Sam+Butcher



My coursework will be collected in next lesson. I need to spend 50 minutes on it. An input device is a piece of hardware that is used to enter data into a computer. The keyboard is the most common and widely used input device. Most keyboards are called 'QWERTY' keyboards. This name comes from the first six letters on the top row of the alphabet keys.

Advantages

 * Most computers come with a keyboard supplied
 * People are used to using keyboards to enter data, they need very little training
 * A skilled typist can enter data very quickly
 * Specialist keyboards are available e.g. ergonomic, gaming keyboards

Disadvantages
Everyone is familiar with a computer mouse; along with the keyboard, it is one of the most common input devices you will use. A mouse usually has two buttons, a right and left one and also a central wheel which allows you to scroll up and down the page (some mice have three or four buttons).
 * It is easy to make mistakes when typing in data
 * If you can't touch type, it can be time consuming to enter data
 * Keyboards are not suitable for creating diagrams
 * Disabled people often find keyboards difficult to use
 * Excessive use can lead to R.S.I.

Advantages

 * Ideal for use with desktop computers
 * Usually supplied as part of a new computer system
 * Most computer users are familiar with them and require little training
 * Works well in conjunction with a keyboard for data entry

Disadvantages
A touchpad is an input device which is usually found on a laptop computer. Because a laptop is meant to be portable, people aren't always able to attach a traditional mouse, it might be too much hassle or there might not be enough room to use one. A touchpad can be used in place of a mouse.
 * They need a flat space close to the computer
 * The rollers in mice that use balls can become clogged with grease and grime and lose their accuracy until cleaned.
 * Overuse can lead to RSI

Advantages

 * Useful for laptops when using a mouse isn't practical
 * The pad's position is fixed compared to the keyboard, unlike with a traditional mouse
 * Very short finger movements are required to move the cursor

Disadvantages

 * Takes practice and skill to control the position of the cursor using the touchpad
 * Gloves cannot be worn i.e. in a cleanroom environment
 * Moist, sweaty or calloused fingers can disrupt the signals picked up by the sensors.

Joysticks were originally used by pilots as part of an aeroplane's controls and the technology was developed to let computer gamers experience a more realistic game environment. You can move joysticks in many directions and the joystick tells the computer which direction it has been moved into. They also have one or more buttons whose position when pushed can be read by the computer.

Advantages

 * They give a better gaming experience for racing or flying styles of computer games

Disadvantages
A monitor (or screen) is the most commonly used output device. They come in many different shapes, sizes and forms. In an exam question, you will need to be able to choose the best type of monitor and then explain your reasons Printers are another common output device. They are used to create a 'hard' copy of your work i.e. something that you can hold, hand to someone else or file away. Laser printers are used in many workplaces because they are quiet, they print a large number of sheets very quickly and they produce high quality documents.
 * Some people find joysticks more difficult to control than a traditional mouse.
 * Joysticks are not particularly robust and can break easily if too much force is used on them.

Data can be stored either in the 'internal memory' or on a 'storage device'. The amount of data and instructions that can be stored is measured in 'bytes'. One byte contains 8 bits (short for Binary Digit). This is the smallest unit of data that can be stored. Each 'bit' is represented as a binary number, either 1 or 0. A single keyboard character such as the letter A or T takes one byte of storage. ROM is a special kind of memory which stores the instructions which the computer uses when it 'boots up' How many times have you worked for a whole lesson on something which you were just about to save but then the computer crashed or your mate 'accidentally' switched it off. When you rebooted and logged back in, your work was gone forever.