The Parable of Big-Endian and Little-Endian

The terms “big-endian” and “little-endian” come from Jonathan Swift’s Gulliver’s Travels, where two fictional kingdoms went to war over which end of a boiled egg should be opened first. Computer engineers, finding this satirical commentary on human pettiness to be mirrored in the constant byte-bickering of the 70s and 80s, decided to apply the same principle.

The Two Schools of Thought

Big-Endian (also called “network byte order”):

• Most significant byte comes first
• Reads naturally from left to right (for humans accustomed to Western number systems)
• Used by network protocols, Java Virtual Machine, and certain RISC processors

Little-Endian:

• Least significant byte comes first
• Reads backwards (from a human perspective)
• Used by Intel x86/x64, most ARM processors, and assorted rebels

A Concrete Example

Consider the 32-bit hexadecimal number 0x12345678. How would different systems store this in memory?

lfe> (set num #x12345678)
305419896

; Big-endian representation (most significant byte first):
lfe> (binary ((num (size 32) big)))
#B(18 52 86 120)  ; 0x12, 0x34, 0x56, 0x78

; Little-endian representation (least significant byte first):
lfe> (binary ((num (size 32) little)))
#B(120 86 52 18)  ; 0x78, 0x56, 0x34, 0x12

Notice how the bytes are in completely opposite order. This is why cross-platform binary protocols require careful specification of byte order—what looks like 0x12345678 on one system might be interpreted as 0x78563412 on another.