A computer is an electronic machine which is programmed to carry out certain sequences of logical or arithmetic operations automatically. Modern computers are able to execute almost all kinds of mathematical functions; they are called ‘computational’ computers. These computers are used in various industries and for various applications. Modern computers can do virtually all kinds of functions; they can perform audio, image processing, spreadsheet processing, web browsing, word processing and so on.
Computers are generally divided into two main groups: computers based on hardware and computers based on software. The hardware-based computer refers to the ones which are based on main processors like motherboards, CPU, sockets, cards, drives etc. On the other hand, the software based computer refers to the ones which are based on external memory, input devices like keyboard, mouse, pointing device etc. The modern computers have many ports and many types of output devices. The ports vary from one model to another and the type of output devices varies with the make of the computer. The input and output devices in a computer to determine the amount of computing power available to it.
Desktop computers and laptops are some of the smallest types of computers. They are ideal for performing simple calculations and also for storing data. Desktop computers differ from laptop computers in that a desktop computer has fixed display screen and keyboard and does not use batteries for operation. A laptop uses batteries for operation and can be attached to a power outlet.
Laptops are portable and small in size. They have greater computing power because they have more input devices and output devices and they are usually connected to the internet for online surfing and downloading. Many laptop computers come with a touch screen and are equipped with a pointing device.
Netbooks, as netbooks are called, are smaller than desktop computers but are still quite large compared to laptops. Smaller in size and less expensive than laptop computers, netbooks are ideal for carrying along in case of travel. They can connect to the internet using a wireless network.
As mentioned above, there are many different types of personal computer. Each type has its own functions and is useful for different types of applications. Desktop computers are for basic computing needs, laptops are for wireless Internet access and Netbooks are small and convenient for carrying along. The different types of computers available can be categorized into personal computers, mainframe computers and embedded computers.