The Four Categories of Computer Hardware

Updated on February 2, 2018
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Alfred is a long-time teacher and computer enthusiast who works with and troubleshoots a wide range of computing devices.

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.

Computer hardware refers to the physical devices that make up a computer. Examples include the keyboard, monitor and disk drive.

Hardware devices can be classified into four distinct categories:

  • Input devices: For raw data input.
  • Processing devices: To process raw data instructions into information.
  • Output devices: To disseminate data and information.
  • Storage devices: For data and information retention.

1. Input Devices

Components which are used to input raw data are categorized under input devices. They aid in feeding data such as text, images, and audiovisual recordings. They even aid in file transfers between computers.

The keyboard is probably the most commonly used input device. Below are just some other types of input devices.

A microphone is an example of a sound input device.
A microphone is an example of a sound input device.
Input Type
Pointing Device
Mouse, touchpad, touchscreen, multi-touch screen, pen input, motion sensor, graphics tablet, interactive smartboard, and fingerprint scanner.
Game Controller
Joystick, gamepad, and steering wheel.
Audio Input Device
Microphone and midi keyboard.
Bluetooth Peripheral
Keyboard, mouse, headset, gamepad, printer.
Visual and Imaging Device
Webcam, digital camera, digital camcorder, TV capture card, biometric scanner, and barcode reader.
Network Device
Ethernet hardware and Bluetooth/wireless hardware.

2. Processing Devices

Processing is the core function of a computer. It is the stage where raw data is transformed into information. Once data has been processed, it can be used for useful purposes.

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 processor cache and 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:

  • 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: The ALU is responsible for all arithmetic and logic operations like addition, multiplication, subtraction, division, and comparison logic operations.
  • Register and cache: These are storage locations inside the processor that respond to the instructions of the control unit by moving relevant data around during processing.

An AMD microprocessor is an example of a processing device.
An AMD microprocessor is an example of a processing device.

3. Output Devices

Hardware components that disseminate and display both data and information are classified under the output category.

Output is the culmination of a cycle which starts with the input of raw data 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, like printouts of paper and 3D models.

The CRT monitor is an output device.
The CRT monitor is an output device.

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

See results

Popular Softcopy Devices

Visual display devices include:

  • Monitor
  • Projection display
  • Interactive (electronic) smartboard
  • Touchscreen

Sound devices include:

  • Speakers
  • Headphones and earphones

Network input/output includes:

  • Ethernet cables
  • Wireless and Bluetooth transmissions

USB input/output includes:

  • Flash drives
  • External drives
  • Optical drives

Popular Hardcopy Devices

Impact printers include:

  • Dot matrix printer
  • 3D printer

Non-impact printers include:

  • Inkjet printer
  • Laserjet printer
  • Thermal printer

A 3D printer
A 3D printer | Source

4. Memory/Storage Devices

Components that retain/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 refers to random-access memory (RAM) but can also refer 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 them as required.

Computer memory devices.
Computer memory devices.

Secondary memory is labeled as such 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 a RAM device for processing to take place.

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

To give some examples of these devices, primary memory includes:

  • DRAM
  • SRAM
  • ROM

Secondary memory is subdivided into two categories:

  • Internal devices are designed to be placed inside the computer at all times. Examples include hard disk and solid state disk drives.
  • External devices are plug and play media used to transfer files between computers. Examples include optical disks, flash disks, and external disk drives.

Questions & Answers

    © 2014 Alfred Amuno


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        YUSUF AUWAL 2 days ago


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        Kalilu kamara 2 weeks ago

        Thanks very much sir I learned something new

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        Alfred Amuno 2 weeks ago from Kampala

        Happy that you learned something Gladys

      • profile image 2 weeks ago

        Thanks. It has really helped me.

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        ANKIT KUMAR 3 weeks ago

        It's very helpful for student

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        Jamilu HUssaini Baba Jarmai 4 weeks ago

        I am very much indepted

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        Dak Chuol Dhuor 7 weeks ago

        It help a lot and give your more knowledge in hardware computer.

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        MARTHA 8 weeks ago


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        Miracle 2 months ago

        This is wow! I salute you man. the article is much helpful. I really do appreciate. Thanks a lot.

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        luke 2 months ago

        this a lot of good info

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        The mn 2 months ago

        i ctrl-c and ctrl-v so much....... ty

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        Larry Enticer 3 months ago

        OMG this Helped ME nothing Not at All

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        Alfred Amuno 4 months ago from Kampala

        Thanks for appreciating Caleb

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        Caleb Kiprotich seth 4 months ago

        This a very good combination of Computer Basic Skills Which are useful ...Thanks for this plausible and fantastic ideas

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        Scolah 4 months ago

        Nice article and well explained.

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        Krittika Rasiah 4 months ago


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        cithy Ephraim 5 months ago

        Indeed this page is fully contained with all necessary guidelines for basic applications of this course . Thanks


      • profile image

        cithy Ephraim 5 months ago

        Indeed this page is fully contained with all necessary guidelines for basic applications of this course . Thanks


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        abduselam sul 5 months ago

        thanks for sharing agreat article

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        Ciplak 5 months ago

        great's help me to know more about computer hardware..thanks dude

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        Muhammad Abdullah 5 months ago

        write down the four types of computer briefly explain?

      • amuno profile image

        Alfred Amuno 6 months ago from Kampala

        Thanks Chad, hope it really is beneficial to the young fellows.

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        Chad Crouch 6 months ago from South Africa

        Nice article for learners. Very well structured. Good work.

      • Viral Prajapati profile image

        Viral Prajapati 7 months ago from Ahmedabad

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

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        Grace kaonga 8 months ago

        well explained have surely enjoyed

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        Lucia 8 months ago

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

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        Mona Sabalones Gonzalez 9 months ago from Philippines

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

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        ronielyn 9 months ago

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

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        Kingsley Aghedo 10 months ago

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

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        Pinky Mahadeo 11 months ago

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

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        Ashir Mubeen 11 months ago

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

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        Harindi 12 months ago

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

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        Well expalined. I really gained a lot. 13 months ago


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        kelvin tatenda chirefu 13 months ago

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

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        tulise 14 months ago


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        aqs 16 months ago

        Thaks for sharing such type of useful information.

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        Alfred Amuno 17 months ago from Kampala

        Thanks Maggie for appreciating.

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        Maggiesanchez 17 months ago

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

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        Alfred Amuno 18 months ago from Kampala

        Quite true Chad

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        Chad Crouch 18 months ago from South Africa

        Great article. Can help young lads with homework.

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        Janu Cap 19 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 19 months ago

        helped with my hw

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        Alfred Amuno 20 months ago from Kampala

        Thanks Penny

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        penny 20 months ago

        it awesome summary

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        Alfred Amuno 21 months ago from Kampala

        Good to know Phoebe

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        phoebe faraon 22 months ago

        A glad to see to know the info in your computer

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        Alfred Amuno 22 months ago from Kampala

        Glad to know the info was helpful

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        AS"LMFlkdlhdo 22 months ago

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

        Thank you !

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        Marck 22 months ago

        Ty vm

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        Alfred Amuno 2 years ago from Kampala

        Thanks for appreciating Sya

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        sya 2 years ago

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

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        Alfred Amuno 2 years ago from Kampala

        Thanks for appreciating Farida

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        Farida Achieng 2 years 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.