September1947.[103]

    Networking and the Internet

    A portion of the Internet’s routes are visualized.

    Computers have been used to coordinate information between multiple locations since the 1950s The U S military’sSAGE system was the first large-scale example of such a system, which led to a number of special-purpose commercial systems such asSabre [104] In the 1970s, computer engineers at research institutions throughout the United States began to link their computers together using telecommunications technology The effort was funded by ARPA (now DARPA), and the computer network that resulted was called the ARPANET [105] The technologies that made the Arpanet possible spread and evolved

    In time, the network spreadbeyond academic and military institutions and became known as the Internet. The emergence of networking involved a redefinition of the nature and boundaries of the computer. Computer operating systems and applications were modified to include the ability to define and access the resources of other computers on the network, such as peripheral devices, stored information, and the like, as extensions of the resources of an individual computer. Initially these facilities were available primarily topeople working in high-tech environments, but in the 1990s the spread of applications like e-mail and the World Wide Web, combined with the development of cheap, fast networking technologies like Ethernet andADSL saw computer networking become almost ubiquitous. In fact, the number of computers that are networked is growing phenomenally. A very large proportion of personal computers regularly connect to the Internet to communicate and receive information. “Wireless” networking, often utilizing mobile phone networks, has meant networking is becoming increasinglyubiquitous even in mobile computing environments.

    Unconventional computers

    A computer does not need to be electronic, nor even have a processor, norRAM, nor even a hard disk. While popular usage of the word “computer” is synonymous with a personal electronic computer,[l] the modern definition of a computer is literally: “A devicethat computes, especially a programmable [usually] electronic machine that performs high-speed mathematical or logical operations or that assembles, stores, correlates, or otherwise processes information.”[106] Any device which processes information qualifies as a computer, especially if the processing ispurposeful.[citation needed]

    Future

    There is active research to make computers out of many promising new types of technology, such asoptical computers, DNA computers, neural computers, and quantum computers. Most computers areuniversal, and are able to calculate any computable function, and are limited only by their memory capacity and operating speed. However different designs of computers can give very different performance for particular problems; for example quantum computers can potentially break some modern encryption algorithms (byquantum factoring) very quickly.

    Computer architecture paradigms

    There are many types of computer architectures:

    • Quantum computer vs. Chemical computer
    • Scalar processor vs. Vector processor
    • Non-Uniform Memory Access (NUMA) computers
    • Register machine vs. Stack machine
    • Harvard architecture vs. von Neumann architecture
    • Cellular architecture

    Of all theseabstract machines, a quantum computer holds the most promise for revolutionizing computing.[107] Logic gates are a common abstraction which can apply to most of the abovedigital or analog paradigms. The ability to store and execute lists of instructions called programs makes computers extremely versatile, distinguishing them fromcalculators. The Church–Turing thesis is a mathematical statement of this versatility: any computer with a minimum capability (being Turing-complete) is, in principle, capable of performingthe same tasks that any other computer can perform. Therefore, any type of computer (netbook, supercomputer, cellular automaton, etc.) is able to perform the same computational tasks, given enough time and storagecapacity.

    Artificial intelligence

    A computer will solve problems in exactly the way it is programmed to, without regard to efficiency, alternative solutions, possible shortcuts, or possible errors in the code. Computer programs that learn and adapt are part of the emerging field of artificial intelligence andmachine learning. Artificial intelligence based products generally fall into two major categories: rule-based systems and pattern recognition systems. Rule-based systems attempt torepresent the rules used by human experts and tend to be expensive to develop. Pattern-based systems use data about a problem to generate conclusions. Examples of pattern-based systems include voice recognition, font recognition, translation and the emerging field of on-line marketing.

    Professions and organizations

    As the use ofcomputers has spread throughout society, there are an increasing number of careers involving computers.

