What Are the Main Parts of a Computer?

It doesn’t matter if it’s a laptop, a desktop, a smartphone or a tablet, the devices we use today are all made up of similar functioning parts—just arranged together to fit into different-sized containers.

The word, “computer”, gives us an idea of what it really is—hint: it computes.  A computer is simply a device that uses computations to solve problems and perform tasks we program it to perform.

The CPU

The Central Processing Unit (CPU) is the major part of the computer and does all of the “heavy lifting” so to speak. CPUs process binary data. Think of binary information as simply a yes or a no. If I asked you, “Did you eat the entire jelly sandwich?”, the answer could be a, “Yes.” or a, “No”. That’s how computers think, only it’s not yes’s and nos, it’s an electric voltage or no voltage.

So think of a series of wires, all carrying voltages or some not carrying any voltage, but all acting together as one unit. You could then take that information and store that group of wires (those carrying voltages can have that information stored as a 1 and those not carrying a voltage can have that stored as a 0). That series of 0s and 1s can be used to represent something like a letter or a number, etc. And that’s exactly how it works. A CPU manipulates binary information (0s and 1s) and produces output.

For example, if a computer was instructed to add 1 + 1 (which would equal 2), it would add the two binary numbers below together to get the number, 2, and store the result in binary form as well.

You might see something like 2 written on the screen, but rest assured that the number is being stored in a different form inside the computer, using a series of 0s and 1s.

So, 00000001 is the number 1 in a binary system (and 00000010 is the number 2)

0 0 0 0 0 0 0 1   + 0 0 0 0 0 0 0 1  = 0 0 0 0 0 0 1 0 

The CPU could actually store the number 1 (in binary code) in a register, within it, and the other number 1, in another register, and finally store the result, 2, in a separate register.  Yes, your CPU can do operations like this well over a billion times per second (which makes it seem like things are being done at the same time, but they are actually being done just very fast).

Where does your computer store all of this information once it finishes processing it?

The Hard Drive

Before you even turn on your computer there needs to be programs (all ready stored on it) to boot up the computer and get everything ready to go.  The operating system on a computer (such as Windows for Microsoft and MacOS for Apple) is already stored on the hard drive of a computer to help the computer with fundamental tasks that is needs to operate.  Anything that your computer needs in its long term or permanent memory—think of that as being stored on the hard drive.

If you want to store pictures of your family or documents on your computer, they are stored in a way that they don’t go away when you turn off your computer, this is non-volatile memory.  So if you want to store lots of videos and large files, in a permanent way, on your computer, in addition to the operating instructions needed for your computer, you will need a hard drive that can accommodate your storage needs.

That is why you see so many cloud services popping up with the ability to store data in a cloud (on someone else’s servers) and allow you to access that data anytime you want—they help with folks who want additional storage because their hard drives may not have enough space.

Memory seems pretty important, since CPUs and other programs use it to store and process the information your computers needs to execute tasks. Is there any other way your computer accesses memory?

Random Access Memory (of RAM)

Yes, is the short answer to the above question. Your computer uses temporary memory to run things that aren’t required to be stored permanently. For example, let’s say you want to play a video game on your computer or write a document in a word processor. You don’t need every aspect of the game or word processor active when you’re not using the programs. You also don’t need those programs to start up your computer. What your computer does is store information into temporary storage to use when operating certain programs. When the program is off, or your computer is turned off, the computer erases that memory and it is available for you to use, again, when you turn on your computer or when you start up that program.

For example, you don’t need access to the special fonts inside of a word processing program, when you are not using that program, that would take up unnecessary space on your computer that could be used for other tasks. But, when you do need that program and you decide to open it, you will want all of its “bells and whistles” to be available to you.

RAM is referred to as volatile memory because it is only used during the running of the program and is removed once the computer is turned off.  Having more RAM allows you to have more programs “open” and running seemingly, at the same time.

How Do We Make All of These Things Fit Inside of a Computer?

The Motherboard

How would all these parts be useful if they weren’t connected together in some systematic way (i.e., the wires, the electrical currents, the CPU, the RAM, the hard drive, etc.)?  This where the motherboard comes in.  

The motherboard is the foundation that holds the computer together.  It takes power in from the power supply, it allows different parts to communicate with each other, it holds some of the main parts of a computer in place (in some instances items are welded onto the motherboard), and it allows us to expand the functionality of our computer through the addition of expansion slots.

The motherboard is thus the foundation that holds the key parts together.

Other Items

There are other items that can make up your computer, like a mouse that can be added to support a desktop computer, or a monitor that can be used to display the content on your computer, or a cooling system that’s inside—near the important parts—to make sure all of these items don’t overheat.

Computers come with many parts to help them perform calculations, transmit data, store information and output results onto your screen.

Now, let’s get into programming, as that will help us tell a computer what to do.