FIDE 2's research addresses the current critical situation in the construction, maintenance and operation of persistent application systems (PASs). The objective is to formulate a consistent framework for the support of the PAS construction and maintenance process, populate this with a consistent set of concepts, and show that this combination is not only sufficient for the construction and maintenance of PASs but also enables significant economies in their software construction and operation and permits the construction of more sophisticated PASs. FIDE 2 aims to encompass a wider range of the construction and operation activities than have been integrated hitherto and issues arising from longer-lived, larger-scale and more distributed systems than were considered in FIDE 1.
This objective will be met in three stages: 1) via a thorough analysis of the construction process of PASs and of the contributing concepts, technologies and components, and via a formulation of a consistent model for such applications, so that they may be constructed in the context of a much simpler, more coherent environment; 2) provide demonstrable prototype database programming language environments, database system environments and a prototype PAS workbench; 3) use these prototypes to demonstrate that a consistent and coherent Fully Integrated Data Environment (FIDE) can be achieved through technology and concepts integration, and that it yields a quantum leap in the productivity of PAS software engineers.
Within the programming language environment theme, important research topics were:
type systems (foundations, algorithms, dependent types, late binding overloading, schema evolution and dynamic abstract witness types);
bulk data types (how to provide bulk types, notations for query languages and structuring of libraries);
language design studies (on more expressive data modelling mechanisms, modularization and program composition mechanisms, and concurrency and transactions).
The database system environments work has concentrated on the comparison of the different persistent higher order abstract machines (PHOLAM) used to implement the various formally integrated data environment (FIDE) languages and the prototyping of object stores architectures to explore areas such as performance, distribution and scalability.
The persistent application systems (PAS) workbench strand has included the development of prototype workbench components and experiments in interoperability.
At the first review of the project in September 1993 a number of prototypes were demonstrated. These were concerned with language development (Fibonacci); optimization strategies and interoperability in the Tycoon environment; 2 different object store developments; and 3 prototype workbench components: a hyperprogramming environment, a graphical interface for constructing Napier88 programs and a reusable component retrieval system.
APPROACH AND METHODS
The FIDE 2 approach depends on the development of clearly specified concepts. These will be verified via discussion among the partners and via incorporation into experimental systems. These systems comprise database and persistent languages, persistent object stores and tool sets that enable their use. The consortium considers it essential to test the concepts in order to demonstrate that they are comprehensible to system builders and feasible to the engineer. All work in progress and final results are being published in the FIDE Research Report series, and the results will appear in the research literature.
In the short term, the primary influence of FIDE 2 will be on other research groups, who are expected to adopt its concepts and architectures in their explorations of extensions to database capabilities, programming language functionality and support system architectures. In the medium term, it will influence the development of widely used languages and the burgeoning research into persistent systems. Ultimately it will lead to new support system architectures modifying or replacing the operating systems of today. As the consistent and systematic semantics of concepts developed by FIDE 2 for building and managing long-lived systems gain adherence, the efficiency and achievements of the European software industry should be improved.
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