Programming distributed systems with Group_IO

This paper describes Group_IO, a software library written in Ada which facilitates the construction of distributed applications by means of the group paradigm, an abstraction which considers a set of processes as an individual entity. Group_IO provides support for replicated as well as cooperative groups. Group_IO offers a straightforward interface to reliable, atomic, causal, and uniform multicast services, and it allows client-server interactions where the client may be a process group. It relies on an own consensus protocol to implement the uniform broadcast protocols. Group_IO provides support for the client/server group (1-to-M) communication, client group/server (N-to-1) and client group/group server (N-to-M) communication. Group_IO is the basis on which the programming language Drago has been implemented.