We consider the problem of developing reliable applications to be deployed
in partitionable asynchronous distributed systems. What makes this task dif
ficult is guaranteeing the consistency of shared state despite asynchrony,
failures and recoveries, including the formation and merging of partitions.
While view synchrony within process groups is a powerful paradigm that can
significantly simplify reasoning about asynchrony and failures, it is insu
fficient for coping with recoveries and merging of partitions after repairs
. We first give an abstract characterization for shared state management in
partitionable asynchronous distributed systems and then show how views can
be enriched to convey structural and historical information relevant to th
e group's activity. The resulting paradigm, called enriched view synchrony,
can be implemented efficiently and leads to a simple programming methodolo
gy for solving shared state management in the presence of partitions.