Caribbean Secondary Education Certificate - Information Technology/Functions of Hardware Components of a Computer System

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Functions of Hardware Components

Quick overview of pc hardware.jpg

A typical personal computer consists of a case or chassis in a tower shape (desktop) and the following parts:


  • Motherboard - It is the "body" or mainframe of the computer, through which all other components interface.
  • Central processing unit (CPU) - Performs most of the calculations which enable a computer to function, sometimes referred to as the "backbone or brain" of the computer.
    • Computer fan - Used to lower the temperature of the computer; a fan is almost always attached to the CPU.
  • Firmware is loaded from the Read only memory eg. ROM run from the Basic Input-Output System (BIOS) or in newer systems Extensible Firmware Interface (EFI) compliant
  • Internal Buses - Connections to various internal components.
  • PCI (being phased out for graphic cards but still used for other uses)

PCI Local Bus (usually shortened to PCI), or Conventional PCI, specifies a computer bus for attaching peripheral devices to a computer motherboard.

  • PCI Express (Peripheral Component Interconnect Express), officially abbreviated as PCIe (PCI-E is also commonly used), is a computer expansion card standard introduced by Intel in 2004, and currently is the most recent and high-performance standard for expansion cards that is generally available on modern personal computers.
  • Industry Standard Architecture (in practice almost always shortened to ISA) was a computer bus standard for IBM compatible computers.
  • Universal Serial Bus (USB) is a serial bus standard to interface devices to a host computer.
  • HyperTransport (HT), formerly known as Lightning Data Transport (LDT), is a bidirectional serial/parallel high-bandwidth, low-latency point-to-point link that was introduced on April 2, 2001.
  • The Intel QuickPath Interconnect ("QuickPath", "QPI")is a point-to-point processor interconnect developed by Intel to compete with HyperTransport. Prior to the announcement of the name, Intel referred to it as Common System Interface or "CSI".
  • The Accelerated Graphics Port (also called Advanced Graphics Port, often shortened to AGP) is a high-speed point-to-point channel for attaching a graphics card to a computer's motherboard, primarily to assist in the acceleration of 3D computer graphics.
  • The VESA Local Bus (usually abbreviated to VL-Bus or VLB) was mostly used in personal computers. VESA Local Bus worked alongside the ISA bus; it acted as a high-speed conduit for memory-mapped I/O and DMA, while the ISA bus handled interrupts and port-mapped I/O.
  • External Bus Controllers - used to connect to external peripherals, such as printers and input devices. These ports may also be based upon expansion cards, attached to the internal buses.

Power Supply

A case control, and (usually) a cooling fan, and supplies power to run the rest of the computer, the most common types of power supplies are mechanic shed (old) but the standard for PCs actually are ATX and Micro ATX.

Video Display Controller

Produces the output for the visual display unit. This will either be built into the motherboard or attached in its own separate slot (PCI, PCI-E, PCI-E 2.0, or AGP), in the form of a Graphics Card.

Removable Media Devices

  • CD (compact disc) - the most common type of removable media, inexpensive but has a short life-span.
  • CD-ROM Drive - a device used for reading data from a CD.
  • CD Writer - a device used for both reading and writing data to and from a CD.
  • DVD (digital versatile disc) - a popular type of removable media that is the same dimensions as a CD but stores up to 6 times as much information. It is the most common way of transferring digital video.
  • DVD-ROM Drive - a device used for reading data from a DVD.
  • DVD Writer - a device used for both reading and writing data to and from a DVD.
  • DVD-RAM Drive - a device used for rapid writing and reading of data from a special type of DVD.
  • Blu-ray - a high-density optical disc format for the storage of digital information, including high-definition video.
  • BD-ROM Drive - a device used for reading data from a Blu-ray disc.
  • BD Writer - a device used for both reading and writing data to and from a Blu-ray disc.
  • HD DVD - a high-density optical disc format and successor to the standard DVD. It was a discontinued competitor to the Blu-ray format.
  • Floppy disk - an outdated storage device consisting of a thin disk of a flexible magnetic storage medium.
  • Zip drive - an outdated medium-capacity removable disk storage system, first introduced by Iomega in 1994.
  • USB flash drive - a flash memory data storage device integrated with a USB interface, typically small, lightweight, removable, and rewritable.
  • Tape drive - a device that reads and writes data on a magnetic tape,used for long term storage.

Internal Storage

Hardware that keeps data inside the computer for later use and remains persistent even when the computer has no power.

  • Hard disk - for medium-term storage of data.
  • Solid-state drive - a device similar to hard disk, but containing no moving parts.
  • Disk array controller - a device to manage several hard disks, to achieve performance or reliability improvement.

Sound Card

Enables the computer to output sound to audio devices, as well as accept input from a microphone. Most modern computers have sound cards built-in to the motherboard, though it is common for a user to install a separate sound card as an upgrade.


Connects the computer to the Internet and/or other computers.

  • Modem - for dial-up connections
  • Network card - for DSL/Cable internet, and/or connecting to other computers.
  • Direct Cable Connection - Use of a null modem, connecting two computers together using their serial ports or a Laplink Cable, connecting two computers together with their parallel ports.

Other Peripherals

In addition, hardware devices can include external components of a computer system. The following are either standard or very common.


  • Text input devices
    • Keyboard - a device to input text and characters by depressing buttons (referred to as keys), similar to a typewriter. The most common English-language key layout is the QWERTY layout.
  • Pointing devices
    • Mouse - a pointing device that detects two dimensional motion relative to its supporting surface.
    • Trackball - a pointing device consisting of an exposed protruding ball housed in a socket that detects rotation about two axes.
  • Gaming devices
    • Joystick - a general control device that consists of a handheld stick that pivots around one end, to detect angles in two or three dimensions.
    • Gamepad - a general handheld game controller that relies on the digits (especially thumbs) to provide input.
    • Game controller - a specific type of controller specialized for certain gaming purposes.
  • Image, Video input devices
    • Image scanner - a device that provides input by analyzing images, printed text, handwriting, or an object.
    • Webcam - a low resolution video camera used to provide visual input that can be easily transferred over the internet.
  • Audio input devices
    • Microphone - an acoustic sensor that provides input by converting sound into electrical signals


  • Image, Video output devices
    • Printer
    • Monitor
  • Audio output devices
    • Speakers
    • Headset


Computer Hardware