The internal structure of the computer contains four main structural components. They are,
Central processing unit (CPU): Controls the operation of the computer and performs its data processing functions; often simply referred to as processor.
Main memory: Stores data.
I/O: Moves data between the computer and its external environment.
System interconnection: Some mechanism that provides for communication among CPU, main memory, and I/O.
And the major structural components of CPU are,
Control unit: Controls the operation of the CPU and hence the computer.
Arithmetic and logic unit (ALU): Performs the computer’s data processing functions.
Registers: Provides storage internal to the CPU.
CPU interconnection: Some mechanism that provides for communication among the control unit, ALU, and registers.