Computers are used for many reasons and in many different places. They may be of different sizes and processing power, but all computers have some features in common. In order for most computers to perform useful functions, there are three things that have to work together:
- Hardware – the physical components, both internal and external, that make up a computer.
- Operating System – a set of computer programs that manages the hardware of a computer. An operating system controls the resources on a computer, including memory and disk storage. An example of an operating system is Windows XP.
- Application Software – programs loaded on the computer to perform a specific function using the capabilities of the computer. An example of application software is a word processor or a computer game.
Local and Network Applications
• The computer is only as useful as the program or application on it. Applications can be divided into two general categories:
• Business/Industry Software – Software designed for use by a specific industry or market. Examples include: medical practice management tools, educational tools and legal software.
• General Use Software – Software used by a wide range of organizations and home users for various purposes. These applications can be used by any business or individual.
• General use software includes integrated applications packages known as Office Suites. They usually include applications such as word processing, spreadsheet, database, presentation and email/contacts/schedule management.
• Other popular applications include graphics editing software and multimedia authoring applications. These tools allow users to manipulate photos as well as create rich media presentations that use voice, video and graphics.
• In addition to Business/Industry and General Use software, an application can be classified as local or networked.
• Local application – A local application is a program, such as a word processor, that is stored on the hard disk of the computer. The application runs only on that computer.
• Network application – A network application is one that is designed to run over a network, such as the Internet. A network application has two components, one that runs on the local computer and one that runs on a remote computer. Email is an example of a network application.
• Most computers have a combination of local and network applications installed.
Classes of Computers
• There are many different types of computers available including:
 Mainframes
 Servers
 Desktops
 Workstations
 Laptops
 Hand-held portable devices
- Each type of computer has been designed with a particular purpose in mind, such as portable access to information, processing of detailed graphics, and so on.
- The most common types of computers used in homes and businesses are servers, workstations, desktops, laptops and other portable devices. Mainframes, on the other hand, are large centralised computers found in sizeable enterprises and purchased through specialised resellers.Â
