Phase 0: How Computers Actually Work · ~35 minutes · Python · uv

What a Computer Actually Does

A computer never understands what you meant. It only ever does exactly what you said.

Hiring signal: Correctly distinguishes 'the computer is confused' from 'I gave it a precise, wrong instruction' — the mental model everything else in this course builds on

What you will learn

Explain what a bit and a byte are, and what it means for a program to be 'instructions plus data'
Describe the difference between RAM (memory) and disk (storage) in terms of what survives a restart
Trace the fetch-execute cycle at a level that explains why a computer can only do one precise thing at a time
Run a Python script and correctly predict the output of a second one before running it

Introduction

Type: Learn Languages: Python Prerequisites: None — true zero background Time: ~35 minutes

Learning Objectives

Explain what a bit and a byte are, and what it means for a program to be "instructions plus data"
Describe the difference between RAM and disk in terms of what survives a restart
Trace the fetch-execute cycle at a level that explains why a computer only ever does one precise thing at a time
Correctly predict the output of a small Python script before running it

Unlock the full lesson

You've read the first 2 sections. The rest of this lesson covers The Problem, Bits: the only thing a computer can actually store, Memory vs. storage: what survives a restart, A program is instructions, executed one at a time, on data, What This Means for Reading Error Messages, What You're Building, Key Terms, Exercises — plus a hands-on lab, quiz, and project artifact.

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