Per Sandén (2011), in a distributed system nodes can talk (cooperate) to each other and coordinate their systems. However, the different nodes can execute concurrently, there is no global clock in which all nodes function on, and some of these nodes can fail independently. Since nodes talk to each other, we must study them as they interact with each other. Thus, there is a need to use logical clocks (because we don’t have global clocks) which show that distances in time that is lost.
In logical clocks: all nodes agree on an order of events, partially (where something can happen before another event). They only describe the order of events, not with respect to time. If nodes are completely disjoint in a logical clock, then a node can fail independently.
- Sandén, B. I. (2011-01-14). Design of Multithreaded Software: The Entity-Life Modeling Approach, 1st Edition. [VitalSource Bookshelf Online]. Retrieved from https://bookshelf.vitalsource.com/#/books/9781119143086/