Editing Regular semantics (section)

== Example ==

Regular semantics are weaker than [[linearizability]]. 
Consider the example shown below, where the horizontal axis represents time, and the arrows represent the interval during which a read or write operation takes place.  According to a regular register's definition, the first read may return 5 or 2, and so may the second read. The first read could return 2 and the second read could return 5 (also known as a new/old inversion). This behavior would not satisfy [[atomic semantics]]. Therefore, regular semantics is a weaker property than atomic semantics. On the other hand, [[Leslie Lamport]] proved that a linearizable register may be implemented from registers with [[safe semantics]], which are weaker than regular registers.<ref>{{cite journal |last1=Lamport |first1=Leslie |title=On interprocess communication - Part I: Basic formalism |year=1986 |journal=Distributed Computing |volume=1 |issue=2 |pages=86–101 |publisher=Springer-Verlag |doi=10.1007/BF01786228 |url=https://link.springer.com/article/10.1007/BF01786228}}</ref>

[[File:Regular-but-not-linearizable.png|centre|Regular Register]]