Distributed Systems, Consistency.
gives Linearizability. Example 1: In Example1 R should always read 2. Example 2: In Example 2 R is overlapping with w1 and w2 hence it could be put in any of the slots between w(1) and w(2) _ W(1) _ W(2) _ R W(1) _ W(2) _ _ W(1) R W(2) _ _ W(1) _ W(2) R So it can return 1 or 2 Sequential