COMPUTER HARDWARE

A computer consists of two broad categories of components: hardware and software. Computer

hardware includes all of the physical components that make up the system unit plus other devices

connected to it. These connected devices are referred to as peripheral devices because they are

outside, or peripheral to, the computer. Examples include a monitor, keyboard, mouse, hard disk

drive, camera, and printer. Some peripheral devices, such as the monitor and hard disk drive, are

essential components of a personal computer system. Categories of hardware devices include the

system unit, input devices, output devices, storage devices, and communication devices.

System Unit

The system unit is a relatively small plastic or metal cabinet that houses the electronic components,

which process data into information. Inside the cabinet, the main circuit board, called the

motherboard, provides for the installation and connection of other electronic components. Once

installed on the motherboard, the components can communicate with each other, thereby allowing

the processing of data into information. The motherboard has two components, the central

processing unit (CPU), also called the microprocessor (or simply processor), and the internal

memory. The processor consists of one or more electronic chips that read, interpret, and execute

instructions that operate the computer and perform specific computing tasks. When a program is

executed, the processor temporarily stores the program’s instructions and the data needed for the

instructions into the computer’s memory. Memory, also called primary storage, consists of small

electronic chips that provide temporary storage for instructions and data during processing.

Input Devices

An input device is a hardware device that allows users to enter program instructions, data, and

commands into a computer. The program or application being used determines the type of input

device needed. Common input devices are the keyboard, mouse, and microphone.

Output Devices

An output device is a device that makes information available to the user. Popular output devices

include display screens (monitors), printers, television screens, and speakers. Some output devices,

such as a printer, produce output in hard copy (tangible) form, such as on paper or plastic. Other

output devices, such as a monitor, produce output in soft copy (intangible) form that can be viewed

but not physically handled.