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The Symposium on Foundations in Software Engineering is an annual conference sponsored by Association for Computing Machinery, a computer portal and dedicated to the presentation of innovative research results contributing to an engineering discipline for software systems. This special section of the July 1998 issue of the journal IEEE Transactions on Software Engineering features three of the best papers from the fourth symposium, held in October 1996 in San Francisco, California. During its first half-decade, research results presented at this conference have covered engineering research topics. However, a number of distinguishing properties tend to characterize the best of the papers and have helped set the standards for high-quality software engineering research. The three papers in this special section illustrate these properties. One of the critical challenges for software engineering research is to find practical tools that help system builder restructure existing systems. Mark Moriconi was general chair for the symposium and deserves considerable credit for its success.

SDD-1, A System for Distributed Databases, is a distributed database system being developed by Computer Corporation of America (CCA), Cambridge, MA. SDD-1 permits data to be stored redundantly at several database sites in order to enhance the reliability and responsiveness of the system and to facilitate upward scaling of system capacity. This paper describes the method used by SDD-1 for updating data that are stored redundantly. Redundant updating can be costly because it may potentially involve extensive intercomputer communication overhead in order to lock all copies of data being updated. The method described here avoids this overhead by identifying cases in which it is not necessary to perform this global database locking. The identification of transactions that do not require global locking is based on a predefinition of transaction classes performed by the database administrator using an analysis technique described herein. The classes defined are used at run time to decide what level of synchronization is needed for a given transaction. It is important to note that this predefinition activity in no way limits the transactions that the system can accept; it merely permits more efficient execution of those types of transactions that were anticipated. [ABSTRACT FROM AUTHOR]