Concurrency control has been thoroughly studied in the context of traditional database applications such as banking and airline reservations systems. There are relatively few studies, however, that address the concurrency control issues of advanced database applications such as CAD/CAM and software development environments. The

The Inscape Environment is an integrated software development enviroment for building large software systems by large groups of developers. It provides tools that are knowledgeable about the process of system construction and evolution and that work in symbiosis with the system builders and evolvers. These tools are integrated around the constructive use of formal module interface specifications. We first discuss the problems that Inscape addresses, outline our research strategies and approaches to solving these problems, and summarize the contributions of the Inscape Environment. We then discuss the major aspects

Software engineering focuses on producing quality software products through quality processes. The attention to processes dates back to the early 70's, when software engineers realized that the desired qualities (such as reliability, efficiency, evolvability, ease of use, etc.) could only be injected in the products by following a disciplined flow of activities. Such a discipline would also make the production process more predictable and economical.

This chapter surveys extended transaction models proposed to support long duration, interactive and/or cooperative activities in the context of multi-user software development and CAD/CAM environments. Many of these are variants of the checkout model, which addresses the long duration and interactive nature of the activities supported by environments but still isolates environment users, making it difficult for them to collaborate while their activities are in progress. However, a few cooperative transaction models have been proposed to facilitate collaboration, usually while maintaining some guarantees of consistency.

Intellectual control over software development projects requires the existence of an integrated set of explicit models of the products to be developed, the processes used to develop them, the resources needed, and the productivity and quality aspects involved. In recent years the development of languages, methods and tools for modeling software processes, analyzing and enacting them has become a major emphasis of software engineering research. The majority of current process research concentrates on prescriptive modeling of small, completely formalizable processes and their execution entirely on computers. This research direction has produced process modeling languages suitable for machine rather than human consumption. The MVP project, launched at the University of Maryland and continued at Universitt Kaiserslautern, emphasizes building descriptive models of large, real-world processes and their use by humans and computers for the purpose of understanding, analyzing, guiding and improving software development projects. The language MVP-L has been developed with these purposes in mind. In this paper, we motivate the need for MVP-L, introduce the prototype language, and demonstrate its uses. We assume that further improvements to our language will be triggered by lessons learned from applications and experiments.

The database community has produced extensive research on the concurrency control problem in the context of traditional databases. However, this traditional model is not suitable for some applications, such as software development environments and cad/cam systems. What is needed is an extended transaction model better suited for these newer applications. Unfortunately, there is no consensus as to which of the almost dozens of extended transaction models is appropriate. This paper posits that there is no single model which will be applicable to every application and seeks other ways to use existing database technology. Towards this end, we present Pern, a new transaction manager component which provides the flexible and tailorable support required by advanced database applications. 1 Introduction Software development environments (SDEs) have evolved to meet the ever increasing complexity of managing the development of software systems. As SDE researchers focus their attention on larg...

The Inscape Environment research project addresses issues in supporting the development of large systems by large numbers of programmers. One aspect of this research is the "constructive use" of formal module interface specifications - that is, given that you have formal specifications, what can you do with them. In Inscape, the specifications form the basis for providing an environment that is knowledgeable about the process of developing and evolving software systems, an environment that works in symbiosis with the programmer to develop and evolve a software system. In this discussion, I present how Inscape uses operation specifications (based on Hoare's input/output predicate approach) as the basis for synthesizing the interfaces for such complex languages statements as sequence, selection and iteration. In each of these statements, the synthesized interface is a function of the component interfaces. I first present the basic rules for interface specification use and the logical fra...

this paper is to present a novel approach to integration test management suitable for largescale projects. Our approach has four primary contributions: hierarchical integration, semi-automatic construction of test harnesses, semi-automatic construction of regression test suites, and integration of these facilities into Infuse, an experimental software development environment.

rnal Concurrency Control (ECC) architecture that captures the essence of advanced database applications. We show how a transaction manager can employ semantic information from the Task Management Layer (TML) of these applications. Our mediator-based architecture allows for flexible integration of a transaction manager component with advanced database applications and provides for generic extraction of semantic information from database applications. The Pern transaction manager component we implemented realizes the ECC architecture. Pern employs a declarative concurrency control language, called Cord that determines how to extend the behavior of transactions. Using Cord, an ETM is specified by its extensions to serializability. Pern can then support the desired ETM by applying Cord rules during transaction execution. Cord is practical since it assumes that the transaction

Introduction Developers frequently confront a dilemma that may be characterized by the following: 90% of the functionality requested by our customer is available in an existing off-the-shelf application, but the missing 10% is vital to the customer. Unfortunately, we cannot customize or adapt the existing application to meet our customer's needs--we have no choice but to buid a custom solution from scratch." As a result, a relatively small change in functionality necessitates a disproportionately large amount of effort, and curtails the opportunity for software reuse. This undesirable outcome may have been avoided if the off-the-shelf application supported decentralized software evolution, which we define as the ability to evolve software independent of the original software vendor. Decentralized software evolution (hereafter abbreviated DSE) provides a means for third-party software vendors to customize existing applications for particular domains and customers. This capabili