    Computer-related professions

    Hardware-related Electrical engineering, Electronic engineering, Computer engineering,Telecommunications engineering, Optical engineering, Nanoengineering
    Software-related Computer science, Computer engineering, Desktop publishing, Human–computer interaction, Information technology, Information systems, Computational science,Software engineering, Video game industry, Web design

    The need for computers to work well together and to be able to exchange information has spawned the need for many standards organizations, clubs and societies of both a formal and informal nature.

    Organizations

    Standards groups ANSI, IEC, IEEE,IETF, ISO, W3C
    Professional societies ACM, AIS, IET,IFIP, BCS
    Free/open source software groups Free Software Foundation, Mozilla Foundation, Apache Software Foundation

    See also

    • Glossary of computers
    • Computability theory
    • Computer security
    • Glossary of computer hardware terms
    • History of computer science
    • List of computer termetymologies
    • List of fictional computers
    • List of pioneers in computer science
    • Pulse computation
    • TOP500 (list of most powerful computers)
    • Unconventional computing

    Notes

  • ^ According toSchmandt-Besserat 1981, these clay containers contained tokens, the total of which were the count of objects being transferred. The containers thus served as something of a bill of lading or an accounts book. In order to avoid breaking open the containers, first, clay impressions of the tokens wereplaced on the outside of the containers, for the count; the shapes of the impressions were abstracted into stylized marks; finally, the abstract marks were systematically used as numerals; these numerals were finally formalized as numbers.Eventually the marks on the outside of the containers were all that were needed to convey the count, and the clay containers evolved into clay tablets with marks for the count.Schmandt-Besserat 1999 estimates it took 4000 years.
  • ^ The Intel 4004 (1971) die was 12 mm2, composed of 2300 transistors; by comparison, the Pentium Pro was 306 mm2, composed of 5.5 milliontransistors.[87]
  • ^ Most major 64-bit instruction set architectures are extensions of earlier designs. All of the architectures listed in this table,except for Alpha, existed in 32-bit forms before their 64-bit incarnations were introduced.
  • ^ The control unit’s role in interpreting instructions has varied somewhat in the past. Although the control unit is solely responsible for instruction interpretation in most modern computers, this is not always the case. Some computers have instructions that arepartially interpreted by the control unit with further interpretation performed by another device. For example, EDVAC, one of the earliest stored-program computers, used a central control unit that interpreted only four instructions. All of the arithmetic-related instructions were passed on to its arithmetic unit and further decoded there.
  • ^ Instructions often occupy more than one memory address, therefore the program counter usually increases by the number of memory locations required to store one instruction.
  • ^ Flash memory also may only be rewritten a limited number of times before wearing out,making it less useful for heavy random access usage.[94]
  • ^ However, it is also very common to construct supercomputers out of many pieces of cheap commodity hardware; usually individual computersconnected by networks. These so-called computer clusters can often provide supercomputer performance at a much lower cost than customized designs. While custom architectures are still used for most of the most powerful supercomputers, there has been a proliferation of cluster computers in recentyears.[99]
  • ^ Even some later computers were commonly programmed directly in machine code. Some minicomputers like the DECPDP-8 could be programmed directly from a panel of switches. However, this method was usually used only as part of the booting process. Most modern computers boot entirely automatically by reading a boot program from somenon-volatile memory.
  • ^ However, there is sometimes some form of machine language compatibility between different computers. An x86-64 compatible microprocessor like theAMD Athlon 64 is able to run most of the same programs that an Intel Core 2 microprocessor can, as well as programs designed for earlier microprocessors like the IntelPentiums and Intel 80486. This contrasts with very early commercial computers, which were often one-of-a-kind and totally incompatible with other computers.
  • ^ High level languagesare also often interpreted rather than compiled. Interpreted languages are translated into machine code on the fly, while running, by another program called an interpreter.
  • ^ It is not universally true that bugs are solely due to programmer oversight. Computer hardware may fail or may itself have a fundamental problem that produces unexpected results in certain situations. For instance, the Pentium FDIV bug caused someIntel microprocessors in the early 1990s to produce inaccurate results for certain floating point division operations. This was caused by a flaw in the microprocessor design and resulted in a partialrecall of the affected devices.
  • ^ According to the Shorter Oxford English Dictionary (6th ed, 2007), the word computer dates back to the mid 17th century, when it referred to “A person who makes calculations;specifically a person employed for this in an observatory etc.”
  • References

