Arithmetic Logic Unit (ALU) & Storage Unit in CPU – Basic 3 Computer Studies Lesson Note (Second Term)

Review of CPU Parts

Let’s learn more about the important parts inside the CPU brain.

Arithmetic Logic Unit (ALU)

• Arithmetic part does math:
  1. Addition (2 + 3 = 5)
  2. Subtraction (7 – 4 = 3)
  3. Multiplication (3 × 2 = 6)
  4. Division (8 ÷ 2 = 4)
• Logic part makes decisions:
  1. Is 5 greater than 3? (YES)
  2. Are these numbers equal? (NO)
  3. Which number is smaller?

Storage Unit

Types of Storage in CPU:

• Registers – super fast, tiny storage
• Cache memory – fast storage for frequent data
• Primary memory – temporary storage while working

What Storage Unit Does:

• Keeps numbers while ALU calculates
• Stores instructions waiting to be done
• Holds results before sending them out
• Like a desk where you keep your work

Exercise 2: Complete these:

1. ALU does _______ and makes _______
2. Storage unit is like a _______ where you keep work
3. Which is faster: registers or cache? _______