CHAPTER 4: DATA COMMUNICATION AND
NETWORK
Why are networks useful?
A network is a group of computers which are connected together. It could be a group of just two computers, or it could be thousands. Computers in a network are also connected to printers, and other devices such as routers and hubs. Because of these connections, many users can share important data and programs. They can also share the same printer and internet connection.
When did LANs (Local Area Networks) start?
Before PCs became widely used in the 1980s, most workplaces would have one just one main computer which stored all the data and did all the processing. Employees had to access the main computer from “dumb terminals” at their desks. Nowadays, most workplaces have LANs: universities, factories, banks, etc. A LAN covers a small area, such as a home, office or a group of buildings. A LAN consists of PCs, printers, routers, and other devices. PCs can run