The Central Processing Unit (CPU) is the core of a computer, responsible for interpreting instructions and performing basic tasks like arithmetic, logic, control, and input/output. The term has been widely used since the 1960s.

A CPU is made up of four main components:

• Control Unit (CU): Directs data and instruction flow.

• Arithmetic Logic Unit (ALU): Handles calculations and logical operations.

• Registers: Ultra-fast memory for temporary data storage.

• Cache: Small, high-speed memory that reduces access to main memory.

These parts are synchronized by the clock rate and connected via three buses: data bus (carries data), address bus (memory locations), and control bus (manages I/O and other components).

CPU design depends on its instruction set architecture:

• CISC (Complex Instruction Set Computer): Executes multiple low-level tasks in several cycles.

• RISC (Reduced Instruction Set Computer): Focuses on simple instructions, each completed in a single cycle.