Computers: What They Are, How They Work, Essential Parts


Computers are perhaps one of the greatest, if not the greatest, marvels of the 20th century. They’ve become such a big part of our everyday lives that it’s nearly impossible for any society or any individual to function without them. But, aside from knowing how to use them, have you ever wondered how do computers work?

In this article, we’ll try to explain computers and how they function. You won’t become a computer expert after reading this, but you should at least get a working knowledge about how these devices run.

What Is a Computer?

So, how do computers actually work? Before we dive into the details, let’s begin by defining what a computer is. Technically speaking, a computer is a machine that can be programmed to carry out sequences of arithmetic and logical operations by itself, drawing information from binary data to execute an intended outcome.

Here’s a more simple definition. A computer is simply a machine that manipulates information. It does so by reading a series of ones and zeros (binary) and translating them into usable output that can be read by humans. In practice, behind the Tweet you just posted is a complex arrangement of ones and zeros. This is where the term “digital” comes from.

So that laptop you’re working on, that smartwatch on your wrist, the phone you’re carrying, and even the system that controls the traffic lights when you cross the street, are all working on computers fundamentally running through a series of ones and zeros.

Did you know: Experts project that even money will be digital in the future, as cryptocurrency rises in popularity and starts to compete with fiat money.

What Does a Computer Consist of and How Does It Work?

Now that you have an idea about how computers work in general, let’s talk about what a computer consists of. A computer consists of many systems that work together. When put together, they make up your computer. There are many parts of a computer, but these five are the most essential ones:


That’s where everything begins – the mainboard. It’s also known as the motherboard, baseboard, main circuit board, or system board. If you’re referring to an Apple computer, this is called a logic board.

The mainboard is the biggest board inside the computer case. It’s a printed circuit board to which every other essential part is connected. This is where you mount everything else, from the processor, graphics card, and memory to peripherals like monitors and printers. Think about it like a pizza. The mainboard is the crust, and every other ingredient is put on top of it. Without the crust, there’s nothing to hold the sauce, cheese, salami, and all the other ingredients together.

There are many types of mainboards and each is designed to work with different types of parts as well. What’s important is that every part is compatible with each other.

Central Processing Unit

The central processing unit, or CPU, is also referred to as the brain of the computer. It is the part, primarily responsible for computing processing, or executing the instructions of a computer program. Remember the ones and zeros? CPUs are the ones that translate these binary digits into the output you experience.

CPUs follow a three-stage function: fetch, decode, and execute. The first stage, fetch, is when it receives information or instructions that it is supposed to do. These instructions are in raw form and still need to be processed or decoded for the system to know what to do. After the information has been translated or decoded, the processor will send it back out for execution. This execution is what you will experience as a user. These are the visuals you see and the sounds that you hear.

Graphics Processing Unit

This is actually a part that basic computers can function without. The graphics processing unit, also known as GPU, is basically responsible for delivering better graphics. And when we say better, it means that a computer without an extra GPU can actually deliver basic graphics, but toss in a GPU and the difference can be as night and day.

We’ve decided to include the GPU in this essential list since most computer uses nowadays involve demanding visuals. If you’re a gamer, graphics cards are definitely a must as many AAA gaming titles will only run properly with a GPU. For non-gamers, graphics cards serve those doing any personal computer work such as 3D modeling or any other activity that involves other resource-intensive applications.

Random Access Memory

Random-access memory is also called volatile memory but is more often referred to as RAM. This is one of the two memories on the computer. The job of RAM is to store data temporarily. When you open an application, active data is stored in RAM for easy access and retrieval.

If it sounds too abstract for you, think about it this way. If you have a tool cupboard in your garage, that’s basically where you keep all your tools when you’re not fixing your car. It serves as storage space for the tools you are not using at the moment. But once you have to work on your car, you’ll have to get the tools you need out and put them in a tray that you can put beside you when you go under the vehicle. This way, you have access to the tools you need while you work and just return them all to the cupboard once you’re done.

In working computers, RAM is that tray where you put all those tools you take with you. It gives you quick access while you’re working so you don’t have to keep getting up to return the wrench to the tool cupboard only to use it five minutes later. RAM is also a big contributor to speeding up your computer.


Storage, as its name suggests, is where all applications are stored. It is sometimes confused with memory which we’ve just explained in the preceding segment. Both storage and memory work hand in hand, but function in very different ways.

