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Information technology (IT) can be defined in various ways, but is broadly considered to encompass the use of computers and telecommunications equipment to store, retrieve, transmit and manipulate data.[1] The term is commonly used as a synonym for computers and computer networks, but it also encompasses other information distribution technologies such as television and telephones.[2]

Humans have been storing, retrieving, manipulating and communicating information since the Sumerians in Mesopotamia developed writing in about 3000?BC,[3] but the term "information technology" in its modern sense first appeared in a 1958 article published in the Harvard Business Review; authors Leavitt and Whisler commented that "the new technology does not yet have a single established name. We shall call it information technology (IT)."[4] Based on the storage and processing technology employed, it is possible to distinguish four distinct phases of IT development: pre-mechanical (3000?BC?? 1450?AD), mechanical (1450?1840), electromechanical (1840?1940) and electronic.[3] This article focuses on the latter of those periods, which began in about 1940.

## Definitions[edit]

In a business context, the Information Technology Association of America has defined information technology (IT) as "the study, design, development, application, implementation, support or management of computer-based information systems".[5] In an academic context, the Association for Computing Machinery defines it as "undergraduate degree programs that prepare students to meet the computer technology needs of business, government, healthcare, schools, and other kinds of organizations?.... IT specialists assume responsibility for selecting hardware and software products appropriate for an organization, integrating those products with organizational needs and infrastructure, and installing, customizing, and maintaining those applications for the organization?s computer users. Examples of these responsibilities include the installation of networks; network administration and security; the design of web pages; the development of multimedia resources; the installation of communication components; the oversight of email systems; and the planning and management of the technology lifecycle by which an organization?s technology is maintained, upgraded, and replaced."[6]

## History of computers[edit]

Main article: History of computing hardware

Devices have been used to aid computation for thousands of years, probably initially in the form of a tally stick.[7] The Antikythera mechanism, dating from about the beginning of the first century BC, is generally considered to be the earliest known mechanical analog computer; it is also the earliest known geared mechanism.[8] Comparable geared devices did not emerge in Europe until the 16th century,[9] and it was not until 1645 that the first mechanical calculator capable of performing the four basic arithmetical operations was developed.[10]

Electronic computers, using either relays or valves, began to appear in the early 1940s. The electromechanical Zuse Z3, completed in 1941, was the world's first programmable computer, and by modern standards one of the first machines that could be considered a complete computing machine. Colossus, developed during the Second World War to decrypt German messages was the first electronic digital computer, but although programmable it was not general-purpose, being designed for a single task. Neither did it store its programs in memory; programming was carried out using plugs and switches to alter the internal wiring.[11] The first recognisably modern electronic digital stored-program computer was the Manchester Small-Scale Experimental Machine (SSEM), which ran its first program on 21 June 1948.[12]

## Data storage[edit]

Main article: Data storage device

Early electronic computers such as Colossus made use of punched tape, a long strip of paper on which data was represented by a series of holes, a technology now obsolete.[13] Electronic data storage as used in modern computers dates from the Second World War, when a form of delay line memory was developed to remove the clutter from radar signals, the first practical application of which was the mercury delay line.[14] The first random-access digital storage device was the Williams tube, based on a standard cathode ray tube,[15] but the information stored in it and delay line memory was volatile in that it had to be continuously refreshed, and thus was lost once power was removed. The earliest form of non-volatile computer storage was the magnetic drum, invented in 1932[16] and used in the Ferranti Mark 1, the world's first commercially available general-purpose electronic computer.[17]

Most digital data today is still stored magnetically on devices such as hard disk drives, or optically on media such as CD-ROMs.[18] It has been estimated that the worldwide capacity to store information on electronic devices grew from less than 3 exabytes in 1986 to 295 exabytes in 2007,[19] doubling roughly every 3?years.[20]

## Databases[edit]

Main article: Database management system

Database management systems emerged in the 1960s to address the problem of storing and retrieving large amounts of data accurately and quickly. One of the earliest such systems was IBM's Information Management System (IMS),[21] which is still widely deployed more than 40 years later.[22] IMS stores data hierarchically,[21] but in the 1970s Ted Codd proposed an alternative relational storage model based on set theory and predicate logic and the familiar concepts of tables, rows and columns. The first commercially available relational database management system (RDBMS) was available from Oracle in 1980.[23]

