Editing Distributed shared memory (section)

== Consistency models ==
The DSM must follow certain rules to maintain consistency over how read and write order is viewed among nodes, called the system's ''[[consistency model]]''.

Suppose we have ''n'' processes and ''Mi'' memory operations for each process ''i'', and that all the operations are executed sequentially. We can conclude that (''M1'' + ''M2'' + ... + ''Mn'')!/(''M1''! ''M2''!... ''Mn''!) are possible interleavings of the operations. The issue with this conclusion is determining the correctness of the interleaved operations. Memory coherence for DSM defines which interleavings are permitted.

[[File:Sequential invocations and responses in DSM.jpg|380px|right|Sequential invocations and responses in DSM]]