Devices of a desktop computer can be classified into two categories - input devices and output devices. Both of them together build a relationship between a computer and the external world. Input devices are the part of the hardware mechanism of the computer that changes information to make it acceptable by the computer. However, this information is completely under the user control that uses them to give commands or concepts that has to be processed by the computer.
There are different types of input devices. We have classified them according to the duration of the time period. Earlier, there were only different types of keyboards that are included in the category of input devices of computer. Like there are computer keyboards, chorded keyboard and keyer in the category of input devices only. But later on, with technological advancement, pointing devices were developed and got added in the types of input devices.
A pointing device is a hardware device that makes it possible for the user to install constant and multi-dimensional information in the system. The three main functions of the pointing devices are - to point somewhere on the monitor, click and drag. Motion of the pointing device on the table is followed by the movements on the screen. The most common pointing device about which everybody knows is the mouse. However, there are some other pointing devices as well and now, we will discuss about them.
Track ball is a pointing device that is mounted in the shape of ball in between the two mounts of the mouse. When the user rolls the track ball, the information on the monitor starts rolling either in the downward direction or in the upward direction. Another pointing device is the touch pad. It is generally used in the laptops. They are in the shape of a flat pad where rubbing finger leads to movement of cursor on the screen.
Space ball is used for the 3-D computer designs and is used by graphic professionals. Touch screen is also a pointing device which acts as a display and the device at a same time. User just needs to point over the screen of the computer to give it the desired directions. A light pen is also a pointing device. It is light sensitive device and is used to point out the displayed things on the computer.
Joysticks are the hand held devices that are used to handle video games on computer in the best way while pointing stick is used to touch the monitor for the computer for giving it commands and directions. And the last pointing device that is used quite commonly is the wired glove. By using the wired glove device, the wearer can give the directions to the computer by bending his fingers.
So, these were some of the pointing devices for the desktop as well as the laptop computers. More than half of them are used in our day to day lives while others are used for official professional purposes only.