What a computer is
A computer stores everything as bits and is built from two-state switches.
topic 02
Base CS from zero
Start with no CS theory. Finish understanding how a computer runs your code and what every programming construct really means.
Memory
Memory is a long row of numbered cells; an address is the number, a value is what sits there.
The processor
The CPU repeats one loop forever: fetch an instruction, decode it, execute it.
From machine code to a language
High-level code is translated — compiled or interpreted — into the instructions the CPU runs.
- 1 The assembler idea
- 2 Why high-level languages
- 3 Compilation vs interpretation
- 4 The runtime
- 5 From source to running program
- 6 From machine code to a language: multiple-choice review
- 7 From machine code to a language: free-recall review
- 8 From machine code to a language: code and mapping reading
- 9 From machine code to a language: trace a program down the ladder
Values and types
Bits mean nothing alone; a type is the rule that says how to read them.
Variables and state
A variable is a named memory cell; assignment changes what it holds.
Control flow
Conditionals and loops are the CPU choosing which instruction to run next.
Functions and the call stack
Every call pushes a frame onto the stack; returning pops it back off.
- 1 What a function is
- 2 The call stack
- 3 Parameters and return values
- 4 Scope
- 5 Recursion preview
- 6 Functions and the call stack: multiple-choice review
- 7 Functions and the call stack: free-recall review
- 8 Functions and the call stack: code and trace reading
- 9 Functions and the call stack: build a stack tracer
Data in memory
Arrays are contiguous cells; objects are labelled cells — both are layouts in memory.
Abstraction
Bundling data with the operations on it lets you stop thinking about the machine.
When a program fails
An error is the machine reporting it cannot continue; the stack trace says where.
Time and concurrency
Async exists because the CPU must not sit idle while a slow device answers.
You can see the whole topic now.
Every unit, from the underground to the orbit. Base CS from zero is one constellation in the atlas — climb another topic and watch the next one light up.