What is input/output?


by Miriam Tocino

We always talk about the many things that we, computers, can do. But under the hood, we're always doing the same four basic things:

1️⃣ First, we take in some information.
2️⃣ Then, we store it.
3️⃣ We process it.
4️⃣ And finally, we send out something else!

You could also say that we input information, do something with it, and output some other information as a result.

Now, let's look at one example to see how input travels through a computer and becomes output

Think of your keyboard and screen

⚡️ When you press a key on your keyboard, let's say the letter B, they keyboard converts that letter into a number. That number is sent as binary, ones and zeros, into the computer.

⚡️ With this number, the CPU calculates how to display the letter B pixel-by-pixel. The CPU requests step-by-step instructions from memory, which tell it how to draw the letter B.

⚡️ The CPU runs these instructions and stores the results as pixels in memory. Finally, this pixel information is sent in binary to the screen.

In this example, the input device is the keyboard and the output device is the screen, which converts the binary signals into the tiny lights and colors that make up what you see!

zerus and ona computer basics for kids

Story time:
The pixels painter

Two hundred. Blub! Thirty-two. Blub, blub, blub! Sixteen. Bluuuub!

"In, in, in! Put, put, puuut!" Ona hums, dragging her color cans.

"Ona, pixel 40, 128 still has no color! It's been waiting a while. Do you already know its input?" Zerus asks.

Ona looks around her cans. Some of them are red; others are green, and there are also blue! Some are completely filled with color, while others only have a bit of paint.

"Here it is, Zerus! Red, two hundred," she says, passing him the first can. "Green, thirty-two," she continues and gives him the second one, "and blue... sixteen!

Zerus begins to paint pixel 40, 128 when suddenly:

"Change of input, Zerus!" Ona exclaims. "The amount of blue is zero!"

"Ona, is this a human thing, to change their minds at the last minute?" Zerus looks confused. "It adds complexity to our tasks!"

Play time

Now, it's time for some games!

In this video, you'll take some paint as input and generate as many color mixes as you can think of (also known as output!). 🎨

⚡️ Watch this video in Spanish »

Download the material, get out your brushes, and let's get painting!

⚡ Download this game's material »

Horray-bits, Human! You just read a story about a pixels painter, learned about input and output, and did some color mixing.

Remember, understanding computers is a SUPERPOWER. So, keep on learning (and playing!). 💫

Lots of Megas from the Binary World,
Zerus & Ona

PS. We love to see what you create! Tag us on social @zerusandona and use the hashtag #ABCofComputers

About this episode

🎥 Video by Elena Escudier
🎨 Words and pictures by Miriam Tocino
🎶 Music by Felipe Ignacio Noriega
1️⃣ Keyboard example by Khan Academy

Keep learning

In the last episode of the ABC of Computers, humans learned about coding. They wrote a program to help a special computer build their favorite animal.

⚡ Read the episode about coding »