- Motherboard - It is the "body" or
mainframe of the computer, through which all other components
- Central processing unit (CPU) -
Performs most of the calculations which enable a computer to function,
sometimes referred to as the "brain" of the computer.
- Computer fan - Used to lower the
temperature of the computer; a fan is almost always attached to the CPU, and
the computer case will generally have several fans to maintain a constant
airflow. Liquid cooling can also be used to cool a computer, though it focuses
more on individual parts rather than the overall temperature inside the
- Random Access Memory (RAM) -It is
also known as the physical memory of the computer. Fast-access memory that is
cleared when the computer is powered-down. RAM attaches directly to the
motherboard, and is used to store programs that are currently running.
- Firmware is loaded from the Read
only memory ROM run from the Basic Input-Output System (BIOS) or in newer
systems Extensible Firmware Interface (EFI) compliant.
As its name suggests, firmware is somewhere between
hardware and software. Like software, it is a computer program which is
executed by a microprocessor or a microcontroller . But it is also tightly linked to a
piece of hardware, and has little meaning outside of it.
- Internal Buses - Connections to
various internal components.
- PCI (being phased out for graphic
cards but still used for other uses). The Peripheral Component Interconnect, or PCI
Standard, specifies a computer bus for attaching peripheral devices to a
computer mother board. Typical PCI cards used in PCs include: network cards,
sound cards, modems, extra ports such as USB or serial, TV tuner cards and
- PCI-E or Peripheral Component
Interconnect Express, officially abbreviated as PCI-E or
PCIe, is a computer expansion card interface format introduced by Intel
in 2004. PCI Express was designed to replace the general-purpose PCI expansion
bus, the high-end PCI-X bus and the AGP graphics card interface. Unlike
previous PC expansion interfaces, rather than being a bus it is structured
around point-to-point serial links called lanes.
- Universal Serial Bus (USB) is a serial bus standard to
interface devices to a host computer. USB was designed to allow many
peripherals to be connected using a single standardized interface socket and
to improve the plug-and-play capabilities by allowing hot swapping, that is,
by allowing devices to be connected and disconnected without rebooting the
computer or turning off the device. Other convenient features include
providing power to low-consumption devices without the need for an external
power supply and allowing many devices to be used without requiring
manufacturer specific, individual device drivers to be installed.
- 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.
- CSI - The Intel QuickPath
Interconnect or simply "QuickPath"
(the official legal name for Common System Interface or "CSI")
is a point-to-point processor
interconnection being developed by Intel, as a competitor to HyperTransport.
QuickPath technology also includes an integrated memory controlle. It is
expected to be released in late 2008 and will first be used by Intel's Nehalem
and Tukwila processors.
- AGP - The Accelerated Graphics
Port (also called Advanced Graphics Port) 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.
Since 2004, AGP is being progressively phased out in favor of PCI-E
- 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
II. 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 AT and BabyAT (old) but the standard for PCs
actually are ATX and Micro ATX.
III. Storage controllers
Controllers for hard disk,
CD-ROM and other drives like internal Zip and Jaz conventionally for a PC are
IDE/ATA; the controllers sit directly on the motherboard (on-board) or on
expansion cards, such as a Disk array controller. IDE is usually integrated,
unlike SCSI Small Computer System Interface which can be found in some servers.
The floppy drive interface is a legacy MFM interface which is now slowly
disappearing. All these interfaces are gradually being phased out to be replaced
by SATA and SAS.
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
- 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
- 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-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
- 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.
VI. Internal storage
Hardware that keeps data inside
the computer for later use and remains persistent even when the computer has no
- Hard disk - for medium-term storage of data.
- Solid-state drive - a device similar to hard disk, but containing no
- Disk array controller - a device to manage several hard disks, to achieve
performance or reliability improvement.
VII. 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
- 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.
IX. Other peripherals
In addition, hardware devices can include
external components of a computer system. The following are either standard or
Input1.1 Text input devices
1.2 Pointing 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
- Mouse - a pointing device that
detects two dimensional motion relative to its supporting surface.
1.3 Gaming devices
- Trackball - a pointing device
consisting of an exposed protruding ball housed in a socket that detects
rotation about two axes.
- 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
1.4 Image, Video input
- Game controller - a specific type
of controller specialized for certain gaming purposes.
- Image scanner - a device that
provides input by analyzing images, printed text, handwriting, or an
1.5 Audio input devices
- Webcam - a low resolution video
camera used to provide visual input that can be easily transferred over the
- Microphone - an acoustic sensor
that provides input by converting sound into electrical signals
Video output devices