Information technology (IT)
is
the use of computers to store, retrieve, transmit, and manipulate
data,[1] or information, often in the context of a business or other
enterprise.[2] IT is considered to be a subset of information and
communications technology (ICT).
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 Harold J. Leavitt and Thomas L. Whisler commented that
"the new technology does not yet have a single established name. We
shall call it information technology (IT)." Their definition consists of
three categories: techniques for processing, the application of
statistical and mathematical methods to decision-making, and the
simulation of higher-order thinking through computer programs.[4]
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. Several products or
services within an economy are associated with information technology,
including computer hardware, software, electronics, semiconductors,
internet, telecom equipment, and e-commerce.[5][a]
Based on the storage and processing technologies 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 (1940–present).[3] This
article focuses on the most recent period (electronic), which began in
about 1940.
History of computer technology:
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, and the earliest known geared mechanism.[8] Comparable geared devices did not emerge in Europe until the 16th century, and it was not until 1645 that the first mechanical calculator capable of performing the four basic
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. Although it was programmable,
it was not general-purpose, being designed to perform only a single
task. It also lacked the ability to store its program in memory;
programming was carried out using plugs and switches to alter the
internal wiring.[10] 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.[11]
The development of transistors in the late 1940s at Bell Laboratories
allowed a new generation of computers to be designed with greatly
reduced power consumption. The first commercially available
stored-program computer, the Ferranti Mark I,
contained 4050 valves and had a power consumption of 25 kilowatts. By
comparison the first transistorised computer, developed at the
University of Manchester and operational by November 1953, consumed only
150 watts in its final version.[12]
Electronic data processing
Data storage
Punched tapes were used in early computers to represent data.
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, which is used in modern computers, dates from World War II, 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]
IBM introduced the first hard disk drive in 1956, as a component of their 305 RAMAC computer system.[18]:6 Most digital data today is still stored magnetically on hard disks, or optically on media such as CD-ROMs.[19]:4–5 Until 2002 most information was stored on analog devices,
but that year digital storage capacity exceeded analog for the first
time. As of 2007 almost 94% of the data stored worldwide was held
digitally:[20]
52% on hard disks, 28% on optical devices and 11% on digital magnetic
tape. 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,[21] doubling roughly every 3 years.[22]
Databases
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),[23] which is still widely deployed more than 50 years later.[24] IMS stores data hierarchically,[23] 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.[25]
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.[citation needed]
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.[23]
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".[26] 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.[27]
Data retrieval
The relational database model introduced a programming-language independent Structured Query Language (SQL), based on relational algebra.
The terms "data" and "information" are not synonymous. Anything
stored is data, but it only becomes information when it is organized and
presented meaningfully.[28]:1–9 Most of the world's digital data is unstructured, and stored in a variety of different physical formats[29][b] even within a single organization. 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, organized in such a way as to
facilitate decision support systems (DSS).[30]:4–6
Data transmission
Data transmission has three aspects: transmission, propagation, and reception.[31] It can be broadly categorized as broadcasting, in which information is transmitted unidirectionally downstream, or telecommunications, with bidirectional upstream and downstream channels.[21]
XML has been increasingly employed as a means of data interchange since the early 2000s,[32] particularly for machine-oriented interactions such as those involved in web-oriented protocols such as SOAP,[27] describing "data-in-transit rather than ... data-at-rest".[32] One of the challenges of such usage is converting data from relational databases into XML Document Object Model (DOM) structures.[33]:228–31
Data manipulation
Hilbert and Lopez 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.[21]
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".[34] To address that issue, the field of data mining – "the process of discovering interesting patterns and knowledge from large amounts of data"[35] – emerged in the late 1980s.
Perspectives
Academic perspective
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."
Commercial and employment perspective
Companies in the information technology field are often discussed as a group as the "tech sector" or the "tech industry"
In a business context, the Information Technology Association of America
has defined information technology as "the study, design, development,
application, implementation, support or management of computer-based information systems".[42][page needed]
The responsibilities of those working in the field include network
administration, software development and installation, and the planning
and management of an organization's technology life cycle, by which
hardware and software are maintained, upgraded and replaced.
The business value of information technology lies in the automation
of business processes, provision of information for decision making,
connecting businesses with their customers, and the provision of
productivity tools to increase efficiency.
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