If we use the same example to explain RAM, storage would be the tool cupboard where you store all your tools. Storage holds all the data in your computer, from the operating system it is based on and the apps you use to create documents to the fonts installed on your word processor. In a nutshell, it is where all software is kept.


For a computer to work and be used by humans, it needs peripherals where users can make inputs and receive outputs, so we might as well include them in this list.

  • Monitor – the monitor is the computer’s output device that displays information visually for the user to be able to see it.
  • Keyboard – the keyboard is the main input device through which users can send instructions to the computer using alphabetical and numerical characters.
  • Mouse-like the keyboard, the mouse is also an input device. The difference is that the mouse controls a cursor that can be seen on the screen and that you can use to navigate through the various pages and click on the content you need.
  • Power Supply – supplies electricity from the wall socket to every part of the computer.

Key Takeaways

The mainboard is the part where everything is mounted; it connects all other essential parts.
The CPU is also known as the brain of the computer and it’s responsible for processing the computer’s instructions by fetching, decoding, and executing information.
The GPU supports applications that have significant graphics demands.
RAM is where data is stored temporarily for quick access.
Storage is where all software used to run your computer is kept.

What Is the Difference Between a PC and a Laptop?

If you’re just following the etymology, both a PC and a laptop are personal computers in that they are machines that serve you on a personal basis. PCs are large, multi-piece machines meant to be used on tabletops. They are separately made up of a computer chassis, monitor, keyboard, mouse, and sound systems. In a laptop, sometimes called a notebook, depending on the size, all these parts make up one single unit. As the name suggests, a laptop is small enough to be used on your lap.

So which should you get? To answer this, you have to decide which computer’s function you would prioritize more – power or portability?

At the same price point, PCs will always be much more powerful. This is because it’s a lot more expensive to make the same hardware specs in a smaller and more compact form. Another thing worth considering is that PCs can be upgraded. You can easily swap parts for better and more updated ones which you cannot do on many laptops that often come with parts soldered together. Also, you can even assemble your own PC from scratch, whereas laptops are only sold as-is.

If you’re planning to use a computer mostly on your desk and performance is important to you, PCs are definitely the way to go. If you like the idea of being able to use your computer wherever you go and have the extra money to get higher specs, then laptops are the better choice for you.

Other Relevant Terms

For further understanding how computers work, here are some other relevant terms that you should be familiar with:

  • Binary System & Data

As already mentioned before, computers use binary (digits of one and zero) as a language. While there are many computer languages such as Python and JavaScript you might have heard of, they all boil down to binary at the very basic level.

  • Operating System

Essentially the most important software on any computer. The operating system or OS is what manages all memory, processes, as well as all software and hardware on the computer. You may be familiar with Windows, macOS, and Linux. These are all different operating systems created by different computer companies.

  • Hardware & Software

A computer has two components. These are the hardware and the software. The hardware consists of the physical, tangible components like the disks and the chips, while software refers to the intangibles like programs, OSs, and applications.

  • Applications & Programs

Applications and programs are software that is designed to do specific computer process tasks. These include word processors, photo editing tools, and games.

Did you know: The first computer was about 15 meters long and weighed five tons.


A computer is a machine that can be programmed to do specific tasks using binary language. Computers consist of a mainboard, central processing unit (CPU), graphics processing unit (GPU), random access memory (RAM), and storage.

When choosing a computer, you can opt for either a PC or a laptop. PCs are bigger, cheaper, and stationary, while laptops are compact, more expensive, and mobile.


What can computers do?

In the early days of computers, computer work was as simple as solving basic math problems. Nowadays with far more sophisticated coding, computers can do almost anything from making an entire movie to driving a car.

Can I live without having to use a computer?

If you’re simply implying human survival, then the only things you really need are the basics – food, water, and shelter. But that would also mean that you’ll have to isolate yourself from society. For anyone to thrive in a normal setting and keep up with modern civilization, computer literacy is as important as learning how to speak.

How do computers work at the most basic level?

A computer functions using a language called binary which is a combination of ones and zeros. There are many programming languages being used these days, but when it comes to the very basics, they can all be stripped down to binary.

What makes a computer work?

So, how do computers work? Computers are made up of a sum of many parts. Each part has its own specific function. These consist of the hardware, which is the tangible physical components like the drives and memories, and the software, which includes all the intangible applications like word processors and spreadsheets.

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