Group orientation: a paradigm for modern distributed systems
Paulo Veríssimo and Luís Rodrigues
This paper is an extended and revised version of a paper appeared in
Proceedings of the ACM SIGOPS 1992 Workshop, Mont Saint-Michel, France.
Increasing use of distributed systems, with the corresponding
decentralisation, stimulates the need for structuring activities
around groups of participants, for reasons of consistency,
user-friendliness, performance and dependability. Although there is a
significant number of group communication protocols in the literature,
they are penetrating too slowly in operating systems technology. Two
important reasons are: the literal interpretation generally made of
the end-to-end argument, and the lack of a layer mapping end-user
needs (management of replication, competition, cooperation and group
membership) into what is generally provided by the communication
layer: agreement and order properties.
The paper discusses both problems, proposing ways for structuring
systems and defining building blocks for group-oriented activity,
using concepts like object groups. It suggests that the group concept
should pervade the whole architecture, from network multicasting, to
group communications and management. Emerging technology will help
materialise these concepts.
Also available as
INESC AR/64-92 (gzip postscript).