Information technology ( IT ) is the application of computers to store, study, retrieve, transmit, and manipulate data ,  or information , often in the context of a business or other enterprise.  IT is considered a subset of information and communications technology (ICT). In 2012, Zuppo proposed an ICT hierarchy where each hierarchy level “contain [s] some degree of commonality in that they are related to technologies that facilitate the transfer of information and various types of electronically mediated communications.” 
The term is Commonly used as a synonym for computers and computer networks, goal aussi it encompasses other information distribution technologies Such As television and telephones. Several industries are associated with information technology, including computer hardware , software , electronics , semiconductors , internet , telecom equipment , and e-commerce .  [a]
Humans have been storing, retrieving, manipulating, and communicating information since the Sumerians in Mesopotamia developed writing in about 3000 BC,  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 require a single established name. 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.
Based on the storage and processing technologies employed, it is feasible to Distinguish separate furnace stages of IT development: pre-mechanical (3000 BC – 1450 AD), mechanical (1450-1840), electromechanical (1840-1940) and electronic (1940 -Present).  This article focuses on the most recent period (electronic), which began in about 1940.
History of computer technology
Devices have been used to help computers for years, probably initially in the form of a tally stick .  The Antikythera mechanism , dating from the beginning of the first century BC, is known to the earliest known mechanical analog computer , and the earliest known geared mechanism.  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 arithmetical operations was developed. 
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 has the ability to store its program in memory; Programming was carried out using plugins and switches to alter the internal wiring.  The first recognizable modern electronic digital stored-program was the Manchester Small-Scale Experimental Machine (SSEM), which ran its first program on 21 June 1948. 
The development of transistors in the late 1940s at Bell Laboratories, 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 operating by November 1953, consumed only 150 watts in its final version. 
Electronic data processing
Early electronic computers such as Colossus made use of punched tape , a long strip of paper on which was represented by a series of holes, a technology now obsolete. Electronic data storage, which is used in modern computers, dates from World War II, when a form of delayed memory was shifted to remove the clutter from radar signals, the first practical application of which was the mercury delay line.  The first random-access digital storage device was the Williams tube , based on a standard cathode ray tube ,  but the information stored in it and the delay line 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  and used in the Ferranti Mark 1 , the world’s first commercially available general-purpose electronic computer. 
IBM introduced the first disk drive in 1956, as a component of their 305 RAMAC computer system.  Most digital data today is still stored on CD-ROMs .  Until 2002 most information was stored on analog devices , but that year digital storage capacity for the first time. As of 2007 almost 94% of the data stored worldwide was held digitally:  52% on hard disks, 28% on optical devices and 11% on digital magnetic tape. It existed in 1986 to exalted in exabytes in 2007,  doubling roughly every 3 years. 
Database management systems emerged in the 1960s  to address the problem of storing and retrieving large quantities of data accurately and quickly. One of the Earliest Such systems Was IBM ‘s Information Management System (IMS),  qui est still Widely Deployed more than 50 years later.  IMS stores data hierarchically ,  but in the 1970s Ted Codd proposed an alternative relational storage model based on set theory and predicate logicand the familiar concepts of tables, rows and columns.
All database management systems consist of a number of components that allow the data to be accessed simultaneously by many users while maintaining its integrity. [ Citation needed ] A characteristic of all databases is que la structure of the data is defined They Contain and Stored separately from the data Itself, in a database schema . 
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 both theoretical and practical effort”.  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. 
The relational database model Introduced a programming-language independent Structured Query Language (SQL), is based 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.  Most of the world’s digital data is unstructured, and Stored in a variety of different physical formats  [b] Even Within a single organism. Data warehouses began to be developed in the 1980s to integrate these disparate stores. Typically They Contain data Extracted from various sources, Including external sources Such As the Internet Organized in Such a way as to Facilitate decision supporting systems (DSS). 
Data transmission has three aspects: transmission, propagation, and reception.  It can be broadly categorized as broadcasting , in which information is transmitted unidirectionally downstream, or telecommunications , with bidirectional upstream and downstream channels. 
XML has been increasingly used as a data interchange since the early 2000s,  particularly for machine-oriented interactions as web-oriented protocols such as SOAP ,  describing “data-in-transit … data-at-rest “.  One of the challenges of such use is the XML Document Object Model (DOM) structures. 
Hilbert and Lopez, “The Application of the Moore’s Law “. 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. 
Massive amounts of data are stored worldwide every day, but it can not be analyzed and reported. [ 37] – emerged in the late 1980s.  To address this issue, the field of data mining – the process of discovering interesting patterns and knowledge from large amounts of data . 
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. Computer software, hardware and software products for the organization of computer hardware and software. 
Commercial and employment perspective
Companies in the information technology field are often referred to as “tech sector” or “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 “.  The role of the organization in the management of the organization and management of the organization and its management.
The business value of information technology 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.
|Category||2014 spending||2015 spending|
|Data center systems||140||144|
Employment in the Computer Systems and Design Related Services, 1990-2011 
Occupational growth and wages in computer systems design and related services, 2010-2020 
Projected percent change in employment in selected occupations in computer systems design and related services, 2010-2020 
Projected average annual percent change in output and employment in selected industries, 2010-2020 
The field of information ethics was established by mathematician Norbert Wiener in the 1940s.  Some of the ethical issues associated with the use of information technology include: 
- Breaches of copyright by the copyright holders
- Employers monitoring their employees’ emails and other Internet use
- Unsolicited emails
- Hackers accessing online databases
- Web sites installing cookies or spyware to monitor
- Data processing
- Health information technology
- Information management
- Information and communications technology (ICT)
- Journal of Cases on Information Technology
- Knowledge society
- List of the largest information technology companies
- Outline of information technology
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