Further topics

Hardware
Main article: Computer hardware

The term hardware covers all of those parts of a computer that are tangible objects. Circuits, displays, power supplies, cables, keyboards, printers and mice are all hardware.
History of computing hardware First Generation (Mechanical/Electromechanical) Calculators Antikythera mechanism, Difference Engine, Norden bombsight
Programmable Devices Jacquard loom, Analytical Engine, Harvard Mark I, Z3
Second Generation (Vacuum Tubes) Calculators Atanasoff–Berry Computer, IBM 604, UNIVAC 60, UNIVAC 120
Programmable Devices Colossus, ENIAC, Manchester Small-Scale Experimental Machine, EDSAC, Manchester Mark 1, 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, System/360, BUNCH
Minicomputer PDP-8, PDP-11, System/32, System/36
Fourth Generation (VLSI integrated circuits) Minicomputer VAX, IBM System i
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 architecture
64-bit microcomputer[28] Alpha, MIPS, PA-RISC, PowerPC, SPARC, x86-64
Embedded computer Intel 8048, Intel 8051
Personal computer Desktop computer, Home computer, Laptop computer, Personal digital assistant (PDA), Portable computer, Tablet computer, Wearable computer
Theoretical/experimental Quantum computer, Chemical computer, DNA computing, Optical computer, Spintronics based computer
Other Hardware Topics Peripheral device (Input/output) Input Mouse, Keyboard, Joystick, Image scanner
Output Monitor, Printer
Both Floppy disk drive, Hard disk, Optical disc drive, Teleprinter
Computer busses Short range RS-232, SCSI, PCI, USB
Long range (Computer networking) Ethernet, ATM, FDDI



Software
Main article: Computer software

Software refers to parts of the computer which do not have a material form, such as programs, data, protocols, etc. When software is stored in hardware that cannot easily be modified (such as BIOS ROM in an IBM PC compatible), it is sometimes called "firmware" to indicate that it falls into an uncertain area somewhere between hardware and software.
Computer software Operating system Unix and BSD UNIX System V, AIX, HP-UX, Solaris (SunOS), IRIX, List of BSD operating systems
GNU/Linux List of Linux distributions, Comparison of Linux distributions
Microsoft Windows Windows 95, Windows 98, Windows NT, Windows 2000, Windows XP, Windows Vista, Windows CE
DOS 86-DOS (QDOS), PC-DOS, MS-DOS, FreeDOS
Mac OS Mac OS classic, Mac OS X
Embedded and real-time List of embedded operating systems
Experimental Amoeba, Oberon/Bluebottle, Plan 9 from Bell Labs
Library Multimedia DirectX, OpenGL, OpenAL
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
Text-based user interface Command-line interface, Text user interface
Application Office suite Word processing, Desktop publishing, Presentation program, Database management system, Scheduling & Time management, Spreadsheet, Accounting software
Internet Access Browser, E-mail 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, Audio synthesis, Computer music
Software Engineering Compiler, Assembler, Interpreter, Debugger, Text Editor, Integrated development environment, 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

Programming languages

Programming languages 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 machine language 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. There are thousands of different programming languages—some intended to be general purpose, others useful only for highly specialized applications.
Programming Languages Lists of programming languages Timeline of programming languages, Categorical list of programming languages, Generational list of programming languages, Alphabetical list of programming languages, Non-English-based programming languages
Commonly used Assembly languages ARM, MIPS, x86
Commonly used High level languages Ada, BASIC, C, C++, C#, COBOL, Fortran, Java, Lisp, Pascal, Object Pascal
Commonly used Scripting languages Bourne script, JavaScript, Python, Ruby, PHP, Perl

Professions and organizations

As the use of computers has spread throughout society, there are an increasing number of careers involving computers. Following the theme of hardware, software and firmware, the brains of people who work in the industry are sometimes known irreverently as wetware or "meatware".
Computer-related professions Hardware-related Electrical engineering, Electronics engineering, Computer engineering, Telecommunications engineering, Optical engineering, Nanoscale engineering
Software-related Computer science, Human-computer interaction, Information technology, Software engineering, Scientific computing, Web design, Desktop publishing

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, ACM Special Interest Groups, IET, IFIP
Free/Open source software groups Free Software Foundation, Mozilla Foundation, Apache Software Foundation

See also
Sister project Look up computer in
Wiktionary, the free dictionary.
Sister project Wikiquote has a collection of quotations related to: Computers
Sister project Wikimedia Commons has media related to: Computer
Sister project Wikiversity has learning materials about Introduction to Computers

* Computability theory
* Computer science
* Computing
* Computers in fiction
* Computer security and Computer insecurity
* Electronic waste
* List of computer term etymologies
* Virtualization


