So base on different machine/computer architecture, there are following Instruction Set we need to learn. Thanks to John  von Neumann, I guess the types of machines is actually reduced by him.

IA-64 (Itanium)

MIPS

IBM 700/7000 series

–System/390

–z/Architecture

Power Architecture

–POWER

–PowerPC

SPARC

x86

–IA-32 (i386, Pentium, Athlon)

–x86-64 (64-bit superset of IA-32)