Hi,

Thanks! From what I read so far it sounds like my idea is called "Time Warp" / "Virtual Time".

On page 10 and 11 there is the notion of "Total Ordering": "The main problem in totally ordering events is that two or more events at different processes may have identical timestamp." - "A tie-breaking mechanism is needed to order such events." - "Process identifiers are linearly ordered and tie among events with identical scalar timestamp is broken on the basis of their process identifiers." This is what I meant with "+ clusterNodeId"

Vector time and Matrix time: I think it would need too much memory - if the dimension of vector clocks is the number of cluster nodes, then the number of dimensions would change whenever you add a cluster node.

Time Warp matches my suggestion: Page 33 says "Time Warp relies on the general lookahead-rollback mechanism where each process executes without regard to other processes having synchronization conflicts." - it sounds like my proposal (I specially like the term "Time Warp"). "If a conflict is discovered, the offending processes are rolled back to the time just before the conflict and executed forward along the revised path." "Virtual time is implemented a collection of several loosely synchronized local virtual clocks."

Regards, Thomas