Endianness facts for kids

Endianness is a fancy word that describes how computers store numbers, especially when those numbers are made of several parts. Think of it like putting together a LEGO brick with multiple pieces. Do you put the biggest piece first, or the smallest?

In computer programming, numbers are often stored in chunks called "bytes." A byte is a small piece of information, like a single letter or a small number. When you have a bigger number, it might take up two or more bytes. These groups of bytes are sometimes called "words."

There are two main ways a computer can arrange these bytes:

• Big-endian: The biggest, most important part of the number comes first.
• Little-endian: The smallest, least important part of the number comes first.

It's like writing a date: in some countries, you write Month-Day-Year (like 04/21/2024), and in others, you write Day-Month-Year (like 21/04/2024). Both are correct, but they arrange the information differently.

Understanding Big-Endian and Little-Endian

Let's look at an example using a number that's two bytes long. Computers often use a number system called hexadecimal, which uses digits 0-9 and letters A-F.

Imagine we have the hexadecimal number 12AB. This number is made of two bytes: "12" and "AB".

Big-Endian Order

In a big-endian system, the computer stores the bytes in the order you'd normally read them: the most significant (biggest) byte first, then the least significant (smallest) byte.

So, for 12AB, it would be stored as:

• 12 (first byte)
• AB (second byte)

This is like writing a number from left to right, with the hundreds or thousands place first.

Little-Endian Order

In a little-endian system, the computer stores the bytes in the opposite order: the least significant (smallest) byte first, then the most significant (biggest) byte.

So, for 12AB, it would be stored as:

• AB (first byte)
• 12 (second byte)

It might seem a bit backwards, but many computers, like those using Intel processors, use little-endian.

Why Does Endianness Matter?

Endianness is important when computers need to share information. If one computer sends data in big-endian format and another expects it in little-endian, they won't understand each other! It's like trying to read a book that's written from right to left when you're used to reading left to right.

Programmers and computer engineers need to know about endianness to make sure different devices and programs can talk to each other correctly. This is especially true for things like:

• Networking: When computers send data over the internet.
• File Formats: How data is saved in files, like images or music.
• Hardware: How different parts of a computer communicate.

Origin of the Term

The words "big-endian" and "little-endian" come from a famous book called Gulliver's Travels, written by Jonathan Swift in 1726.

In the story, there are tiny people called Lilliputians. They have a big argument about the best way to crack a boiled egg. Some believe you should always crack it from the big end (the "Big-Endians"), while others insist on cracking it from the little end (the "Little-Endians"). This silly argument leads to a war!

Computer scientists borrowed these terms to describe the equally important, but less violent, "wars" over how to store data in computers.

Images for kids

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  The adjective endian comes from the 1726 novel Gulliver's Travels by Jonathan Swift where characters known as Lilliputians are divided into those breaking the shell of a boiled egg from the big end (Big-Endians) or from the little end (Little-Endians)