A computer is a programmable machine designed to sequentially and automatically carry out a sequence of arithmetic or logical operations. Conventionally a computer consists of some form of memory for data storage, at least one element that carries out arithmetic and logic operations, and a sequencing and control element that can change the order of operations based on the information that is stored. A computer's processing unit executes series of instructions that make it read, manipulate and then store data. Conditional instructions change the sequence of instructions as a function of the current state of the machine or its environment.
The first electronic computers were developed in the mid20th century (1940–1945).
Originally, they were the size of a large room, consuming as much power as several hundred modern personal computers (PCs). Modern computers based on integrated circuits are millions to billions of times more capable than the early machines, and occupy a fraction of the space. Simple computers are small enough to fit into mobile devices, and mobile computers can be powered by small batteries.
The first use of the word "computer" was recorded in 1613, referring to a person who carried out calculations, or computations, and the word continued with the same meaning until the middle of the 20th century.
The Jacquard loom, on display at the Museum of Science and Industry in Manchester, England, was one of the first programmable devices.
In 1801, Joseph Marie Jacquard made an improvement to the textile loom by introducing a series of punched paper cards as a template which allowed his loom to weave intricate patterns automatically. The resulting Jacquard loom was an important step in the development of computers because the use of punched cards to define woven patterns can be viewed as an early, albeit limited, form of program. This portrait of Jacquard was woven in silk on a Jacquard loom and required 24,000 punched cards to create (1839). It was only produced to order. Charles Babbage owned one of these portraits ; it inspired him in using perforated cards in his analytical engine
In 1837, Charles Babbage was the first to conceptualize and design a fully programmable mechanical computer, his analytical engine. 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. He gave a successful demonstration of its use in computing tables in 1906. This machine was given to the Science museum in South Kensington in 1910. In the late 1880s, Herman Hollerith invented the recording of data on a machine readable medium. Alan Turing is regarded as the father of modern computer science. In 1936 Turing provided an influential formalisation of the concept of the algorithm andcomputation with the Turing machine,
Which became operational in 1946, is considered to be the first general-purpose electronic computer.
Magnetic core memory was the computer memory of choice throughout the 1960s, until it was replaced by semiconductor memory.
Computer main memory comes in two principal varieties: random-access memory or RAM and read-only memory or ROM. RAM can be read and written to anytime the CPU commands it, but ROM is pre-loaded with data and software that never changes, so the CPU can only read from it. ROM is typically used to store the computer's initial startup instructions. In general, the contents of RAM are erased when the power to the computer is turned off, but ROM retains its data indefinitely. In a PC, the ROM contains a specialized program called the BIOS that loads the computer's operating system from the hard disk drive into RAM whenever the computer is turned on or reset.
I/O is the means by which a computer exchanges information with the outside world.Devices that provide input or output to the computer are called peripherals.
Hard disk drives are common storage devices used with computers.
Personal computer, peripherals include input devices like the keyboard and mouse. Output devices such as the display and printer.
History of computing hardware Calculators Antikythera mechanism, Difference engine, Norden bombsight Jacquard loom, Analytical engine, Harvard Mark I, Z3 Atanasoff–Berry Computer, IBM 604, UNIVAC 60, UNIVAC 120 Colossus, ENIAC, Manchester Small-Scale Experimental Machine, EDSAC, Manchester Mark 1, Ferranti Pegasus, Ferranti Mercury, CSIRAC, EDVAC, UNIVAC I, IBM 701, IBM 702, IBM 650, Z22 IBM 7090, IBM 7080, IBM System/360, BUNCH PDP-8, PDP-11, IBM System/32, IBM System/36 VAX, IBM System i Intel 4004, Intel 4040
First Generation (Mechanical/Electromechanical)
Programmable Devices Calculators
Second Generation (Vacuum Tubes) Programmable Devices
Third Generation (Discrete transistors and SSI, MSI, LSI Integrated circuits)
Quantum computer, Chemical computer, DNA computing,Optical computer, Spintronics based computer
Other Hardware Topics
Input
Mouse, Keyboard, Joystick, Image scanner, Webcam, Graphics tablet, Microphone Monitor, Printer, Loudspeak er Floppy disk drive, Hard disk drive, Optical disc drive, Teleprinter RS-232, SCSI, PCI, USB
Peripheral device (Input/output)
Output
Both
Short range Computer busses
Long range (Computer networking)
Ethernet, ATM, FDDI
Computer software Unix and BSD GNU/Linux UNIX System V, IBM AIX, HP-UX, Solaris (SunOS), IRIX, List of BSD operating systems List of Linux distributions, Comparison of Linux distributions Windows 95, Windows 98, Windows NT, Windows 2000, Windows XP, Windows Vista, Windows 7 86-DOS (QDOS), PC-DOS, MS-DOS, DR-DOS, FreeDOS Mac OS classic, Mac OS X List of embedded operating systems Amoeba, Oberon/Bluebottle, Plan 9 from Bell Labs DirectX, OpenGL, OpenAL C standard library, Standard Template Library TCP/IP, Kermit, FTP, HTTP, SMTP HTML, XML, JPEG, MPEG, PNG Microsoft Windows, GNOME, KDE, QNX Photon, CDE, GEM, Aqua Command-line interface, Text user interface Word processing, Desktop publishing, Presentation program, Database management system, Scheduling & Time management, Spreadsheet, Accounting software Browser, E-mail client, Web server, Mail transfer agent, Instant messaging Computer-aided design, Computer-aided manufacturing, Plant management, Robotic manufacturing, Supply chain management Raster graphics editor, Vector graphics editor, 3D modeler, Animation editor, 3D computer graphics, Video editing, Image processing Digital audio editor, Audio playback, Mixing, Audio synthesis, Computer music Compiler, Assembler, Interpreter, Debugger, Text editor, Integrated development environment, Software performance analysis, Revision control, Software configuration management Edutainment, Educational game, Serious game, Flight simulator Strategy, Arcade, Puzzle, Simulation, First-person shooter, Platform, Massively multiplayer, Interactive fiction Artificial intelligence, Antivirus software, Malware scanner, Installer/Package management systems, File manager
Operating system
Microsoft Windows
DOS Mac OS Embedded and real-time Experimental Multimedia
Library
Programming library Protocol File format Graphical user interface(WIMP)
Data
User interface Text-based user interface
Office suite
Internet Access
Design and manufacturing
Graphics Application
Audio
Software engineering
Educational Games
Misc
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