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Overview of Computer System Unit Parts

Patrick, a computer technician, is a dedicated writer who wishes to make the world better by informing individuals who seek more knowledge.

The Computer System Unit

The system unit is the box-like case that contains the electronic components of a computer. Many people erroneously refer to this as the CPU. Here you will find devices like the power supply, different drives, the fan, the connectors, and the motherboard. Note that in most cases, the monitor, keyboard, and mouse will not be found inside the system unit layout.

Other names for the system unit include the computer chassis, cabinet, box, tower, enclosure, housing, or simply case.

Parts of the Unit

These are some of the major components you are going to find inside your system unit. If you are thinking of checking some of these parts out, make sure your computer is powered off and disconnected from a power source. Be careful not to mess with your components if you are not very familiar with them. Before touching anything, be aware of the ESD precautions.

A Computer Base Unit

Computer System Unit

Computer System Unit

The Motherboard

The motherboard is sometimes called the system board or main board. It is the main circuit board of a microcomputer. This component contains the connectors for attaching additional boards. All other parts connect in one way or another to the motherboard.

This part typically contains the CPU, BIOS, memory, mass storage interfaces, serial and parallel ports, expansion slots, and all the controllers required to control standard peripheral devices, such as the display screen, keyboard, mouse, and disk drive.

When you are reading about motherboards, you won't fail to come across the term motherboard form factors, which describes the general shape, the type of case, and the power supply it can use. It also describes the physical organization of the motherboard.

A Labeled Motherboard

A Labeled Motherboard

Hard Disk Drive

A hard disk drive is a high capacity, non-volatile, magnetic data storage device with a volume (disk) that is usually non-removable.

Data is magnetically read and written on the platter by read/write heads that float on a cushion of air above the platters.

Hard Disk Drive

Hard Disk Drive

Floppy Disk Drive

This is a disk drive that can read and write floppy disks, although they are obsolete nowadays.

These drives have been replaced by the USB flash disk drives in modern machines.

Diskette Drive

Diskette Drive

Power Supply Unit

The power supply unit (PSU) is used to convert AC currents from the main supply to the different DC voltages required by various computer components.

Power supplies are quoted as having a certain power output specified in watts, A standard power supply would typically be able to deliver around 350 watts.

You will need more power from the power supply if your PC has more operating components.

Power Supply Unit

Power Supply Unit

CD-ROM Drive

This is a high capacity optical data storage device with a removable disk. It writes data onto or reads data from a storage medium.

A CD-ROM drive may be connected to the computer via an IDE (ATA), SCSI, S-ATA, Firewire, or USB interface or a proprietary interface.

A CD Rom Drive

A CD Rom Drive

How to Identify the Components Inside Your Computer

Your Opinion

This article is accurate and true to the best of the author’s knowledge. Content is for informational or entertainment purposes only and does not substitute for personal counsel or professional advice in business, financial, legal, or technical matters.

Questions & Answers

Question: What are the parts of a computer system unit?

Answer: These are the major components that you will find when you open the computer system unit. Note that the computer system unit is the box-like structure that people erroneously refer to as the CPU. Inside the system unit, expect to find; the motherboard, hard disk drive(s), optical drive(s), power supply unit, and in some old systems fan and floppy disk drive.

Question: Are the parts described in this articles those you see inside the system unit?

Answer: That is very true. In this article, we are having an overview of the different components or parts of the system unit. The system unit is the box-like case that contains the electronic components of a computer. Many people erroneously refer to this as the CPU. Here you will find devices like the power supply, different drives, the fan, the connectors, and the motherboard.

© 2010 Patrick Kamau


JAIRUS BENARD on February 14, 2020:

Thanks for that enriching tutorial, thanks

Patrick Kamau (author) from Nairobi, Kenya on September 18, 2019:

Hello Adam. Computer problems occur both in software and hardware area. Fault finding is handled depending on the problematic part. For instance, a small problem where the mouse is not functioning, you will have to start checking the connectivity.

Adam on September 14, 2019:

After knowing all about the components and working of a computer. Here I've a question that is how to detect a fault if any part of my computer is not working. So, how can I detect and fix it?