All database management systems consist of a number of components that together allow the data they store to be accessed simultaneously by many users while maintaining its integrity. A characteristic of all databases is that the structure of the data they contain is defined and stored separately from the data itself, in a database schema.[21]

The extensible markup language (XML) has become a popular format for data representation in recent years. Although XML data can be stored in normal file systems, it is commonly held in relational databases to take advantage of their "robust implementation verified by years of both theoretical and practical effort".[24] As an evolution of the Standard Generalized Markup Language (SGML), XML's text-based structure offers the advantage of being both machine and human-readable.[25]

## Data retrieval[edit]

The relational database model introduced a programming language independent Structured Query Language (SQL), based on relational algebra.[23]

The terms "data" and "information" are not synonymous. Anything stored is data, but it only becomes information when it is organised and presented meaningfully.[26] Most of the world's digital data is unstructured, and stored in a variety of different physical formats[27][a] even within a single organisation. Data warehouses began to be developed in the 1980s to integrate these disparate stores. They typically contain data extracted from various sources, including external sources such as the Internet, organised in such a way as to facilitate decision support systems (DSS).[28]

## Data transmission[edit]

Data transmission has three aspects: transmission, propagation, and reception.[29]

XML has been increasingly employed as a means of data interchange since the early 2000s,[30] particularly for machine-oriented interactions such as those involved in web-oriented protocols such as SOAP,[25] describing "data-in-transit rather than?... data-at-rest".[30] One of the challenges of such usage is converting data from relational databases into XML Document Object Model (DOM) structures.[31]

## Data manipulation[edit]

Hilbert and Lopez[19] identify the exponential pace of technological change (a kind of Moore's law): machines' application-specific capacity to compute information per capita roughly doubled every 14 months between 1986 and 2007; the per capita capacity of the world's general-purpose computers doubled every 18 months during the same two decades; the global telecommunication capacity per capita doubled every 34 months; the world's storage capacity per capita required roughly 40 months to double (every 3 years); and per capita broadcast information has doubled every 12.3 years.[19]

Massive amounts of data are stored worldwide every day, but unless it can be analysed and presented effectively it essentially resides in what have been called data tombs: "data archives that are seldom visited".[32] To address that issue, the field of data mining?? "the process of discovering interesting patterns and knowledge from large amounts of data"[33]?? emerged in the late 1980s.[34]

## Commercial perspective[edit]

Worldwide IT spending forecast[35] (billions of U.S. dollars)
Category | 2011 spending | 2012 spending
--- | --- | ---
Computing hardware | 404 | 420
Enterprise software | 269 | 281
IT services | 845 | 864
Telecom equipment | 340 | 377
Telecom services | 1,663 | 1,686
Total | 3,523 | 3,628

## Social and ethical perspectives[edit]

Main article: Information ethics

The field of information ethics was established by mathematician Norbert Wiener in the 1940s.[36] Some of the ethical issues associated with the use of information technology include:[37]

- Breaches of copyright by those downloading files stored without the permission of the copyright holders
- Employers monitoring their employees' emails and other Internet usage
- Unsolicited emails
- Hackers accessing online databases
- Web sites installing cookies or spyware to monitor a user's online activities

## See also[edit]

- Information systems (IS)

## References[edit]

Notes

1. ^ "Format" refers to the physical characteristics of the stored data such as its encoding scheme; "structure" describes the organisation of that data.

