Data: How it began

Mail, Telephone, TV, radio, books, newspapers, magazines and these are the main ways we can send and receive data, and have not changed significantly in a generation. However, communication systems, computer systems, which transmit data on the lines of communication such as telephone lines and cables have been gradually developed since the mid-1960s. Let us look at how it came about.
In the early days of computing, centralized processing of data contained everything - all the processing hardware and software - in one central location. Computer manufacturers responded to this trend by building even larger, general-purpose computers, so that all departments in an organization can be serviced. In the end, however, proved to be a total centralization uncomfortable. All input data had to be physically transported to the computer and all processed material was to be received and delivered to the user.Stressing the centralized data processing was like insisting that all conversations between people are face-to-face in one designated room.
The next logical step was to teleprocessing systems-terminals connected to a central computer via communication lines.Teleprocessing systems allowed users to remotely access a central computer from their terminals in other buildings, and even other cities. However, despite the fact that access to the computer system was decentralized, all processing is still centralized, it is performed by a single company's central computer.
In 1970, companies began to use the mean, often away from the central computer. Were clearly decentralized systems because the smaller computers could do some processing on their own, but some also have access to a central computer. This new configuration has been determined distributed data processing (DDP). It is similar to teleprocessing, except that the place is not only remote access, but also remote processing. A typical use of distributed data processing system is a company or organization with multiple locations, perhaps subsidiaries or retail outlets.
The whole picture of distributed computing has changed dramatically with the emergence of networks of personal computers. The network we mean a computer system that uses communications equipment to connect two or more computers and their resources. DDP systems are networks. But especially important in today's business world are in local area networks (LAN), which are designed to share data and resources between a number of individual computer users in an office or building. We will examine the network in more detail later in this chapter.
In the next chapter we will view elements of the communications system to give an overview of how these elements work together.