Lunzoo on August 25, 2019:

Useful tips

Char on August 04, 2019:

What are the reasons when computer screen is black and won’t open or respond?

Olaoluwa BleezPrint on May 07, 2019:

Exceptionality is here. So love it!!!

Usman Bara'u Yanmota on March 18, 2019:

This piece has really been very helpful to me and my students. Thank you so much.

dante gulapa on March 13, 2019:

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jjajjangmyeon on February 27, 2019:

nice profile lol


dick face on January 20, 2019:

i dont careeeeeeeeeeee

Patrick Kamau (author) from Nairobi, Kenya on December 17, 2018:

Thanks, Mr. Yussif you are much welcome. Keep reading to get more knowledge. All the best in your endeavors.

Yussif Yakubu Suhuyini Tace on December 16, 2018:

Sincerely greatful brother. May god bless you knowledge. Thanks!

adam on November 08, 2018:

good job thank you guys

Stephen on October 18, 2018:

Nice piece. Thank you

Elinam on October 04, 2018:

Thank you it really helpful

Cyrus on September 23, 2018:


Patrick Kamau (author) from Nairobi, Kenya on September 20, 2018:

You are the people who keep us going Adam Abdul Fatawu. Thanks a lot.

Adam Abdul Fatawu on September 19, 2018:

Thanks so much. It really helped me out... Much appreciation for your service

me on September 17, 2018:

thanks ;)

axaiben on June 26, 2018:

can you give the important parts of a system unit?

yanna on June 20, 2018:

can you please give us some information about parts of computer system

Muzdha on June 19, 2018:

Can you give me all the information about system unit not a little bit

Can on April 06, 2018:

Can you give me all the parts of the system unit and not some?

D on March 28, 2018:

Thanks this was helpful but I want to ask questions. How do I do it

isaac wetosi on March 26, 2018:

nice presentation

John Dave on March 06, 2018:

Thank you for these information this is very helpful for my study in Philippine and I'm Filipino

rudzani frans lukhele on January 23, 2018:

thanks guys i got the answer now

bahog bisong on December 10, 2017:

very helpful sir.. thank you for posting these..

Patrick Kamau (author) from Nairobi, Kenya on October 31, 2017:

Thanks, Bofa Deez for visiting and reading this tutorial. I am happy that you found it useful.

Bofa Deez on October 31, 2017:

I found this article very helpful thank you

Patrick Kamau (author) from Nairobi, Kenya on October 09, 2017:

Thanks, shelly, I am glad you learnt something from this article.

shelly on October 08, 2017:

this was helpful thank you

imee zuasola on August 07, 2017:

thank you for posting the parts of the system unit!!!!

Patrick Kamau (author) from Nairobi, Kenya on August 31, 2016:

Thank you Ziel for the visit and comment. I am happy that you have found the content of this hub useful. Keep reading!

Patrick Kamau (author) from Nairobi, Kenya on February 29, 2012:

eunice, you are welcome. Thanks for reading and commenting.

eunice on February 29, 2012:

thaks for the knowledge

Patrick Kamau (author) from Nairobi, Kenya on January 29, 2012:

Thanks Mohamed Dhidha. I like enlightening people about computers. There is a lot to learn from the computer world.

Mohamed Dhidha on January 29, 2012:

The information was presented in a very good format, very interesting and very helpful. Thank you so much.

Patrick Kamau (author) from Nairobi, Kenya on January 16, 2012:

You are welcome chrysann Evans. It my pleasure to find that you are contented by what I am offering here.

chrysann Evans on January 15, 2012:

thanks for your help

Patrick Kamau (author) from Nairobi, Kenya on December 06, 2011:

Thanks Abrabanj, for going through this useful information. There is a lot to learn in the computer world.

Abrabanj on December 06, 2011:

A nice and very good expression system unit

Patrick Kamau (author) from Nairobi, Kenya on October 08, 2011:

Thanks AMUZU for reading and commenting.

AMUZU on October 08, 2011:

well done

Patrick Kamau (author) from Nairobi, Kenya on September 19, 2011:

Thank you stasheen brown for dropping by, check more of my hubs for a lot of helpful information.

stasheen brown on September 12, 2011:

thank you for all the information. very helpful :)

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