Citations

1. ^ Daintith, John, ed. (2009), "IT", A Dictionary of Physics, Oxford University Press, retrieved 1 August 2012 (subscription required)
2. ^ Chandler, Daniel; Munday, Rod, "Information technology", A Dictionary of Media and Communication (first ed.), Oxford University Press, retrieved 1 August 2012 (subscription required)
3. ^ a b Butler, Jeremy G., "A History of Information Technology and Systems", University of Arizona, retrieved 2?August 2012 Check date values in: `|accessdate=` (help)
4. ^ Leavitt, Harold J.; Whisler, Thomas L. Whisler (1958), "Management in the 1980s", Harvard Business Review 11
5. ^ Proctor 2011, preface.
6. ^ The Joint Task Force for Computing Curricula 2005. Computing Curricula 2005: The Overview Report (pdf)
7. ^ Schmandt-Besserat, D. (1981), "Decipherment of the earliest tablets", Science 211 (4479): 283?285, doi:10.1126/science.211.4479.283, PMID 17748027 `|accessdate=` requires `|url=` (help) (subscription required)
8. ^ Wright 2012, p. 279
9. ^ Childress 2000, p. 94
10. ^ Chaudhuri 2004, p. 3
11. ^ Lavington 1980
12. ^ Enticknap, Nicholas (Summer 1998), "Computing's Golden Jubilee", Resurrection (The Computer Conservation Society) (20), ISSN 0958-7403, retrieved 19?April 2008 Check date values in: `|accessdate=` (help)
13. ^ Alavudeen & Venkateshwaran 2010, p. 178
14. ^ Lavington 1998, p. 1
15. ^ "Early computers at Manchester University", Resurrection (The Computer Conservation Society) 1 (4), Summer 1992, ISSN 0958-7403, retrieved 19?April 2008 Check date values in: `|accessdate=` (help)
16. ^ Universit?t Klagenfurt (ed.), "Magnetic drum", Virtual Exhibitions in Informatics, retrieved 21?August 2011 Check date values in: `|accessdate=` (help)
17. ^ The Manchester Mark 1, University of Manchester, retrieved 24?January 2009 Check date values in: `|accessdate=` (help)
18. ^ Wang & Taratorin 1999, pp. 4?5.
19. ^ a b c Hilbert, Martin; L?pez, Priscilla, "The World's Technological Capacity to Store, Communicate, and Compute Information", Science 332 (6025): 60?65, retrieved 1 August 2012
20. ^ "video animation on The World's Technological Capacity to Store, Communicate, and Compute Information from 1986 to 2010
21. ^ a b c Ward & Dafoulas 2006, p. 2
22. ^ Olofson, Carl W. (October 2009), "A Platform for Enterprise Data Services", IDC, retrieved 7 August 2012
23. ^ a b Ward & Dafoulas 2006, p. 3
24. ^ Pardede 2009, p. 2
25. ^ a b Pardede 2009, p. 4
26. ^ Kedar 2009, pp. 1?9
27. ^ van der Aalst 2011, p. 2
28. ^ Dych? 2000, pp. 4?6
29. ^ Weik 2000, p. 361
30. ^ a b Pardede 2009, p. xiii.
31. ^ Lewis 2003, pp. 228?231.
32. ^ Han, Kamber & Pei 2011, p. 5
33. ^ Han, Kamber & Pei 2011, p. 8
34. ^ Han, Kamber & Pei 2011, p. xxiii
35. ^ "Gartner Says Worldwide IT Spending On Pace to Surpass $3.6 Trillion in 2012". Retrieved July 17, 2012.
36. ^ Bynum 2008, p. 9.
37. ^ Reynolds 2009, pp. 20?21.

Bibliography

- Alavudeen, A.; Venkateshwaran, N. (2010), Computer Integrated Manufacturing, PHI Learning, ISBN 978-81-203-3345-1
- Bynum, Terrell Ward (2008), "Norbert Wiener and the Rise of Information Ethics", in van den Hoven, Jeroen; Weckert, John, Information Technology and Moral Philosophy, Cambridge University Press, ISBN 978-0-521-85549-5
- Chaudhuri, P. Pal (2004), Computer Organization and Design, PHI Learning, ISBN 978-81-203-1254-8
- Childress, David Hatcher (2000), Technology of the Gods: The Incredible Sciences of the Ancients, Adventures Unlimited Press, ISBN 978-0-932813-73-2
- Dych?, Jill (2000), Turning Data Into Information With Data Warehousing, Addison Wesley, ISBN 978-0-201-65780-7
- Han, Jiawei; Kamber, Micheline; Pei, Jian (2011), Data Minining: Concepts and Techniques (3rd ed.), Morgan Kaufman, ISBN 978-0-12-381479-1
- Kedar, Seema (2009), Database Management Systems, Technical Publications, ISBN 978-81-8431-584-4
- Lavington, Simon (1980), Early British Computers, Digital Press, ISBN 978-0-7190-0810-8
- Lavington, Simon (1998), A History of Manchester Computers (2 ed.), The British Computer Society, ISBN 978-1-902505-01-5
- Lewis, Bryn (2003), "Extraction of XML from Relational Databases", in Chaudhri, Akmal B.; Djeraba, Chabane; Unland, Rainer et al., XML-Based Data Management and Multimedia Engineering?? EDBT 2002 Workshops, Springer, ISBN 978-3540001300 `|displayeditors=` suggested (help)
- Pardede, Eric (2009), Open and Novel Issues in XML Database Applications, Information Science Reference, ISBN 978-1-60566-308-1
- Proctor, K. Scott (2011), Optimizing and Assessing Information Technology: Improving Business Project Execution, John Wiley Sons, ISBN 978-1-118-10263-3
- Reynolds, George (2009), Ethics in Information Technology, Cengage Learning, ISBN 978-0-538-74622-9
- van der Aalst, Wil M. P. (2011), Process Mining: Discovery, Conformance and Enhancement of Business Processes, Springer, ISBN 978-3-642-19344-6
- Wang, Shan X.; Taratorin, Aleksandr Markovich (1999), Magnetic Information Storage Technology, Academic Press, ISBN 978-0-12-734570-3
- Ward, Patricia; Dafoulas, George S. (2006), Database Management Systems, Cengage Learning EMEA, ISBN 978-1-84480-452-8
- Weik, Martin (2000), Computer Science and Communications Dictionary 2, Springer, ISBN 978-0-7923-8425-0
- Wright, Michael T. (2012), "The Front Dial of the Antikythera Mechanism", in Koetsier, Teun; Ceccarelli, Marco, Explorations in the History of Machines and Mechanisms: Proceedings of HMM2012, Springer, pp. 279?292, ISBN 978-94-007-4131-7

