A computer network can be simple and limited to a small number of computers or complex, linking a large number of computers.

A computer that is not connected to a network is referred to as a stand-alone computer. When a computer is physically connected to a local area network, using a cable or other communications channel, the computer becomes a workstation on the network. Each device on the network including workstations, servers, and printers is referred to as a node.

Node: A processing location on a network.

A workstation normally has all of the usual resources found in the personal computing environment (hard drive, software, data and printer). However, users of workstations will also have access to network resources, which typically include application software, storage space for data files, and printers other than those on the local workstation. On a network, the network server typically provides the applications software and storage space for data files.

Network server: A computer that is connected to the network and that ‘serves’ or distributes resources to network users.

Networks use different kinds of servers to carry out specialised functions. For example, a file server is a computer and storage device dedicated to storing files.

File server: A computer that serves or distributes application programs and data files to workstations within a computer network. The hard drive of the file server is shared by the workstations on the network.

Any user on the network can store files on the server. Other types of servers include a print server to manage one or more printers and a database server to process database queries.

Most network users will need to understand file servers because this is where they will store their files on the network. A typical local area network uses a powerful PC as a file server. However, a minicomputer or mainframe computer can also be a file server. File servers fall into three categories; dedicated, non-dedicated and application servers.

A dedicated file server is devoted only to the task of delivering programs and data files to workstations. A dedicated file server does not process data or run programs for the workstations. Instead, programs run using the memory and processor of the workstation.

In some cases, a network computer performs a dual role as both file server and workstation. When a non-dedicated file server is used, the computer workstation functions like a normal workstation, but other workstations can access programs and data files from the hard disk of the user’s computer workstation.

An application server is a computer that runs applications software and runs the results of processing to workstations as requested. An application server makes it possible to use the processing power of both the server and the workstation. Use of an application server splits processing between the workstation client and the network server. The method is also referred to as client/server architecture.

Some networks include a host computer, usually a minicomputer or mainframe attached with terminals. A terminal has a keyboard and screen but does not have a local storage device and does no processing on its own. When a terminal is connected to a host computer, all processing takes place on the host.

The software on a local area network typically includes many of the same applications one might use in a personal computing environment, such as word processing, spreadsheet, database management and so on. As the use of networks increase, however, organisations have begun to demand software that facilitate the flow and sharing of documents. This software includes groupware and workflow software.

Groupware: Applications software that supports collaborative work between a group of users by managing schedules, sharing documents and undertaking intragroup communications.

Essentially, groupware manages a pool of documents and allows users to access those documents simultaneously. A key feature of groupware is document version management which maintains all revisions within a document when more than one group member revises a document.

Workflow software: Software that automates the process of electronically routing documents from one person to another in a specified sequence and time.

Workflow software facilitates a process or a series of steps. Workflow is based on a ‘process-centred model’ as opposed to groupware’s ‘information-centred model’. With workflow software, the focus is on a series of steps. With groupware software, the documents are the focus.

Peer-to-peer network: workstation has responsibilities.

Peer-to-peer networks simply link a number of PCs together with no network server. This is a cheaper way of networking, and while files and printers can be shared the wider advantages of having a network server are lost.

The main advantage of a computer network is that all the users can share resources, rather than have users each maintain his or her own resources. It is not necessary to purchase multiple copies of software; instead a licence can be purchased to use the software within the network which allows everyone to use the program at the same time.

When a computer network is used, finding, retrieving, and storing files on a network is not very different from the process used on a stand-alone computer. However, when using a network, security is much more of an issue. Information is now accessible to a wide group of people, and sensitive or personal information needs to be protected.

An internal network that belongs to an organisation and is accessible only by that organisation’s members is often referred to as an Intranet.

Intranet: An internal computer network that belongs to an organisation and is accessible only by that organisation’s members.