A computer is basically a machine which is able to execute mathematical or logical operations automatically by the use of stored instructions. Modern computers are able to do very complex series of operations called applications. These applications enable computers to do a vast array of functions. A computer has four general parts. The microprocessor stores the instructions which are to be executed in the computer CPU. The memory which is also called RAM is the place where data and instructions are stored and retrieved whenever a program is executed.


The hard disk holds data that is accessed when the user wants to retrieve a file from the disk. It is the most inexpensive part of the computer and it is used almost on a daily basis. The optical disc, which is CD-ROM is also a storage device in personal computers. Digital video camcorders record video and audio information and store them in the disc. Compact disks are used to store large files in the computer.

There is another component known as the computer hardware which includes motherboard, processor unit, central processing unit or CPU, hard disk drive, graphic input device or graphics card and sound card. All these parts of a desktop computer are necessary for performing tasks but they are not interchangeable with other machines. Desktop computers consist of four main types of components. These types are namely desktop computer, notebook computer, laptop computer and workstation computer.

IBM is one of the world leaders in manufacturing personal computers. They have built wide ranges of computers for different types of needs. IBM models are known to be user friendly. IBM is known to provide good quality laptops. The IBM models have a number of options available when it comes to their storage capacity and speed. These options include traditional, high performance, ultra-high performance, workstation, small business, educational, big business and enterprise.

Apple is also a major manufacturer of Apple computers. A variety of Apple computers are manufactured by Apple including iPod, iMac, Mac mini, and many more. Apple computers are known for being user friendly and having stylish designs. The apple computer runs on the x operating system platform. Apple has produced great quality laptops.

A variety of companies have designed a variety of personal computer models including Dell, Gateway, Toshiba, HP, Sony, Lenovo, and several others. Some of the companies produce laptops that have an integrated display screen whereas others have built-in displays. Laptops from these companies can perform all functions, but they differ in the type of input device that comes with them.