Endianness

When a value uses more than one byte, like a 16-bit number (2 bytes), the order of those bytes can vary depending on the system:

• Big-endian: Most significant byte first (e.g. 0x12 0x34)
• Little-endian: Least significant byte first (e.g. 0x34 0x12)

This creates problems when you move files between systems with different architectures. For example, Windows is little-endian, but network protocols are big-endian.