The new possibilities, which result from the connecting of computers, has
first been recognized in military and scientific institutions. But only with
the appearance of applications, that allow a simple and intuitive access to
a multitude of connected information, the network in the form of the ``World
Wide Web'' became a mass medium.
As important as the actual computers and cables is a common language, which
allows to establish connections and to exchange data, a protocol. The
protocol of the internet is called TCP/IP.
Internet: the collection of connected computers all over the world
that communicate via the TCP/IP protocol.
- An important part of the TCP/IP protocol is a number, which denotes a sender
or receiver uniquely, the IP address. For simplicity of usage these
numbers are translated into names (so called domain names), which
have the following form:
COMPUTERNAME denotes the computer itself, SUBNET is a
subdivision of NET, and DOMAIN a global division of all subnets
world wide. According to the size of a net (i.e. number of connected
computers) SUBNET can be missing or divided further.
- The address
- Special domains (or ``top level domains'') exist for many countries and (for
historical reasons) for special organizations in the USA. Often one can
infer the geographical position of a computer from its domain name.
|top level domain
||University in the USA
||companies (sometimes world wide)
- The communication via the TCP/IP protocol is usually hidden from the
user. Important are the high level applications or internet
- Some important internet services:
- private messages between persons
- bulletin boards, which can be read locally or world wide, mostly with
- transfer of files (documents, programs) between computers
- remote access to a computer
- With the growth of the internet it became difficult to find specific
informations. Scientists at the european research center CERN created a
pioneering system that allows the integration of different kinds of
documents with arbitrary links: the World Wide Web (WWW).
- Basic elements of the WWW are:
- a protocol for the transfer of very diverse data from a source computer
(the WWW server) to the computer of the user, i.e. the
Hypertext Transfer Protocol, or http),
- a language that allows to describe the content of a document, including
references to other doucuments (HTML),
- an application that displays HTML documents and allows to follow links
easily, even to documents on different servers (the browser).
Peter Junglas 8.3.2000