Computer software
These are the programmes which are installed onto a computer to enable it to perform a specific task, as opposed to the physical components of the computer system (hardware). Firstly an operating system needs to be installed which controls the overall activity of the computer (eg Windows XP, Windows Vista, Apple Mac OS X) by interfacing with the computer hardware and other software. On top of this, application software is added to perform specific functions such as word processing, spreadsheets or accountancy packages. Multiple applications bundled together as a package are sometimes referred to as an application suite. Microsoft Office is a typical example as it combines a word processor, spreadsheet, personal information & e-mail manager and other discrete applications in one package. Often the separate applications in a suite may have some capability to interact with each other making it more user friendly for the operator. For example, a spreadsheet may be able to be embedded into a word processor document, even though it had been created in the separate spreadsheet application. There are various specialised computer software programmes which can be purchased to perform a specific function, eg computer-aided design (CAD) software which could be used by architects, engineers and graphic designers to assist in precision drawing.
To protect your computer from malicious software it is vital to have antivirus software installed on your computer. Antivirus software are computer programmes that attempt to identify and neutralise or eliminate computer viruses and other threats such as worms, phishing attacks and trojan horses. Typically this is achieved by scanning files to look for known viruses and identifying suspicious behaviour from any computer program which may indicate an infection. A firewall is a dedicated software appliance which inspects network traffic passing through it, and denies or permits passage based on a set of rules. The basic task of a firewall is to regulate some of the flow of traffic between computer networks of different trust levels. For example the Internet, which is a zone with no trust, and an internal network, which is a zone of higher trust. It is important to keep your software up to date by performing regular upgrades. This replaces a product with a newer or better version of the same product in order to bring the system up to date or to improve its characteristics.