The author mentions in passing "Virtual Synchrony" . It turns out it is used in some highly critical systems via ISIS/VSync framework from Cornel:
The "CORBA Fault Tolerant Objects standard" is based on the virtual synchrony model. Virtual synchrony was also used in developing the New York Stock Exchange fault-tolerance architecture, the French Air Traffic Control System, the US Navy AEGIS system, IBM's Business Process replication architecture for WebSphere and Microsoft's Windows Clustering architecture for Windows Longhorn enterprise servers.
The "CORBA Fault Tolerant Objects standard" is based on the virtual synchrony model. Virtual synchrony was also used in developing the New York Stock Exchange fault-tolerance architecture, the French Air Traffic Control System, the US Navy AEGIS system, IBM's Business Process replication architecture for WebSphere and Microsoft's Windows Clustering architecture for Windows Longhorn enterprise servers.
https://en.wikipedia.org/wiki/Virtual_synchrony#Virtual_sync...
https://en.wikipedia.org/wiki/Vsync_(computing)