1.1.2 Types of Computer

What is a mainframe computer?

• Mainframe computers are the big, powerful, expensive computers used in the background by most large organisations. The power of the mainframe can be distributed amongst many people accessing the mainframe via their own PC. Organisations such as large insurance companies would use the mainframe to keep track of their policyholders and send out renewal notices.

What is a PC?

• IBM invented the PC (Personal Computer) way back in 1981. All PCs released since then are in many ways compatible with the original design, though many extensions have been made. The term PC compatible relates to PCs manufactured by companies other than IBM which are compatible with the traditional PC specification. In the early days, most PCs ran an operating system called DOS (Disk Operating System). These days most PCs will be running a version of Microsoft Windows.

What is a Mac?

• The Apple Mac is a computer, but NOT a PC. It uses a different operating system, and requires special versions of application programs (such as wordprocessors or spreadsheets). Even the hardware add-ons have to be customised to some extent to be able to be connected to a Mac. In the early days the thing which really distinguished the Mac over the PC was the GUI (Graphical User Interface), or in plain English the way you could use the mouse to drive the computer. In the early days of the PC, you really had to be a bit of an expert to use and maintain your PC. Recently the differences between the PC and the Mac have blurred, with Microsoft buying a stake in Apple.

What is a networked computer?

• A network allows you to connect two or more computers together. This allows data stored on one PC to be retrieved by other PCs connected to the network. It also allows the sharing of resources. Thus instead of each PC requiring its own printer to be directly connected to it, you can have a single printer shared amongst many networked PCs. In the early days, to network PCs together was a complicated task, only to be attempted by qualified

What are laptop & palmtop computers?


• Laptop computers, as the name implies, are small portable computers which can run on batteries as well as mains power. They use special screens, rather than the traditional bulky VDUs (Visual Display Units), which allows for longer

battery life as well as portability. A newer term, “Notebooks”, simply indicates a VERY small laptop. These are especially popular with salespersons on the move or people giving presentations. While they tend to still be more expensive than an equivalent Desktop computer, they can now match the power of a Desktop computer. Palmtops are even smaller computers which can literally fit into the palm of your hand.

What is a Personal Digital Assistant (PDA)?

• These devices use a special pen, rather than a keyboard and can be used for

storing and retrieving information. Like most computer devices, many can connect to the Internet. They are extremely compact. Types of computer - Mainframe

• Capacity: Very powerful computers often connected to many individual PCs

over a network. Speed: Much faster than PCs used for processing large amounts of data such as mail-shots, salaries, tax etc. Costs: Very, very expensive, only affordable by large companies. Typical Users: Only used by large companies including banks, building societies etc.

1.1 General Concepts

1.1.1 Hardware, Software, Information Technology

1.1.1.1 Understand the terms hardware, software, Information Technology (IT).

Hardware

• The term hardware refers to the physical components of your computer such as the system unit, mouse, keyboard, monitor etc.

Software

• The software is the collection of instructions which makes the computer work.

For instance, when you type in words via the keyboard, the software is responsible for displaying the correct letters, in the correct place on the screen. Software is held either on your computer’s hard disk, CD-ROM, DVD or on a diskette (floppy disk) and is loaded (i.e. copied) from the disk into the computers RAM (Random Access Memory), as and when required.

Information Technology (IT)

• This is a general term which relates to the use of computers as an aid to

creating and maintaining data, i.e. information. IT is related to all aspects of managing and processing information, especially within a large organisation. Computers are critical to managing information, and computer departments within large organisations are often called IT departments. Alternative phrases are IS departments (Information Services) or MIS departments (Management Information Services). People working with computers within large companies will often refer to their job, as “working in IT”.

Contents

Module 1 - Concepts of Information Technology (IT)

Module 2 - Using the Computer and Managing Files

Module 3 - Word Processing

Module 4 - Spreadsheets

Module 5 - Database

Module 6 - Presentation

Module 7 - Information and Communication