Computer hardware - Definition and Overview

Hardware comprises all of the physical parts of a computer, as distinguished from the data it contains or operates on, and the software that provides instructions for the hardware to accomplish tasks. The boundary between hardware and software is slightly blurry—firmware is software that is "built-in" to the hardware, but such firmware is usually the province of computer programmers and computer engineers in any case and not an issue that computer users need to concern themselves with.

A typical computer (personal computer, PC) contains in a desktop or tower case (chassis) the following parts:

• System board/Motherboard which holds the CPU, Random Access Memory and other parts, and has slots for expansion cards
  • RAM (Random Access Memory)- for short term data-storage, so the computer doesn't have to fish through the hard drive to find something. More RAM can contibute to a faster PC
  • Buses:
    • PCI bus
    • ISA bus
    • USB
    • AGP
• power supply - a case that holds a transformer, voltage control and fan
• storage controllers, of IDE, SCSI or other type, that control hard disk, floppy disk, CD-ROM and other drives; the controllers sit directly on the motherboard (on-board) or on expansion cards
• video display controller that produces the output for the computer display
• computer bus controllers (parallel, serial, USB, Firewire) to connect the computer to external peripheral devices such as printers or scanners
• Some type of a removable media writer:
  • CD - the most common type of removable media, cheap but fragile.
    • CD-ROM
    • CD-RW
    • CD-R
  • DVD
    • DVD-ROM
    • DVD-RW
    • DVD-R
  • Floppy disk
• Internal storage - keeps data inside the computer for its later use.
  • Hard disk - for long-term storage of data.
  • Disk array controller
• Sound card - translates signals from the system board into a language that the speakers can read, and has terminals to plug in speakers.
• Networking - to connect 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.
• Other peripherals

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

• Input
  • Keyboard
  • Pointing devices
    • Mouse
    • Trackball
  • Joystick
  • Gamepad
  • Image scanner
  • Webcam
• Output
  • Printer
  • Speakers
  • Monitor
• Networking
  • Modem
  • Network card

See also

• Computer architecture
• legacy system
• Open hardware
• optical computer
• DNA computer
• History of computing hardware
• Origins of computer terms

External links

• DebianWiki: Hardware (http://wiki.debian.net/index.cgi?Hardware)
• Computer Hardware Directory @ dmoz (http://www.dmoz.org/Computers/Hardware/)
• Definition of hardware at eLook Computing Reference (http://www.elook.org/computing/hardware.htm)
• Definition of Computer hardware @ Webopedia (http://www.webopedia.com/TERM/H/hardware.html)
• Computer Discussion Forums (http://www.tech-forums.net)