Which of the following is not a function of the control unit?

The correct answer is Executing instructions.

Key Points

• The control unit (CU) is a component of a computer's central processing unit (CPU) that directs the operation of the processor.
• The CU reads and interprets instructions from the computer's memory.
• It directs the operation of the other units by providing timing and control signals.
• Executing instructions is the function of the Arithmetic Logic Unit (ALU) and not the control unit.
• The CU does not execute instructions; it only fetches and decodes them.

Additional Information

• Central Processing Unit (CPU)
  • It is the primary component of a computer that performs most of the processing inside a computer.
  • The CPU is composed of the Arithmetic Logic Unit (ALU) and the Control Unit (CU).
  • The CPU performs basic arithmetic, logic, controlling, and input/output (I/O) operations specified by the instructions in the program.
• Arithmetic Logic Unit (ALU)
  • The ALU is a digital circuit used to perform arithmetic and logic operations.
  • It is a fundamental building block of the CPU of a computer.
  • The ALU performs all arithmetic and logical operations, such as addition, subtraction, and comparison.
• Instruction Cycle
  • The instruction cycle is the process by which a computer retrieves a program instruction from its memory, determines what actions the instruction requires, and carries out those actions.
  • This cycle is repeated continuously by the CPU from boot-up to when the computer is shut down.
• Fetch-Decode-Execute Cycle
  • This is the basic operation cycle of a computer.
  • During the fetch step, the CU retrieves an instruction from memory.
  • In the decode step, the CU interprets the instruction.
  • In the execute step, the ALU performs the operation specified by the instruction.