Lamport: Time Clock and the Ordering of Distributed Systems
Uses “happens before” - partial ordering of events
- Introduces a way to sync the total ordering
- provides for clocks, how to translate it to actual clocks
is time subjective? is it independent of observers?
is there a way to capture “happen before” without clocks?
- can we determine if a single event preceded another without the measurement of objective time?
- on differing nodes
- total ordering of events cannot be done, only partial ordering on specific nodes
- 1: a-b-c
- 2: x-y-z
- a comes before b and c, but a does not come before x, y, or z
- a and b are in the same process, and a comes before b, a happens before b
- if a sends a message and b receives it, a must happen before b
- if a -> t and t -> b then a -> b