## Further reading[edit]

- Allen, T., and M. S. Morton, eds. 1994. Information Technology and the Corporation of the 1990s. New York: Oxford University Press.
- Shelly, Gary, Cashman, Thomas, Vermaat, Misty, and Walker, Tim. (1999). Discovering Computers 2000: Concepts for a Connected World. Cambridge, Massachusetts: Course Technology.
- Webster, Frank, and Robins, Kevin. (1986). Information Technology?A Luddite Analysis. Norwood, NJ: Ablex.

## External links[edit]

- The Global Information Technology Report 2008?2009

Major information technology companies
Largest IT companies Largest Internet companies Largest software companies Semiconductor sales leaders by year
Consulting and outsourcing | Accenture Atos Booz Allen Hamilton BT CACI Capgemini CGI Group Cognizant CSC Deloitte Dell Services Digital China Fujitsu HCL Technologies Hitachi Consulting HP IBM Indra Infosys NEC NTT Data Orange Business Services TCS T-Systems Unisys Wipro
Imaging | Canon HP Kodak Konica Minolta Kyocera Lexmark Nikon Olympus Ricoh Samsung Seiko Epson Sharp Sony Toshiba Xerox
Information storage | Dell EMC Fujitsu Hitachi Data Systems HP IBM NetApp Oracle Samsung Seagate Western Digital
Internet | 360buy Alibaba Amazon.com Baidu eBay Facebook Google Groupon IAC Microsoft NHN NetEase Rakuten Salesforce.com Tencent Yahoo!
Mainframes | Fujitsu IBM
Mobile devices | Acer Apple Asus BlackBerry HTC Huawei LG Motorola Mobility Nokia Samsung Sony TCL (Alcatel) ZTE
Networking equipment | Alcatel-Lucent Avaya Cisco Ericsson Fujitsu HP Huawei Juniper Mitsubishi Electric Motorola Solutions NEC Nokia Solutions and Networks Samsung ZTE
OEMs | Celestica Compal Electronics Flextronics Foxconn Jabil Pegatron Quanta Sanmina-SCI TPV Technology Wistron
Personal computers and servers | Acer Apple Asus Dell Fujitsu HP Lenovo LG NEC Samsung Sony Toshiba
Servers only | Cisco IBM Oracle
Point of sale | NCR Toshiba
Semiconductors | Advanced Micro Devices Broadcom Freescale Semiconductor Fujitsu LG Infineon Technologies Intel Marvell Technology Group MediaTek Micron Technology Nvidia NXP Panasonic Qualcomm Renesas Electronics Samsung SK Hynix Sony STMicroelectronics Texas Instruments Toshiba
Foundries | GlobalFoundries TSMC UMC
Software | Adobe Apple CA Google HP IBM Intuit Microsoft Oracle SAP Symantec VMware
Telecommunications services | América Móvil AT&T Bell Canada BT Bharti Airtel CenturyLink China Mobile China Telecom China Unicom Comcast Deutsche Telekom Hutchison KDDI KPN KT MTN MTS NTT NTT DoCoMo Oi Orange PT Rogers Saudi Telecom SingTel SK Telecom SoftBank Mobile Sprint Corporation Swisscom Telenor Telecom Italia Telefónica TeliaSonera Verizon VimpelCom Vivendi Vodafone
Methodology: FY2012/13 applicable revenues of over: group 1-3, 6-12 - US$3 billion; group 4 - US$2 billion; group 5 - US$1 billion; group 13 - US$10 billion

