Distributed systems · 1978 · Leslie Lamport
Time, Clocks, and the Ordering of Events in a Distributed System
Derive distributed time from potential causation: happened-before defines a partial order and logical clocks extend it without creating a shared physical clock.
The central move
Derive distributed time from potential causation: happened-before defines a partial order and logical clocks extend it without creating a shared physical clock.
Why it had to exist
Independent machines observe different times, messages take variable paths, and no observer sees all events. Wall-clock timestamps alone cannot say what may have caused what.
Where it leads
Causal order → logical and vector clocks → replication, event logs, consistency, and distributed debugging.