Research can rarely be performed on large-scale, distributed systems at the level of thousands of workstations. In this paper, we describe the motivating constraints, design principles, and architecture for an extensible, distributed system operating in such an environment. The constraints include continuous operation, dynamic system evolution, and integration with extant systems. The Information Bus, our solution, is a novel synthesis of four design principles: core communication protocols have minimal semantics, objects are self-describing, types can be dynamically defined, and communication is anonymous. The current implementation provides both flexibility and high performance, and has been proven in several commercial environments, including integrated circuit fabrication plants and brokerage/trading floors.

In a database to which data is continually added, users may wish to issue a permanent query and be notified whenever data matches the query. If such continuous queries examine only single records, this can be implemented by examining each record as it arrives. This is very efficient because only the incoming record needs to be scanned. This simple approach does not work for queries involving joins or time. The Tapestry system allows users to issue such queries over a database of mail and bulletin board messages. The user issues a static query, such as “show me all messages that have been replied to by Jones,” as though the database were fixed and unchanging. Tapestry converts the query into an incremental query that efficiently finds new matches to the original query as new messages are added to the database. This paper describes the techniques used in Tapestry, which do not depend on triggers and thus be implemented on any commercial database that supports SQL. Although Tapestry is designed for filtering mail and news messages, its techniques are applicable to any append-only database.

Article Viewstamped Replication: A New Primary Copy Method to Support Highly-Available Distributed Systems Share on Authors: Brian M. Oki Massachusetts Institute of Technology, Laboratory for Computer Science, Cambridge, MA Massachusetts Institute of Technology, Laboratory for Computer Science, Cambridge, MAView Profile , Barbara H. Liskov Massachusetts Institute of Technology, Laboratory for Computer Science, Cambridge, MA Massachusetts Institute of Technology, Laboratory for Computer Science, Cambridge, MAView Profile Authors Info & Claims PODC '88: Proceedings of the seventh annual ACM Symposium on Principles of distributed computingJanuary 1988 Pages 8–17https://doi.org/10.1145/62546.62549Online:01 January 1988Publication History 163citation2,063DownloadsMetricsTotal Citations163Total Downloads2,063Last 12 Months112Last 6 weeks17 Get Citation AlertsNew Citation Alert added!This alert has been successfully added and will be sent to:You will be notified whenever a record that you have chosen has been cited.To manage your alert preferences, click on the button below.Manage my AlertsNew Citation Alert!Please log in to your account Save to BinderSave to BinderCreate a New BinderNameCancelCreateExport CitationPublisher SiteGet Access

Abstract : In designing fault-tolerant distributed database, a frequent goal is making the system highly available despite component failure. We examine software approaches to achieving high availability in the presence of partitions. In particular, we consider various replicated-data management protocols that maintain database consistency and attempt to increase database availability when networks partition. We conclude that no protocol does better than a bound we have determined. Our conclusions hold under the assumption. There may be some particular distribution for which specialized protocols can increase availability. (KR)