V: The V distributed system was developed at Stanford University as part of a research project to explore communication issues in distributed systems. The pro- cess group abstraction was introduced there to encapsulate distribution (Cheriton and Zwaenepoel 1985).
Amoeba: The Amoeba microkernel-based distributed operating system was devel- oped at the Vrije University of Amsterdam to devise applications on a collection of workstations or single board computers (Kaashoek et al. 1989).
Delta-4: The Delta-4 project was a European research project under the ESPRIT Programme that defined an architecture to build dependable system based on reliable (group) communication abstractions. Many of the ideas underlying Delta- 4 were later incorporated in the FT-CORBA standard (Powell 1991, 1994).
Replicated RPC: Circus was one of the first systems to use the group com- munication abstraction to access replicated servers. It included a replicated remote-procedure call facility implemented in Berkeley Unix (Cooper 1984a,b