A computer is an electronic machine which is able to execute multiple sets of mathematical or logical instructions automatically. Modern computers are able to perform generic sets of instructions called run-time applications. These applications enable computers to do a wide array of tasks automatically. Computers have various kinds of storage media in which data is stored such as RAM, floppy disk, hard disk and others. There are also several kinds of input and output devices through which data is passed to and from the computer such as keyboard, mouse, monitor and others.


The computer consists of different kinds of microprocessors and central processing units (CPU) which are responsible for performing various arithmetic and logical operations. The main components of the computer are microprocessors and mainframe which are located at different locations. The operating system on a personal computer includes operating system software and hardware. Some important hardware components include: random access memory (RAM), processors, central processing units (CPU) and hard disk. The operating system and software are used to control and manipulate the computer programs.

The computer consists of different types of devices which are used to store and retrieve information and to execute its logical operations. These include: Random Access Memory (RAM), Central Processing Unit (CPU), Computer Architecture Hardware which includes motherboard, attached machines, USB and more. Nowadays, it is used in different forms such as: desktop, laptop computers, netbooks, workstations, servers and communication appliances. A desktop computer is a personal computer that is built desktop-based and that does not incorporate any kind of storage media or input device.

A laptop computer is an electronic device that is smaller than a personal computer. It runs on batteries, AC power and AC adapter. It has either a CPU or a discrete graphics card and either a hard disk or an input device such as a mouse or a touch screen. It is used for connecting to a network or to a storage device such as a CD or a DVD player.

Netbooks are small, lightweight electronic devices which can either be used in the place of a computer or in addition to one. Examples include notebook type computers that are smaller than a standard laptop and that run on batteries. Netbooks have their own input device such as a USB pen or a printer. Examples include netbooks that run on lithium-ion batteries, other electronic devices like a Sigma watch or a camera. Other electronic devices include wireless phones that run on wireless networks or on memory card.

One of the most vital pieces of hardware in a desktop computer is the hard disk. Hard disks store data files. The size and capacity of hard disks vary according to the needs of the user. Desktop computers usually have fast access to the internet and to files. Laptops, on the other hand, are used for web browsing and for running mobile programs. A laptop computer may be used as a storage device but not as a computer.