Hardware Overview

Computer hardware is the physical part of a computer system. This contrasts with software, which runs on the hardware but is not physical. It is however stored on the hardware.

Computers make up only a small part of the computer hardware being sold. Microprocessors in automobiles, audio systems, microwave ovens and many other devices make up well over 90% of all computing devices.

The typical personal computer consists of a case and the following components:

• a motherboard to which most other components connect. It is contained inside the case.
• a central processing unit (CPU) performs most of the processing is directly connected to the motherboard.
• random access memory (RAM) is attached directly to the motherboard and the programs that are currently running are stored in RAM while they are running. When the computer is booted the contents of RAM (if any) are erased and the operating system is loaded.
• read only memory (ROM) contains software that must be available when the computer boots up. ROM is also used by various components to contain software that will not change.
• busses are pathways that are used to connect various components.
• power supply supplies power to the rest of the computer.
• controllers can be built in to the motherboard or can be separate circuit boards (cards) connected via slots on the motherboard. They are used to produce and/or transmit data to various devices such as magnetic or optical disks, video display units, sound systems, networks, ....
• removable media devices (CD/DVD drives/burners, flash drives, floppy drives, tape drives, ...)
• internal storage (hard disks, solid-state drives, ...)
• input devices (keyboards, pointing devices, game controllers, scanners, ...)
• output devices (monitor, printer, speakers, ...)

Further Info

Wikipedia article on computer hardware (link)
howSTUFFworks hardware video (link)