Technology
Outline of technology Outline of applied science
Fields |
Agriculture | Agricultural engineering Aquaculture Fisheries science Food chemistry Food engineering Food microbiology Food technology GURT ICT in agriculture Nutrition
Biomedical | Bioinformatics Biological engineering Biomechatronics Biomedical engineering Biotechnology Cheminformatics Genetic engineering Healthcare science Medical research Medical technology Nanomedicine Neuroscience Neurotechnology Pharmacology Reproductive technology Tissue engineering
Buildings and Construction | Acoustical engineering Architectural engineering Building services engineering Civil engineering Construction engineering Domestic technology Facade engineering Fire protection engineering Safety engineering Sanitary engineering Structural engineering
Educational | Educational software Digital technologies in education ICT in education Impact Multimedia learning Virtual campus Virtual education
Energy | Nuclear engineering Nuclear technology Petroleum engineering Soft energy technology
Environmental | Clean technology Clean coal technology Ecological design Ecological engineering Ecotechnology Environmental engineering Environmental engineering science Green building Green nanotechnology Landscape engineering Renewable energy Sustainable design Sustainable engineering
Industrial | Automation Business informatics Engineering management Enterprise engineering Financial engineering Industrial biotechnology Industrial engineering Metallurgy Mining engineering Productivity improving technologies Research and development
IT and communications | Artificial intelligence Broadcast engineering Computer engineering Computer science Information technology Music technology Ontology engineering RF engineering Software engineering Telecommunications engineering Visual technology Web engineering
Military | Army engineering maintenance Electronic warfare Military communications Military engineering Stealth technology
Transport | Aerospace engineering Automotive engineering Naval architecture Space technology Traffic engineering Transport engineering
Other applied sciences | Cryogenics Electro-optics Electronics Engineering geology Engineering physics Hydraulics Materials science Microfabrication Nanoengineering
Other engineering fields | Audio Biochemical Ceramic Chemical Polymer Control Electrical Electronic Entertainment Geotechnical Hydraulic Mechanical Mechatronics Optical Protein Quantum Robotics Animatronics Systems
Components | Infrastructure Invention Timeline Knowledge Machine Skill Craft Tool Gadget
Scale | Femtotechnology Picotechnology Nanotechnology Microtechnology Macro-engineering Megascale engineering
History | Prehistoric technology Neolithic Revolution Ancient technology Medieval technology Renaissance technology Industrial Revolution Second Jet Age Digital Revolution Information Age
Theories and concepts | Appropriate technology Critique of technology Diffusion of innovations Disruptive innovation Dual-use technology Ephemeralization Ethics of technology High tech Hype cycle Inevitability thesis Low-technology Mature technology Philosophy of technology Strategy of Technology Technicism Techno-progressivism Technocapitalism Technocentrism Technocracy Technocriticism Technoetic Technoethics Technological change Technological convergence Technological determinism Technological escalation Technological evolution Technological fix Technological innovation system Technological momentum Technological nationalism Technological rationality Technological revival Technological singularity Technological somnambulism Technological utopianism Technology lifecycle Technology acceptance model Technology adoption lifecycle Technomancy Technorealism Transhumanism
Other | Emerging technologies List Fictional technology Technopaganism High-technology business districts Kardashev scale List of technologies Science, technology and society Technology dynamics Science and technology by country Technology alignment Technology assessment Technology brokering Technology companies Technology demonstration Technology education Technical universities and colleges Technology evangelist Technology fusion Technology governance Technology integration Technology journalism Technology management Technology policy Technology shock Technology strategy Technology and society Technology transfer Technoself Technosignature Weapon List
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