  • ^ Evans 2018, p. 23.
  • ^a b Smith 2013, p. 6.
  • ^ “computer (n.)”. Online Etymology Dictionary. Archived from the original on 16 November 2016. Retrieved 19 August 2021.
  • ^Robson, Eleanor (2008), Mathematics in Ancient Iraq, p. 5, ISBN 978-0-691-09182-2: calculi were in use in Iraq forprimitive accounting systems as early as 3200–3000 BCE, with commodity-specific counting representation systems. Balanced accounting was in use by 3000–2350 BCE, and a sexagesimal number system was in use 2350–2000 BCE.
  • ^Flegg, Graham. (1989). Numbers through the ages (1st ed.). Houndmills, Basingstoke, Hampshire: Macmillan Education. ISBN 0-333-49130-0.OCLC 24660570.{{cite book}}: CS1 maint:date and year (link)
  • ^ The Antikythera Mechanism Research ProjectArchived 28 April 2008 at the Wayback Machine, The Antikythera Mechanism Research Project. Retrieved 1 July 2007.
  • ^ Marchant, Jo (1 November 2006). “In search of lost time”. Nature. 444 (7119): 534–538.Bibcode:2006Natur.444..534M. doi:10.1038/444534a.PMID 17136067. S2CID 4305761.Archived from the original on 16 December 2021. Retrieved 12 March2022.
  • ^ G. Wiet, V. Elisseeff, P. Wolff, J. Naudu (1975). History of Mankind, Vol 3: The Great medieval Civilisations, p. 649. George Allen & Unwin Ltd, UNESCO.
  • ^ Fuat Sezgin “Catalogue of the Exhibition of the Institute for the History of Arabic-Islamic Science (at the Johann Wolfgang Goethe University”, Frankfurt, Germany) Frankfurt Book Fair 2004, pp. 35 & 38.
  • ^ Charette, François(2006). “Archaeology: High tech from Ancient Greece”. Nature. 444 (7119): 551–552. Bibcode:2006Natur.444..551C.doi:10.1038/444551a. PMID 17136077.S2CID 33513516.
  • ^ Bedini, Silvio A.; Maddison, Francis R. (1966). “Mechanical Universe: The Astrarium of Giovanni de’ Dondi”. Transactions of the American Philosophical Society. 56 (5): 1–69.doi:10.2307/1006002. JSTOR 1006002.
  • ^ Price, Derek de S. (1984). “A History of Calculating Machines”. IEEE Micro. 4 (1): 22–52.doi:10.1109/MM.1984.291305.
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  • ^“The Writer Automaton, Switzerland”. chonday.com. 11 July 2013. Archived from the original on 20 February 2015. Retrieved 28 January2015.
  • ^a b Ray Girvan, “The revealed grace of the mechanism: computing after Babbage”Archived 3 November 2012 at the Wayback Machine, Scientific Computing World, May/June 2003
  • ^Halacy, Daniel Stephen (1970). Charles Babbage, Father of the Computer. Crowell-Collier Press. ISBN 978-0-02-741370-0.
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    External links

    [/lightweight-accordion]

    What is the short definition of a computer?

    What is a computer for answer? : A computer is an electronic device that manipulates information, or data It has the ability to store, retrieve, and process data You may already know that you can use a computer to type documents, send email, play games, and browse the Web
    What is a computer best definition? : computer / (kmpjut) / noun a device, usually electronic, that processes data according to a set of instructions The digital computer stores data in discrete units and performs arithmetical and logical operations at very high speed
    [lightweight-accordion title=”Read Detail Answer On What is a computer best definition?”]

