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This atlas is read as a build queue, not a course catalog. Each branch is a real program; you finish one before the next one needs it.

Before you start

Do Low-Level Atlas I first, completely — at minimum its machine model, C from the metal, pointers & memory, and systems programming branches. Nothing here re-teaches what a syscall, a stack frame, or fork() is.

The build queue

1. Warm up. Shell from Scratch, malloc from Scratch, and Regex Engine from Scratch — short, self-contained, one to two weeks each. Pick any order.
2. Build something with state. Mini Git — content-addressed storage, a result you'll actually keep using.
3. Talk to the network. HTTP Server from Scratch — the shortest of the project branches, the on-ramp to everything that follows.
4. Make it concurrent. Start Concurrency in Practice alongside the HTTP server — don't wait until it's "done."
5. Build the spine. KV Store & Durability (v0 → v1), then Relational Layer & Query Engine (v2 → v3) — the project that consumes everything else.
6. Never stop testing it. Craftsmanship Low-Level II runs alongside every branch above, not after them.

How to read it

• Every branch is a real, runnable program — not a set of notes about a program. The deliverable is code that builds and runs, same bar as Atlas I's examples.
• Concurrency is not a separate phase you do once. It's threaded through the network and database phases on purpose.
• The database engine is versioned (v0 → v3) the same way Atlas I's OS was built in milestones — read the roadmap on the home page before diving in.

See also: Must Know · Full Index