networking

Why Network?
Networks have been used for a long time in large businesses, colleges and other organisations because of the need to share files, applications software and printers, and to provide a centralised backup facility and for internal
communication and e-mail.
Apart from sharing files, CDs and applications software you can also
communicate with people in different parts of your business premises. Installing a network is relatively simple - it's basically a case of installing
network interface cards in the computers, connecting them thru a hub and
installing networking software.
The network operating system consists of a family of programs that run in the networked computers and are actually a combination of programs that give some computers and peripherals the ability to accept requests for service across the network and give other computers the ability to correctly use those services. Computers that share their resources are called servers. They share their hard-disk drives, attached peripherals such as printers, digital copiers and communications circuits. Servers inspect requests for proper authorization, check for conflicts, and then provide the requested service.

Networked Peripherals

In 1991, a new category of products called networked peripherals became generally available. Initially, these included printers and modems but now also digital copiers with their own network connections. Network peripherals have internal specialized processors to run networking server software, so they don't have to be directly attached to a computer. Application programs running on client PCs can use a networked printer or modem as if it were locally attached.

File servers store files created by application programs. In some
configurations, the file servers might also hold the application programs themselves. A file server is a computer that has a hard-disk drive large enough to share. File servers provide the ability to simultaneously access the same file. People who update databases - customer service representatives taking phone orders, for example, need to use the same inventory and financial data files at the same time. File-server software allows shared
access to specific segments of the data files under controlled conditions.

Print servers accept print jobs sent by anyone across the network. Since even the fastest print jobs typically still take 5 to 10 seconds per page, spooling the print jobs (saving them in a disk file until the printer is ready to accept them) is a critical function of the print-server software. The print-server software also
reports the status of jobs waiting for printing and recognizes the priorities
assigned to specific users. Computers can run both the file-server and print-server software, or print-server software can run in specialized processors
inside networked digital copiers or in small self-contained print-server devices.

Other programs that give the ability to use those shared resources are called clients. It is common to have client and server software running in the same computer, so you can use the resources on other computers while your fellow workers make use of your disk space, printers, or
communications devices. Client software works with the internal operating system of a computer so it can route requests from application programs and from the keyboard out to file servers and print servers on the network. Network communications software packages the requests from the client computers and sends the requests across the network. This software
conforms to specific protocols for addressing, ensuring delivery and
ensuring accuracy. Typical suites of network communications protocols include Apple's Apple File Protocol (AFP), Microsoft's NetBIOS Extended User Interface (NETBEUI), and Novell's Sequential Packet Exchange and
Internetwork Packet Exchange (SPX and IPX).