    READ  The Python For Loop: How to Use It Easily and effectively

    A computer is a device that acceptsinformation(in the form ofdigitalizeddata) and manipulates it for some result based on aprogram, software,or sequence of instructions on how the data is to be processed

    Complex computers have the capability of temporarily storing data, including programs, which are also data. One or more programs may be provided to the computer (loaded into its storage and then launched by an administrator or user), or a program may be constant and built into the hardware of the computer (and known as logic circuitry, as it is on microprocessors). Both types of programming are present in modern computers.

    Analog computer – represents data by measurable quantities Desktop computer – a personal computer that fits on a desk and is often used for business or gaming Digital computer – operates with numbers expressed as digits Hybrid computer – combines features of both analog and digital computers Laptop (notebook) – an easilytransported computer that is smaller than a briefcase Mainframe (big iron) computer – a centralized computer used for large scale computing Microcomputer – generally referred to as a PC (personal computer). Uses a single integrated semiconductor chip microprocessor. minicomputer -an antiquated term for a computer that is smaller than a mainframe and larger than a microcomputer Netbook – a smaller and less powerful version of a laptopPersonal computer (PC) – a digital computer designed to be used by one person at a timeSmartphone- a cellular telephone designed with an integrated computer Supercomputer – a high performing computer that operates at extremely high speeds Tablet computer (tablet PC) – a wireless personal computer with a touch screenWorkstation – equipment designed for a single user to complete a specialized technical/scientific task

    History of the modern computer

    Most histories of the modern computer begin with theAnalytical Engineenvisioned byCharles Babbagefollowing the mathematical ideas ofGeorge Boole, the mathematician who first stated the principles of logic inherent in today’s digital computer Babbage’s assistant and collaborator,Ada Lovelace,is said to have introduced the ideas of program loops and subroutines and is sometimes considered the first programmer Apart from mechanical calculators, the first really useable computers began with thevacuum tube, accelerated with the invention of thetransistor, which then became embedded in large numbers in integrated circuits, ultimately making possible the relatively low-cost personalcomputer

    The principles of the stored program developed by John von Neumann in 1945 are fundamental to all modern computers. Basically, the computer reads each instruction in the program one at a time, executes the operation, and then reads the next instruction.

    From the mid-1900s to the present, the advancement of computers is divided into five generations. While the year spanfor each generation varies depending on the reference source, the most recognized generational timeline is below.

    1940 to 1956

    First generation computers were room-sized machines that used vacuum tubes for circuitry and magnetic drums for limited internal storage. These machines used punched cards for data inputand a binary machine code (language). Examples of first generation computers include the ABC (Atanasoff Berry Computer), Colossus, IBM 650 and the EDVAC (Electronic Discrete Variable Computer).

    1956 to 1963

    Second generation computers replaced vacuum tubes with transistors, usedmagnetic tape storage for increased storage capacity, used BAL (basic assembler language) and continued to use punched cards for input. Transistors drew less power and generated less heat than vacuum tubes. Examples of second-generation computers include theIBM 7090, IBM 7094, IBM 1400, and the UNIVAC (Universal Automatic Computer).

    1964 to 1971

    Third generation computers used ICs (integrated circuits) with several transistors and MOS (metal oxidesemiconductor) memory. Smaller, cheaper and faster than their predecessors, these computers used keyboards for input, monitors for output, and employed programming languages such as FORTRAN (Formula Translation),COBOL (Common Business Oriented Language) and C-Language. Examples of third generation computers include the IBM 360 and IBM 370 series.

