little endian / big endian

we write dates in two main orders

1. 2023-03-17 (“big endian”)
2. 17-03-2023 (“little endian”)
3. 03-17-2023 (“american”)

“big endian” means that the big unit (the year) is at the start (“big end first”)

similarly: computers order bytes in 2 ways

Here are 2 ways your computer might represent the integer 271: 1. big endian: 00000001 00001111 2. little endian: 00001111 00000001

How this corresponds to 271:

00000001 00001111 is 271 in binary

When you send integers on a computer network, they have to be big endian. Here’s how that works:

Computer A has the 16-bit integer “271” in its memory: 00001111 00000001

Computer A flips the bytes and sends it as big endian: 00000001 00001111

Computer B receives the big endian integer

Computer B flips the bytes and stores it in memory as little endian: 00001111 00000001

a little history

Before 1980, computers ordered their bytes in different ways.

In 1980, the Internet started being standardized, causing a huge fight over which byte order to use on the Internet.

The terms “big/little endian” come from that fight: they were coined in an article called “On Holy Wars and a Plea For Peace” which compares the byte order fight to the Big/Little Endians in Gulliver’s Travels.

Big endian won that fight, so most Internet protocols (IPv4, TCP, UDP, etc.) are big endian.

But almost all modern computers are little endian. Some machines, like the Xbox 360, are big endian though.