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Introduction to Computer Basics

You can check the previous part on introduction to computers which is a good guide for beginners.

Types of computers can be classified according to operation principles.

There Are Three Types of Computers Based on Their Principles of Operation:

  1. Analog computers: They are used to manipulate analogue data (continuous and uncountable data) for example they are good in dealing with physical variables such as pressure, voltage, temperature, speed, among others. These computers are almost obsolete nowadays.
  2. Digital Computers: They are specifically designed to work on digital data using the binary numbering system which uses two numbers, 0 and 1 (binary Zero and One). Digital computers are more accurate and faster as compared to analogue computers. They are used widely in the research, business, education, and communication sectors among others. In another simple way, it is a computer that performs logical and mathematical operations with quantities represented as digits, usually in the binary number system.
  3. Hybrid Computers: These types of computers are usually designed for specialized tasks. Their design is a combination of both analogue and digital computers' best features. The digital part is used as the controller and provides logical and numerical calculations, and on the other hand, the analogue component serves as a solver of differential equations and other complex mathematical equations.

Analog Computing Machine

Analog Computing Machine

Analog Computing Machine

Computers Classified According to Size and Power

  1. Supercomputers: They are the fastest, most powerful and most expensive computers that we have today in the computing world. They are mainly used for complex works for example in most scientific research stations, weather forecasting stations, space exploration among other places.
  2. Mainframe computers: They are large and powerful computers but not like supercomputers. They can support hundreds or thousands of users at the same time.
  3. Minicomputers: These are scaled-down versions of mainframe computers. They can also support up to around 200 users simultaneously.
  4. Micro-computers (personal computers): These are small computers that are designed to be used by one user at a time, they are then divided into desktops and laptops.

Tianhe-2 in National Supercomputer Center in Guangzhou

A Supercomputer

A Supercomputer

The Computer Keyboard Is an Input Device

As a computer learner, you need to know more about the keyboard and mouse because you will be interacting with them a lot. The keyboard is an input device that will help you enter raw data into your computer. We have different types of keyboards based on their layouts but their mode of operation is basically the same.

The keyboard as an input device contains a number of keys that are pressed in order to enter the desired data into the computer. These keys are arranged in a specific way on your keyboard.

  • Typewriter keys (alphabetic keys)
  • System keys
  • Application key
  • Function keys
  • Numeric keypad
  • Cursor control keys
  • Enter keys

Keyboard Layout

The QWERTY Keyboard

The QWERTY Keyboard

The Numeric Keypad

It is positioned on the extreme right-hand side of the keyboard. It contains:-

  • Num Lock: For turning on and off the numeric keypad.
  • / Forward Slash: Used for calculations dealing with the division.
  • * The asterisk: Used for multiplication.
  • - Subtraction sign: used for subtraction (difference) calculations.
  • + Addition sign: used for summing.
  • Enter key: Also known as the return key - it is an alternative to clicking on the okay button. Used in a word processor, it will take you one line down.
  • Numbers 0–9.
  • Numeric/Punctuation Keys: These are the series of keys on top of the alphabetical keys.

Special Keys on the Keyboard

  • Caps lock (for capital letters).
  • Tab key (for indenting a paragraph).
  • Shift key (Shifts from uppercase characters to the lower case and vice versa and helps us to type the characters on top of any key with two sets of characters.)
  • Return key or Enter key (Help us to go to the next paragraph).
  • Control key: (ctrl) When pressed with another key, it performs a special operation.
  • Alternate key: (alt) Used to change the function of other pressed keys and the results will vary depending on the program.
  • Backspace: For deleting (erasing) characters to the left of the cursor.
  • Spacebar: Used for creating a space while typing.
  • Windows logo key: once pressed it brings out the start menu.
  • Page up: For scrolling through pages that are above the current page.
  • Page down: For navigating through pages that are down the current page.

Qwerty Keyboard

Qwerty Keyboard Layout

Qwerty Keyboard Layout

The Mouse

The mouse is an important input device used generally in computers for pointing, clicking and dragging. The most common types of mice have got three buttons.

Terms Used While Working With the Mouse

  1. Click: Clicking (depressing) the left mouse button once.
  2. Double click: clicking twice on the mouse left button.
  3. Triple-click: clicking thrice on the left button.
  4. Right-click: clicking on the right mouse button.
  5. Dragging: clicking and holding on the mouse button.

Left mouse button

  • Used to select by clicking once.
  • To highlight by clicking, holding down the left button and then dragging on the text you want to select.
  • For moving items by clicking, holding on and then dragging them.
  • For issuing commands to the computer.

Right Mouse Button

  • Get information from the computer (retrieving)
  • Creating shortcuts to / moving items.

Scroll Button

It is usually situated between the right and left buttons. It is used for scrolling or navigating through an open document. Or simply put, moving the contents of a page up or down.

A USB Computer Mouse

A Computer Mouse

A Computer Mouse

Starting the Computer

For you to be able to use a computer, you must turn it on. The monitor and the system unit of a desktop computer must be turned on. You should be able to locate the power button for both of them. The modern electronic equipment uses the same symbol a zero (0) and a one (1) inserted on it to denote the power on and off button. Just have a look at the symbol on your Mobile's on / off button to get the picture. After locating the power button, turn on the system unit, and then turn on the monitor (there is no particular order, you can start with any). Just press the button in and release it.


Once you power on your computer, you should be able to see some text and graphics appearing on your screen. Be patient and wait for your computer to load/boot/start.

Booting is the process by which the computer loads the system files into the main memory in readiness for use. In simple terms, it is the start-up process of a computer.

Power Button

On-off Power Button

On-off Power Button

Introduction to Computers

This article is accurate and true to the best of the author’s knowledge. Content is for informational or entertainment purposes only and does not substitute for personal counsel or professional advice in business, financial, legal, or technical matters.

© 2012 Patrick Kamau


Frank Fiamor, This is a very insightful literature on the introduction to computers.Thank you. on October 17, 2019:

A good guide.

Patrick Kamau (author) from Nairobi, Kenya on September 25, 2012:

Teresa Schultz, thank you for your encouraging comment. I mean, you understand where I am coming from and what I want to achieve by coming up with these 'back to basics guides'. Initially, I thought it is only in Africa that we are technologically challenged, but I have come to realize these challenges are world-wide. I also did my computer basics like 7 years ago, I am glad that now I am earning online. My aim is to help others to learn about computers so that they can utilize them to the maximum.

Thanks for the vote, share and visit. All the best.

Teresa Schultz from East London, in South Africa on September 25, 2012:

Excellent hub for beginners using computers. So many people seem to think most people already know about how to use computers or what the different parts of a computer are for, and yet there are also so many out there who are still scared of using computers because they don't understand them, or fear that they won't understand them so they don't even try to understand them. Yet computers are so useful especially for those trying to earn an extra income or trying to work from home. I like that you include info about starting the computer. 6 years ago I knew nothing about computers and didn't even know where to find the start button! Voting up and sharing. Well done.

Patrick Kamau (author) from Nairobi, Kenya on May 02, 2012:

Thanks josiejossy, for the vote. Glad that you enjoyed reading the hub. Remember to check the others too.

josiejossy from Nairobi Kenya on May 02, 2012:

Great hub, very informative, thanx for sharing, voted up