Information technology (IT):
It is the
application of computer and telecommunications equipment to store, retrieve, transmit
and manipulate data, often in the context of a business or other enterprise.
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 industries
are associated with information technology, including computer hardware,
software, electronics, semiconductors, internet, telecom equipment,
engineering, healthcare, e-commerce and computer services.
Data storage:
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. 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.
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), which is still widely deployed more
than 40 years later. IMS stores data hierarchically, 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.
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:
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. 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:
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 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,[28] describing "data-in-transit rather than ...
data-at-rest".[33] One of the challenges of such usage is converting data
from relational databases into XML Document Object Model (DOM) structures.
Data manipulation:
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". 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.
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