Information technologies and computer networks

“Technology” comes from Greek techne (craft, art) and logos (science); it means applying means and methods in an ordered way to reach a goal. The methods and means that people use to search for, collect, store, process and use information are called information technology. It has two parts: inner factors – methods (for example the order of a lesson, an algorithm) and outer factors – means (a computer, phone, book, projector). Information technologies are used in industry, banking, education, medicine, transport, communication and daily life; besides computers they include communication, television and radio. Computers are joined into a network to share files and devices. A network inside one room or building is local, one within a country is regional, and one across the world is global. In a local network the main computer is the server, and the computers joined to it that receive its services are clients. To send a computer’s digital signal over a telephone line, a modulator turns it into an analog signal and the demodulator on the receiving side turns it back into digital; a device doing both is a MODEM (MOdulator + DEModulator). Today homes mostly use optical fibre, a Wi-Fi router or a mobile network, but the idea of converting signals is still there. An information system is a system for receiving, sending and storing large volumes of information and quickly finding the needed information: it consists of computers, a network, programs, a database and people.