    1972 to 2010

    Fourth generation computers used integratedcircuits and microprocessors with VLSI (very large scale integration), RAM (random access memory), ROM (read-only memory), and high-level programming languages including C and C++. The creation and expansion of theWorld Wide Web and cloud computing (the ability to deliver hosted services using the Internet) significantly enhanced computing capabilities during this period. Examples of fourth generation computers include Apple’s Macintoshand IBM’s PC.

    2010 and beyond

    Artificial intelligence (AI) is the foundation of fifth generation computers, which employ large-scale integrated chips and multiple CPUs (processors). Fifth-generation computers are capable of speaking back to users in natural language, solving extremely difficult problems, and coming to logical, human-like conclusions. They also use quantum computing and nanotechnology (molecular manufacturing) to manufacture molecules. Numerous programs (and computers) can work simultaneously and in parallel on the same problem thanks to fifth generation computers and software.

    The advent of the Internet, cloud computing, and highbandwidthdata transmission enables programs and data to be distributed over a network quickly and efficiently, while application programs and software make computers the tools of choice for such thingsasword processing, databases, spreadsheets, presentations, ERP (enterprise resource planning),simulations, education, CMS (content management systems), gamingand engineering

    This was last updated in April 2019

    Continue Reading About computer

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    • A computer history museum guide.
    • Computer [email protected]: What was happening in IT in April over the years.
    • The history of computers: A brief timeline.
    • What to expect from IoT, the technology of the future.

    Dig Deeper on IT operations and infrastructure management

    • Transistor

      By: Rahul Awati

    • metal-oxide semiconductor field-effect transistor (MOSFET)

      By: Gavin Wright

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      By: TechTarget Contributor

    • amplifier

      By: TechTarget Contributor

    [/lightweight-accordion]What are the 5 definition of computer? : (1) A class of machine that acts on data as opposed to physical things (2) Machines that process meaning represented as symbols (3) General purpose devices for performing calculations and operations on data (4) Programmable machines for storing, processing and calculating data
    [lightweight-accordion title=”Read Detail Answer On What are the 5 definition of computer?”]

    A computer is a device that accepts information (in the form of digitalized data) and manipulates it in accordance with a program, software, or set of instructions on how the data is to be processed in order to produce a particular result.

    Complex computers come equipped with tools for temporarily storing data, including programs, which are also data. One or more programs may be provided to the computer (loaded into its storage and then launched by an administrator or user), or a program may be constant and built into the hardware of the computer (and known as logic circuitry, as it is on microprocessors). Both types of programming are present in computers today.

    Analog computer – represents data by measurable quantities Desktop computer – a personal computer that fits on a desk and is often used for business or gaming Digital computer – operates with numbers expressed as digits Hybrid computer – combines features of both analog and digital computers Laptop (notebook) – an easilytransported computer that is smaller than a briefcase Mainframe (big iron) computer – a centralized computer used for large scale computing Microcomputer – generally referred to as a PC (personal computer). Uses a single integrated semiconductor chip microprocessor. minicomputer -an antiquated term for a computer that is smaller than a mainframe and larger than a microcomputer Netbook – a smaller and less powerful version of a laptopPersonal computer (PC) – a digital computer designed to be used by one person at a timeSmartphone- a cellular telephone designed with an integrated computer Supercomputer – a high performing computer that operates at extremely high speeds Tablet computer (tablet PC) – a wireless personal computer with a touch screenWorkstation – equipment designed for a single user to complete a specialized technical/scientific task

    History of the modern computer

    Most histories of the modern computer begin with theAnalytical Engineenvisioned byCharles Babbagefollowing the mathematical ideas ofGeorge Boole, the mathematician who first stated the principles of logic inherent in today’s digital computer Babbage’s assistant and collaborator,Ada Lovelace,is said to have introduced the ideas of program loops and subroutines and is sometimes considered the first programmer Apart from mechanical calculators, the first really useable computers began with thevacuum tube, accelerated with the invention of thetransistor, which then became embedded in large numbers in integrated circuits, ultimately making possible the relatively low-cost personalcomputer

    Modern computers inherently follow the ideas of the stored program laid out byJohn von Neumannin 1945 Essentially, the program is read by the computer one instruction at a time, an operation is performed, and the computer then reads the next instruction

    From the mid-1900s to the present, the advancement of computers is divided into five generations. While the year spanfor each generation varies depending on the reference source, the most recognized generational timeline is below.

