Which of the following is not typically considered part of a CPU?

• A. Alu
• B. Registers
• C. Control Unit
• D. Disk Drive

Answer: (D)

The essential idea is which pieces are built into the central processing unit versus part of other computer subsystems. Inside the CPU you’ll find the ALU, which performs arithmetic and logic operations; registers, which hold data and instructions for quick access during processing; and the control unit, which decodes instructions and coordinates the flow of data between the CPU’s parts. A disk drive, in contrast, is part of the storage or I/O subsystem. It provides long-term data storage and is accessed via controllers and the memory hierarchy, not directly by the CPU’s internal processing core. The CPU may fetch data that eventually came from storage, but the disk drive itself isn’t considered a CPU component.