Linked from
The 29 pages that link to Machine code, each with the reason it gives.
Instruction set architectureRelated: An ISA specifies how instruction bit patterns are interpreted.
Stored-program computerRelated: Stored programs ultimately consist of machine-code instructions.
MicrocontrollerRelated: A microcontroller ultimately runs firmware as machine-code instructions.
Altair 8800Related: The Altair’s switches made machine-code entry unusually visible and hands-on.
HexadecimalRelated: Disassemblers often show instruction bytes in hexadecimal.
ExecutableRelated: Machine code is the executable's processor-specific instruction content.