The link you give defines isolation like this: "The isolation property ensures that the concurrent execution of transactions results in a system state that would be obtained if transactions were executed serially, i.e., one after the other."

That sounds awfully close to the definition of serializability he's using.

Agreed.

Also, Microsoft SQL Server does support snapshot isolation. See: https://msdn.microsoft.com/en-us/library/tcbchxcb(v=vs.110)....

But not for indexes...