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The Four Major Categories of Computer Hardware

Updated on September 17, 2017
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Alfred is a long-time teacher and computer enthusiast who works with and troubleshoots a wide range of computing devices.

Computer hardware refers to the tangible components that make up a complete computer. Be it a tablet, laptop or desktop, the overriding hardware functionality remain the same albeit the differences in shape, size and design.

In order to understand hardware better, it is imperative to break them down into four distinct categories:

  • Input devices: to input raw data.
  • Processing devices: to process received instructions into usable information.
  • Output devices: to disseminate processed data and information.
  • Storage devices: to store data and information for future use.

An illustration of a typical desktop computer set  comprising all the hardware components
An illustration of a typical desktop computer set comprising all the hardware components

1: Input Devices

Components which are used to input raw and other data are categorized under input devices.

They aid in feeding raw and other data such as text, images and audiovisual recordings; or even aid in file transfer between computers.

This data is then manipulated by the processor.

A microphone is an example of sound input device
A microphone is an example of sound input device

The following is a list of commonly used input devices:

  • Keyboard - perhaps the most widely
  • Pointing devices:

Multi touch screen
Pen input
Motion sensor
Graphics tablet
Interactive (electronic) smartboard
Fingerprint scanner

  • Game controller devices:

Steering wheel

  • Audio input devices:

Midi keyboard

  • Bluetooth peripherals


  • Visual and Imaging devices:

Digital camera
Digital camcorder
Tv capture card
Biometric scanner
Barcode reader

  • Network devices:

Ethernet hardware
Wireless/Bluetooth hardware

(Read more about input devices)

2: Processing Devices

Processing is the core function of the computer. It is the stage where raw data is transformed into useful information. Components that manipulate data into information are categorized under processing.

The microprocessor is the major device in this category. It works closely with primary memory during its operations. Data is stored temporarily in primary memory during the processing period.

The microprocessor is subdivided into three important units, which work together in order to accomplish its function. The units are:

  • Control unit
  • Arithmetic and logic unit
  • Register and cache

An AMD microprocessor is an example of a processing device
An AMD microprocessor is an example of a processing device
  • The Control Unit

It manages and supervises the operations of the processor and other components that are crucial in data manipulation.

  • Arithmetic and Logic Unit (ALU)

The ALU is responsible for all arithmetic and logic operations like addition, multiplication, subtraction, division and comparison logic operations.

  • Registers and Cache Memory

These are storage locations inside the processor, which respond to the instructions of the control unit by moving relevant data around during processing.

(Read more about processing devices)

3: Output Devices

Hardware components that disseminate and display both data and information are of the output device category.

This stage is the culmination of a cycle which starts with raw data input and processing.

These components are sub-categorized under softcopy and hardcopy output.

Softcopy output includes the intangible experience. The user derives visual satisfaction by reading a message through display components or listens to audio files through speakers.

On the other hand, hardcopy output devices are tangible printouts like paper and 3D models.

A collection of old CRT monitors. The CRT monitor is an output device
A collection of old CRT monitors. The CRT monitor is an output device

Do you still have a CRT monitor somewhere in your house?

See results

Popular softcopy devices

  • Display

Projection display
Interactive (electronic) smartboard

  • Sound

Headphone and earphone

  • Network input/output

Ethernet cables
Wireless and Bluetooth transmissions

  • USB input/output

Flash drives
External drives
Optical drives

Popular hardcopy devices

  • Impact printer
Dot matrix printer
3D printer
  • Non-impact printer

Inkjet printer
Laserjet printer
Thermal printer

(Read more about output devices)

4: Memory\Storage Devices

Components that store data are classified under memory\storage devices.

Storage is sub-divided under primary and secondary memory and is either volatile or nonvolatile.

Primary memory usually means random access memory (RAM) but also refers to all memory that works in tandem with the processor. RAM is volatile meaning that it retains data only when the computer is powered up.

The central processing unit (CPU) or accelerated processing unit (APU) reads instructions stored in this memory and executes the instructions as required.

