The QWERTY keyboard - Sample Essay
This useful device is one of the main and most commonly used input devices. This device is attached to the computer and is used for writing on the computer. The typical keyboard used by most people is the ‘QWERTY’ keyboard. It is called ‘QWERTY’ as these are the first letters in the first row. There are newer keyboards with different designs but most people are familiar with the ‘QWERTY’ keyboard. A man called Sholes in 1878 developed this keyboard layout. It was originally developed for the typewriter but now is the standard layout for the computer.
There are four main parts to a keyboard and they are the main keyboard, numeric keypad, cursor keys and function keys. An advantage Most computers have this device attached to it and a skilled typist can enter data very quickly. A disadvantage It can be very time consuming to enter data this way, especially if you have not had much practice at typing. It could also cause cramps in the fingers. The mouse is the most common pointing device. People commonly use a mouse on a small mat and the mouse has a small cursor on the computer. This small cursor called a pointer follows your movements on screen.
With this pointer you can select options using icons or menus on screen. To select the icons people will have to click on the 2 or 3 buttons on the mouse. The left button is most used out of the 2 or 3 buttons. Most mice have a small ball located underneath it. This ball detects your movements. As it detects your movements the small ball is also rotating. The mouse monitors how much the ball is turning and in which direction it is moving. As the mouse does this, it sends this information to the computer so that it can move he pointer.
An advantage People find it easier to select items and start tasks by clicking icons or choosing form menus rather than typing in commands. A disadvantage Mouse balls can become very dirty and stop functioning correctly unless cleaned regularly. A touch pad is just like a mouse but is used on laptops. Just like the mouse the touch pad a small cursor on a laptop screen. A touch pad works by sensing the users finger movement and downward pressure. As it detects finger movements the pointer, on screen, will move wherever the users finger will move on the touch pad.
Like on mice, there are buttons but on touch pads there are buttons but you really don’t need to use them. On laptops you can select an icon or menu just by tapping on the touch pad. This happens by the surface of the touch pad sensing your tapping of the finger. George E. Gerpheide invented the touch pad in 1988 and in 1994 a company called Apple computer was the first to license a touch pad on its portable computers. Today touch pads are the most used pointing devices on laptops. An advantage It is quick and easy selecting icons or menus just by tapping on the touch pad An disadvantage.
The surface of touch may tend to be a bit slippery. A tracker ball or trackball is another pointing device for laptops, this time the device isn’t a built in device. It looks just like small ball from underneath a mouse but this time is facing upwards. The trackball is usually located in front of the keyboard toward the person using it. A tracker ball has a socket, which it is placed it so half the ball is inside the laptop and half is facing outwards. Using a trackball isn’t difficult at all and all a user has to do is roll the ball to direct the pointer, the small cursor on screen, to the icon or menu.
Then to select the icon or menu the user has to place the pointer there and click one of two buttons, which is identical to mouse button. An advantage Like an ordinary mouse, you can not like lose the ball as it is built in to the device as in mice u can open the device to let the ball out. A disadvantage First time users can find it difficult to use. A joystick is used to play computer games. A standard joystick has up to right directions. The joystick sends information to the computer in which direction it is being pulled.
After it tells the computer this, the computer uses this information and for example moves the steers the car to the left. There are also several buttons around the joystick as well. These buttons have particular functions to do as well for example in a car game one button will sound the horn or trigger a missile or something like that. There are two types of joysticks; they are called the analogue joystick and the track point device. The analogue joystick, whilst it is being moved, measures how far it is being pulled. It does this because in an analogue joystick the further you pull the stick the faster the object goes.
A track point device is a small joystick and is sometimes built into laptops as another pointing device. An advantage There is an immediate feel of direction due to the movement of the stick. A disadvantage They are not particularly strong and can break easily when used with games software. A video digitiser is a software device, which captures from analogue video still frames. It then converts it to a digital still image. It gets these images from a TV set, video camera, or video recorder, etc. , and forwards them to a computer for display, storage, or general manipulation.
This kind of technology is done with the aid of computer hardware. Video digitiser come in colour and it also can capture moving video sequences as well as stil images. An advantage Allows us to capture real life images which are often more appropriate than drawing. A disadvantage A fast computer with a large memory capacity is required to cope with a large amount of data involved. A digital camera is used in the same way as an ordinary camera and it even looks like an ordinary camera but it has many different qualities. Digital cameras don’t use film like the ordinary camera but they use loads if light sensors built inside it.