External links

* Computer mini-article

Notes

1. ^ In 1946, ENIAC consumed an estimated 174 kW. By comparison, a typical personal computer may use around 400 W; over four hundred times less. (Kempf 1961)
2. ^ Early computers such as Colossus and ENIAC were able to process between 5 and 100 operations per second. A modern "commodity" microprocessor (as of 2007) can process billions of operations per second, and many of these operations are more complicated and useful than early computer operations.
3. ^ "Heron of Alexandria". http://www.mlahanas.de/Greeks/HeronAlexandria2.htm. Retrieved on 2008-01-15.
4. ^ a b Ancient Discoveries, Episode 11: Ancient Robots, History Channel, http://www.youtube.com/watch?v=rxjbaQl0ad8, retrieved on 2008-09-06
5. ^ Howard R. Turner (1997), Science in Medieval Islam: An Illustrated Introduction, p. 184, University of Texas Press, ISBN 0292781490
6. ^ Donald Routledge Hill, "Mechanical Engineering in the Medieval Near East", Scientific American, May 1991, pp. 64-9 (cf. Donald Routledge Hill, Mechanical Engineering)
7. ^ The Analytical Engine should not be confused with Babbage's difference engine which was a non-programmable mechanical calculator.
8. ^ B. Jack Copeland, ed., Colossus: The Secrets of Bletchley Park's Codebreaking Computers, Oxford University Press, 2006
9. ^ Lavington 1998, p. 37
10. ^ This program was written similarly to those for the PDP-11 minicomputer and shows some typical things a computer can do. All the text after the semicolons are comments for the benefit of human readers. These have no significance to the computer and are ignored. (Digital Equipment Corporation 1972)
11. ^ Attempts are often made to create programs that can overcome this fundamental limitation of computers. Software that mimics learning and adaptation is part of artificial intelligence.
12. ^ 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 some Intel 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 partial recall of the affected devices.
13. ^ Even some later computers were commonly programmed directly in machine code. Some minicomputers like the DEC PDP-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 some non-volatile memory.
14. ^ However, there is sometimes some form of machine language compatibility between different computers. An x86-64 compatible microprocessor like the AMD 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 Intel Pentiums and Intel 80486. This contrasts with very early commercial computers, which were often one-of-a-kind and totally incompatible with other computers.
15. ^ High level languages are also often interpreted rather than compiled. Interpreted languages are translated into machine code on the fly by another program called an interpreter.
16. ^ The control unit's rule in interpreting instructions has varied somewhat in the past. While the control unit is solely responsible for instruction interpretation in most modern computers, this is not always the case. Many computers include some instructions that may only be partially interpreted by the control system and partially interpreted by another device. This is especially the case with specialized computing hardware that may be partially self-contained. For example, EDVAC, the first modern stored program computer to be designed, used a central control unit that only interpreted four instructions. All of the arithmetic-related instructions were passed on to its arithmetic unit and further decoded there.
17. ^ Instructions often occupy more than one memory address, so the program counters usually increases by the number of memory locations required to store one instruction.
18. ^ David J. Eck (2000). The Most Complex Machine: A Survey of Computers and Computing. A K Peters, Ltd.. p. 54. ISBN 9781568811284.
19. ^ Erricos John Kontoghiorghes (2006). Handbook of Parallel Computing and Statistics. CRC Press. p. 45. ISBN 9780824740672.
20. ^ Flash memory also may only be rewritten a limited number of times before wearing out, making it less useful for heavy random access usage. (Verma 1988)
21. ^ Donald Eadie (1968). Introduction to the Basic Computer. Prentice-Hall. p. 12.
22. ^ Arpad Barna; Dan I. Porat (1976). Introduction to Microcomputers and the Microprocessors. Wiley. p. 85. ISBN 9780471050513.
23. ^ Jerry Peek; Grace Todino, John Strang (2002). Learning the UNIX Operating System: A Concise Guide for the New User. O'Reilly. p. 130. ISBN 9780596002619.
24. ^ Gillian M. Davis (2002). Noise Reduction in Speech Applications. CRC Press. p. 111. ISBN 9780849309496.
25. ^ However, it is also very common to construct supercomputers out of many pieces of cheap commodity hardware; usually individual computers connected 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 recent years. (TOP500 2006)
26. ^ Agatha C. Hughes (2000). Systems, Experts, and Computers. MIT Press. p. 161. ISBN 9780262082853. "The experience of SAGE helped make possible the first truly large-scale commercial real-time network: the SABRE computerized airline reservations system..."
27. ^ "A Brief History of the Internet". Internet Society. http://www.isoc.org/internet/history/brief.shtml. Retrieved on 2008-09-20.
28. ^ 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.

References

* a Kempf, Karl (1961). Historical Monograph: Electronic Computers Within the Ordnance Corps. Aberdeen Proving Ground (United States Army). http://ed-thelen.org/comp-hist/U-S-Ord-61.html.
* a Phillips, Tony (2000). "The Antikythera Mechanism I". American Mathematical Society. http://www.math.sunysb.edu/~tony/whatsnew/column/antikytheraI-0400/kyth1.html. Retrieved on 2006-04-05.
* a Shannon, Claude Elwood (1940). A symbolic analysis of relay and switching circuits. Massachusetts Institute of Technology. http://hdl.handle.net/1721.1/11173.
* a Digital Equipment Corporation (1972) (PDF). PDP-11/40 Processor Handbook. Maynard, MA: Digital Equipment Corporation. http://bitsavers.vt100.net/dec/www.computer.museum.uq.edu.au_mirror/D-09-30_PDP11-40_Processor_Handbook.pdf.
* a Verma, G.; Mielke, N. (1988). Reliability performance of ETOX based flash memories. IEEE International Reliability Physics Symposium.
* a Meuer, Hans; Strohmaier, Erich; Simon, Horst; Dongarra, Jack (2006-11-13). "Architectures Share Over Time". TOP500. http://www.top500.org/lists/2006/11/overtime/Architectures. Retrieved on 2006-11-27.
* Lavington, Simon (1998), A History of Manchester Computers (2 ed.), Swindon: The British Computer Society, ISBN 0902505018
* Stokes, Jon (2007). Inside the Machine: An Illustrated Introduction to Microprocessors and Computer Architecture. San Francisco: No Starch Press. ISBN 978-1-59327-104-6.