Computer architecture basics — terminology clarification: Which hardware device, in general terms, is capable of fetching, decoding, and executing a sequence of instructions issued by software?

Introduction / Context:
In computer architecture, several closely related terms describe parts of the execution engine. Learners often mix up CPU, processor, ALU, and control unit. This question checks whether you can pick the most precise, general term for a hardware device that executes a sequence of instructions.

Given Data / Assumptions:

• The device must be able to fetch, decode, and execute instructions.
• We are not limiting ourselves to a specific form factor (microprocessor, multi core SoC, or CPU package).
• Execution implies arithmetic, logic, control flow, and interaction with memory.

Concept / Approach:

The broadest correct label for any hardware entity that performs the instruction cycle (fetch, decode, execute, write back) is processor. The CPU (central processing unit) is a common subtype of processor. Internal subcomponents such as the ALU (arithmetic logic unit) and CU (control unit) participate but cannot execute full instruction sequences independently in general; they are functional blocks within a processor or CPU.

Step-by-Step Solution:

Verification / Alternative check:

Architecture texts define a processor as the hardware that executes machine instructions. A CPU is a central processor in a traditional architecture; GPUs and NPUs are also processors because they execute instruction streams, reinforcing that “processor” is the most general fit.

Why Other Options Are Wrong:

• CPU: often correct, but it is a specific class of processor; the question asks for the general term.
• ALU: performs arithmetic and logic, not full instruction sequencing.
• CU: coordinates operations but does not by itself execute full instruction sets.
• None of the above: incorrect because “Processor” fits perfectly.

Common Pitfalls:

Equating “CPU” with every processor; forgetting that modern systems include multiple specialized processors. Also, confusing subunits (ALU, CU) with the complete execution engine.

Final Answer:

Processor