    1940 to 1956

    First generation computers were room-sized machines that used vacuum tubes for circuitry and magnetic drums for limited internal storage. These machines used punched cards for data inputand a binary machine code (language). Examples of first generation computers include the ABC (Atanasoff Berry Computer), Colossus, IBM 650 and the EDVAC (Electronic Discrete Variable Computer).

    1956 to 1963

    Second generation computers replaced vacuum tubes with transistors, usedmagnetic tape storage for increased storage capacity, used BAL (basic assembler language) and continued to use punched cards for input. Transistors drew less power and generated less heat than vacuum tubes. Examples of second-generation computers include theIBM 7090, IBM 7094, IBM 1400, and the UNIVAC (Universal Automatic Computer).

    1964 to 1971

    Third generation computers used ICs (integrated circuits) with several transistors and MOS (metal oxidesemiconductor) memory. Smaller, cheaper and faster than their predecessors, these computers used keyboards for input, monitors for output, and employed programming languages such as FORTRAN (Formula Translation),COBOL (Common Business Oriented Language) and C-Language. Examples of third generation computers include the IBM 360 and IBM 370 series.

    1972 to 2010

    Fourth generation computers used integratedcircuits and microprocessors with VLSI (very large scale integration), RAM (random access memory), ROM (read-only memory), and high-level programming languages including C and C++. The creation and expansion of theWorld Wide Web and cloud computing (the ability to deliver hosted services using the Internet) significantly enhanced computing capabilities during this period. Examples of fourth generation computers include Apple’s Macintoshand IBM’s PC.

    2010 and beyond

    Fifth generation computers are based on AI (artificial intelligence), use large scale integrated chips and more than one CPU (processor) Fifth generation computers respond tonatural language input, solve highly complex problems, make decisions through logical (human-like) reasoning and use quantum computing and Nanotechnology (molecular manufacturing) Fifth generation computers and programs allow multiple programs (and computers) to work on the same problem at the same time in parallel

    With the development of the Internet, cloud computing, and high-bandwidth data transmission, it is now possible to distribute programs and data over a network quickly and effectively. Additionally, application software and programs have turned computers into the preferred tools for tasks like word processing, databases, spreadsheets, presentations, ERP (enterprise resource planning), simulations, education, CMS (content management systems), gaming, and engineering.

    This was last updated in April 2019

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    Additional Question — What is the short definition of a computer?

    What are the 7 types of computers?

    Contents1 Supercomputer. (2) Mainframe. Three server computers. 4 Computer Workstation. Five Personal Computers or PCs. 6 Microprocessor. Phone number 7. 8 references.

    What is computer and its types?

    The computer types. No. Type of Computer1Personal Computer (PC)2Workstation3Minicomputer4″Main Frame””””””””””””””””””””””””””””

    What is computer definition for Class 4?

    Ans A computer system is defined as a machine that is used to generate information from data It consist of four types of devices: Input devices, Processing device, Output devices, Storage devices

    What is computer explain in 500 words?

    The Computer is an electronic calculating machine It is very simple data based machine It performs various functions faster and more accurately It can be used to do any kind of work It provides facility of many other tools like paint tool, text tool etc which are very beneficial to us

    What is computer definition for Class 1?

    A computer is an electronic tool that can accept data (input), process the data in accordance with predetermined rules, produce information (output), and store the information for later use1. Computer functions.

    What is the four types of computer?

    Supercomputer is one of the four basic types of computers. The mainframe computer. Minicomputer. An analog computer. Digitized computer. hybrid computer

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