fault-tolerance

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.

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 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.