The Delta-4 Extra performance architecture (XPA)

P. Barrett, P. Bond, A. Hilborne, L. Rodrigues, D. Seaton, N. Speirs, and P. Veríssimo

From the Digest of Papers, The 20th International Symposium on Fault-Tolerant Computing, Newcastle-UK, June 1990.


As part of the European Strategic Programme for Research in Information Technology (ESPRIT), the Delta-4 Project is seeking to define an open, fault-tolerant, distributed computing architecture. The Delta-4 approach to fault-tolerance is based upon the replication of software components on distinct host computers using a range of different replication strategies.

This paper presents the design of an Extra Performance Architecture for Delta-4 which explicitly supports the requirements of real-time systems with respect to throughput and response. The problems of replicate divergence are discussed, and a solution based on message selection and pre-emption synchronization messages is proposed. The paper includes a description of the on-going implementation of such system within the overall Delta-4 framework.

Not available in postscript.

Luís Rodrigues