Computer Architecture & How a Computer Actually Works

🔷 Big Picture

Today you learn how everything from the last three days — electricity, heat, transistors, logic — becomes a full working computer.

Computer architecture = the design of how the CPU, memory, storage, buses, and devices all work together to run programs.

🧠 The Four Pillars of Computer Architecture

1. CPU (Central Processing Unit)

The “brain” of the computer — performs operations and follows instructions.

Major CPU parts:

• ALU (Arithmetic Logic Unit):

  Performs math and logic (add, subtract, AND, OR, compare)

• Control Unit:

  Directs the flow of instructions

• Registers:

  Ultra-fast storage inside the CPU

• Cache:

  High-speed memory the CPU uses to avoid waiting on RAM

2. Memory (RAM)

Temporary storage that holds:

• The program you’re running
• The data the CPU is currently using
• Variables, instructions, and temporary results