Computer architecture basics: A system built from a microprocessor unit (MPU), a memory unit, and input/output (I/O) interfaces together forms which type of digital system?

Introduction / Context:
A complete computing system needs processing, storage, and I/O. Recognizing the minimal set of building blocks clarifies terminology used in embedded systems and classic computer architecture descriptions.

Given Data / Assumptions:

• Microprocessor unit (central processing chip).
• Memory unit (ROM/RAM/flash).
• Input/Output interfaces (ports, peripherals, buses).

Concept / Approach:
A central processing unit alone is not sufficient. When you add memory and I/O around a microprocessor, you obtain a complete microcomputer. The term CPU refers to the processing core; ALU is only the arithmetic-logic component within the CPU; a compiler is a software tool, not hardware.

Step-by-Step Solution:
Start with MPU: executes instructions.Add memory: stores program and data.Add I/O: enables interaction with external devices and users.These three together constitute a microcomputer.

Verification / Alternative check:
Block diagrams in textbooks show the microprocessor at the center with address/data/control buses connected to memory and I/O, labeled ”microcomputer system”.

Why Other Options Are Wrong:
CPU: only the processing core, not a full system.Compiler: software, not hardware architecture.ALU: a sub-block inside the CPU.

Common Pitfalls:
Using CPU and microprocessor interchangeably with microcomputer; the latter implies a complete, usable system.

Final Answer:
microcomputer