History of computer technology
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evices have been used to aid computation for
thousands of years, probably initially in the form of a tally stick.* The Antakya,
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* 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 Zeus 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.* The first recognizably modern
electronic digital stored-program computer 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 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 transistorized computer, developed at the University of
Manchester and operational by November 1953, consumed only 150 watts in its
final version.*
Data storage
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arly 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.*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.* 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
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* and used in the Ferranti Mark 1,
the world's first commercially available general-purpose electronic computer.*
IBM introduced the first hard disk drive in 1956, as a component of their 305 RAMAC computer system.*
Most digital data today is still stored magnetically on hard disks, or
optically on media such as CD-ROMs.[21] 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:* 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 Exabyte’s in
1986 to 295 Exabyte’s in 2007,* doubling roughly every 3 years.
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atabase management systems
emerged in the 1960* 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),*which
is still widely deployed more than 40 years later.*IMS stores data hierarchically,* but in the 1970s Ted Coded 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*
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.*
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".*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.*
Data retrieval
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he 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.*Most
of the world's digital data is unstructured, and stored in a variety of
different physical formats* 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).*
Data transmission
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ata transmission has
three aspects: transmission, propagation, and reception.* It can be broadly categorized as broadcasting, in which information is transmitted unidirectional
downstream, or telecommunications, with
bidirectional upstream and downstream channels.*
XML has been increasingly employed as a
means of data interchange since the early 2000s,* particularly for machine-oriented
interactions such as those involved in web-oriented protocols such as SOAP,*describing
"data-in-transit rather than ... data-at-rest".*One
of the challenges of such usage is converting data from relational databases into
XML Document Object Model (DOM) structures.*
Data manipulation
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ilbert
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.*
Massive amounts of data are stored
worldwide every day, but unless it can be analyzed and presented effectively it
essentially resides in what have been called data tombs: "data archives
that are seldom visited".*To address that issue, the field of data mining – "the process of discovering
interesting patterns and knowledge from large amounts of data"*–
emerged in the late 1980s.*
Perspective
Academic perspective
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n 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
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n 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 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.
ICT in Education
Information and
Communication Technology (ICT) can contribute to universal access to education,
equity in education, the delivery of quality learning and teaching, teachers’
professional development and more efficient education management, governance
and administration.
UNESCO takes a holistic and comprehensive approach to promoting
ICT in education. Access, inclusion and quality are among the main challenges
they can address. The Organization’s Intersect oral Platform for ICT in
education focuses on these issues through the joint work of three of its
sectors: Communication & Information, Education and Science.
UNESCO’s global network of offices, institutes and
partners provide Member States with resources for elaborating ICT in education
policies, strategies and activities. In particular, the UNESCO Institute for
Information Technologies in Education (IITE), based in Moscow, specializes in
information exchange, research and training on the integration of ICT in
education while UNESCO’s Bangkok office is strongly involved in ICT for
Education in Asia and the Pacific.
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