fault-tolerance
4 free lessons tagged fault-tolerance across Science, Programming. Each one is a short sequence of focused steps with narration and a five-question quiz at the end — take them in any order, no signup required.
Quantum error correction: from noisy qubits to logical qubits
Why quantum errors are uniquely hard, how stabilizer codes detect them without destroying the data, what the surface code and code distance mean, and why crossing the threshold turned error correction from theory into the field's central engineering race.
Errors, syndromes, and the surface code
Why classical error correction does not directly transfer to qubits, how stabilizer codes and syndrome measurement work around the no-cloning constraint, the surface code as the leading approach, and the math of physical-to-logical qubit overhead.
Failure and Time in Distributed Systems
Distributed systems break in ways single machines don't: nodes crash silently, messages vanish, and clocks lie. Learn the standard failure taxonomy, why a global clock is physically impossible, and how Lamport and vector clocks let you reason about causality without one.
Consensus: Raft and Paxos
Consensus is the hardest fundamental problem in distributed systems — and the one everything else depends on. Understand why FLP makes it theoretically impossible in async systems, how quorums work, and exactly how Raft solves leader election, log replication, and commitment safely.