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Computer Network
Computer Network is a group of computers and other devices connected by a communications link that enables any computer to interact with any other computers on the network. Computer Networks commonly include microcomputers and shared resources such as laser printers and large hard disks. The devices on a LAN are known as nodes, and the nodes are connected by cables through which messages are transmitted. Communication media can be a copper wire, fiber optics, microwaves and communication satellite.
1.2 Why do we require Computer Networks?
1. Sharing Information: Just a lot of information is moved about a business; some information is centrally controlled and shared. Most businesses have one set of financial books, and not everyone is given access to them. The information must be kept consistent and secure, and timely access must be given to those who need the information to run the business.
2. Sharing Hardware Resources: Computers that are not networked cannot effectively share resources. For instance a small office with 10 stand-alone computers and one printer allows only the user with printer attached to his or her computer to print. Others user must put their data on a floppy disk, transfer it to the computer with the printer, and print it from there. This of course interrupts the user who would normally be using the computer with the printer attached. A network allows anyone connected to the network to use the printer, not just the individual sitting at the computer to which the printer is attached. Networked computers can also share FAX modems, Scanners, Hard-Disks, CD-ROMs, Tape Backup Unit, Plotters etc.
3. Preserving Information: A network also allows for information to be backed up to a central location. Important information can be lost by mistake or by accident when a stand-alone computer has no backup. It is difficult to maintain regular backups on a number of standalone computers. When you backup to a central location (often to a tape cartridge in the network server), you have one place to look for the lost information and you can be assured that the information is being backed up.
4. Protecting Information: A network provides a more secure environment for a company's important information. With stand-alone computers, access to the computers often means access to the information on the computers. Networks provide an additional layer of security by way of passwords. You can give each network user a different password, allowing the network server to distinguish among those who need access to have it and protecting the information from tempering by those who do not.
5. E-Mail: The computer network can also help people communicate. One of the greatest benefits to users of networks is electronic mail or e-mail. Rather then exchanging memos and directives on paper, engaging printing costs and delays, network user can instantly send messages to others and even check to see whether their in messages has been received.
