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TechKnowSurge Catalog Videos What Is a computer?
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What Is a computer?

A computer is any device that accepts input, processes data, produces output, and stores information — a definition that covers everything from calculators and smartphones to smartwatches and televisions. This content establishes that foundational definition and explores how binary numbers drive the processing behind everyday computing devices.

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About this video

A computer is any device that takes in data, processes it, produces a result, and stores information — and that definition covers a much wider range of technology than the desktop or laptop most people picture. Smartphones, smartwatches, calculators, home automation systems, and even modern televisions all meet that criteria, sharing the same fundamental four-function architecture: input, processing, output, and storage. The abacus, which allowed users to manipulate beads to perform calculations, is often cited as an early precursor to this concept, illustrating that the core idea of structured data processing predates electronic technology by centuries. At the hardware level, modern computers perform all processing in binary. A calculator provides a clear, accessible illustration of this: when a user enters a decimal number, the device internally converts it to binary, routes it through an integrated circuit for calculation, and then converts the binary result back to decimal for display on the LCD screen. This input-to-binary, process, binary-to-output cycle is the same fundamental sequence running inside every computing device, regardless of form factor or complexity. Input and output devices are the points where humans and computers exchange information. Keyboards, mice, microphones, and webcams each convert physical actions or analog signals into binary data that the processor can work with, while monitors, headphones, and printers translate processed binary data back into human-readable or perceptible form. Some hardware, such as network interface cards and touchscreen tablets, handles both directions simultaneously. Storage devices — including USB drives, solid-state drives, and SD cards — extend the architecture by preserving data beyond active processing sessions, whether on the device itself or transferred between systems.

What you'll learn

What's covered

What Is a Computer?

Aligned to

CompTIA Tech+
1.3 Illustrate the basics of computing and processing.
2.6 Compare and contrast common computing devices and their purposes.
2.1 Classify common types of input/output device interfaces.
2.5 Compare and contrast storage types.
Cisco CCST IT
2.3 Assist end users in locating, identifying, and understanding ports and cables.
CompTIA A+ Core 1
3.3 Given a scenario, select and install storage devices.

Key terms

Computer
An electronic device that performs four core functions: input, processing, output, and storage of data.
Input
Data or signals entered into a computer for processing, such as keystrokes, mouse movements, or sound waves.
Output
The result produced by a computer after processing input, such as images displayed on a monitor or audio played through headphones.
Storage
The component of a computer that retains data for later use, such as a USB drive, solid state drive, or SD card.
Processing
The stage in computing where input data is manipulated or calculated, typically performed by a computer's central circuitry.
Network Interface Card
NIC
A hardware component that connects a computer to a network.

Topics

Computer Fundamentals Input Output Storage Binary Numbers Data Processing Computing Devices

Transcript

From an Abacus to a Laptop

What I have right here is called an abacus. They have these little beads on it that you can shuffle back and forth. What people use this for is that they can shuffle these back and forth to help them calculate certain information, calculate data. Some consider this as being the first computers. It's not the electronic computers that we think of nowadays, however some consider this being the precursor to what computers are now.

Certainly an abacus isn't a modern computer like my laptop is, or my tablet — it is a computer as well. Same thing with my cell phone: cell phones are computers. Same thing with my watch. My home automation is a computer as well. Even these two TV sets that you see in the background are modern computers.

The Four Functions

So what ties this all together? What is the commonality between all of these different objects?

Computers are said to have four main functions. There's some sort of input. There's a process that happens, a calculation that happens. And then there's an output. Another function that's part of computers is some sort of storage that happens with the processing.

Modern computers are usually all done electronically nowadays. This means that even this simple calculator is a form of computer. I can do 2 + 2 — it just accepted my input. I can hit equals and it will calculate, and then it has an output: it's showing me four. It also has a memory, so I can actually store this number in a memory.

Calculating in Binary

Modern computers usually process in binary. For instance, this calculator right here, when I'm pressing the two on here it shows a two, but it shows it in decimal format, not binary format. When I'm doing the calculation in the background, in the circuitry of this, it's actually doing that all with binary numbers.

On my calculator, when I press 2 + 4, what's happening is the calculator is actually seeing that in binary form. It's seeing it as 00 1 0 for the two and 1 0 0 for the four. Now I'm going to hit the equal sign, and that's when it actually does the processing. It's going to send it through its integrated circuit on the board, and then it will pop out with an answer, and that answer is going to be in a binary number — it's going to be one 0 one0. The next thing that it needs to do is display it, so it shows me a six in decimal form. It converts it back into a decimal form to be displayed on this little LCD readout here.

Examples of Input

One example of input into a modern computer is your keyboard. Your keyboard has a bunch of different characters on it, and when you press one of those characters it will convert that into a binary number and then send it to the processor to be processed.

A mouse will record the movement as it glides across the surface, and then it will convert that into a binary number and then send it to your computer to be processed.

A microphone on your computer is going to take the sound waves and convert them into a binary equivalent, then to be sent to your computer to be processed.

A webcam will take your image and turn it into a digital equivalent and then send it to your computer to be processed.

Examples of Output

There's also a lot of examples of outputs, such as headphones. Where I want to listen to audio, what will happen is those digital signals get converted back into sound waves and then are played through my headphones so I can listen to them. Or perhaps my monitor, so that I can see what's happening on my computer. Or a printer, so I can print out a copy of the output.

Devices That Do Both

There's also some equipment that does both input and output. An example might be a network interface card. I'd plug this ethernet into my network interface card so I can connect it to other computers or to get onto the internet. What happens is, when I want to go to a website, it sends bits — these binary numbers — down this cable and makes a request, and then that comes back to my computer, my computer interprets it and then displays it on the screen.

Another example of a piece of equipment that does both input and output is my tablet right here. This tablet shows my presentation, but it also has an input to it. It has the screen, which is an output, and then the input is my pen, where I can draw on my presentation.

Storage

There's lots of different ways we could store data as well. One example might be a USB drive, where I can transfer data from one device to another. It could be a solid state drive, which typically stays on the computer. Or it could be an SD card, which I transfer information back and forth between my cameras and my computer.

So computers have some sort of input, they process that data, they have an output, and there's a storage component to it.

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