Computer memory devices
Computer memory devices

Secondary memory is secondary because data stored within secondary storage media (usually disk drives) do not communicate directly with the microprocessor. Any data stored in such media is first transferred to RAM for processing to take place.

This type of memory is also non-volatile since it permits long time storage as opposed to volatile memory.

  • Primary memory
  • Secondary memory

Secondary storage is sub-divided into two distinct categories. Internal and external storage.

Internal devices are designed to be placed inside the computer at all times i.e. hard disk and solid state disks

External devices are plug and play media used to transfer files between computers i.e. optical disks, flash disks and external disk drives.

(Read more about memory devices)

© 2014 Alfred Amuno


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    • Viral Prajapati profile image

      Viral Prajapati 3 weeks ago from Ahmedabad

      Great way to explain here..All basic and important information are cover with video and images, It's a really good..

    • profile image

      Grace kaonga 4 weeks ago

      well explained have surely enjoyed

    • profile image

      Lucia 5 weeks ago

      Its a great note. Its what I was needing for solve a problem

    • grand old lady profile image

      Mona Sabalones Gonzalez 2 months ago from Philippines

      wow, you sure know your techiness). I bow before you.

    • profile image

      ronielyn 2 months ago

      thank you very much for the good was a big help! ty

    • Kingsley Aghedo profile image

      Kingsley Aghedo 3 months ago

      Very nice presentation. I am a computer guru myself. Your pictures of a computer really drive home your points.

    • profile image

      Pinky Mahadeo 4 months ago

      I have learnt so much, also knows more about the hardware and its categories. Am so thankful

    • profile image

      Ashir Mubeen 4 months ago

      This information is pretty awesome. It helped me a lot. Following you.

    • profile image

      Harindi 5 months ago

      This was very helpful me to do my university assignment.Thank you very mush

    • profile image

      Well expalined. I really gained a lot. 5 months ago


    • profile image

      kelvin tatenda chirefu 6 months ago

      thank you so much man its so helping . i have learnt a lot from your work keep it up .

    • profile image

      tulise 7 months ago


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      aqs 9 months ago

      Thaks for sharing such type of useful information.

    • amuno profile image

      Alfred Amuno 10 months ago from Kampala

      Thanks Maggie for appreciating.

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      Maggiesanchez 10 months ago

      Great work men!! i'm glad since i have got to understand more abt hardwares.CONGRATS!!!!!

    • amuno profile image

      Alfred Amuno 11 months ago from Kampala

      Quite true Chad

    • ChadCrouch profile image

      Chad Crouch 11 months ago from South Africa

      Great article. Can help young lads with homework.

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      Janu Cap 12 months ago from Ha Noi

      Thanks for Alfred Amuno! Glad to know the info was helpful. Follow you and follow you. Thanks friends

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      lol 12 months ago

      helped with my hw

    • amuno profile image

      Alfred Amuno 13 months ago from Kampala

      Thanks Penny

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      penny 13 months ago

      it awesome summary

    • amuno profile image

      Alfred Amuno 14 months ago from Kampala

      Good to know Phoebe

    • profile image

      phoebe faraon 15 months ago

      A glad to see to know the info in your computer

    • amuno profile image

      Alfred Amuno 15 months ago from Kampala

      Glad to know the info was helpful

    • profile image

      AS"LMFlkdlhdo 15 months ago

      The information Was Prety Awsome I almost Get all The Correct Answers For My Assignment

      Thank you !

    • profile image

      Marck 15 months ago

      Ty vm

    • amuno profile image

      Alfred Amuno 17 months ago from Kampala

      Thanks for appreciating Sya

    • profile image

      sya 17 months ago

      it good note. good for student to the homework..

    • amuno profile image

      Alfred Amuno 20 months ago from Kampala

      Thanks for appreciating Farida

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      Farida Achieng 20 months ago

      I have learnt allot and it has enabled me to gain more and learn more about the hardware and its categories .Am so grateful.