What is the meaning of internel part of CPU?

Answer 1

The CPU, Central Processing Unit, is typically constructed of several parts:

(1) a register set or "file" where addresses can be computed and results stored,

(2) the ALU or Arithmetic Logic Unit which performs the addition, subtraction, shifting, inverting, anding, etc.

(3) for CISC architectures, the microcode sequencer (RISC architectures use instruction decoders)

(4) interrupt hardware

(5) MMU or Memory Management Unit, typically found in processors that support Linux and other OSs

(6) clock management and other internal connection circuitry