. Research into persistent programming languages and systems in recent years has shown that the technology is useful for developing complex software in many problem domains. This paper explores the issues and consequences of adding persistence to Ada95. The persistence extensions support transparent migration of objects between a program's address space and a persistent store in a way that preserves both type safety and encapsulation of abstract data types. 1 Introduction Ada has recently undergone a major cycle of review and update. The result of this is the new programming language Ada95[12] which is, in the main, backward compatible with Ada83[18]. Two of the principle changes to Ada were the addition of constructs to make it a fully fledged object-oriented language and the use of annexes for defining specialist language capabilities. This paper examines the emerging technology of persistence, and considers how persistent programming can be supported in Ada. We start by introducing...

Saving internal program data for further use is one of the most useful ideas in programming. Developing general features to provide such data saving/ restoring is a very active research area. There are two application areas for such features we believe to be crucial: system fault tolerance and data persistence. Our analysis shows that the features used in these areas have a lot in common: they are to flatten data of different types and save them in a store which can be used later on. The recent revision of the Ada language standard, Ada 95, introduces a new mechanism called streams that allows structured data to be flattened. Streams are sequences of elements comprising values from possibly different types. Ada 95 allows programmers to develop their streams following the standard abstract class interface. In this paper we show how to use the stream concept for developing new features to provide internal program data saving suitable for fault tolerance and persistence. A hierarchy of different storage types, useful in different application domains, is introduced. The standard stream interface is extended, making it possible for programmers to have a better control of the way streams work by separating storage medium control from the actual stream type using the design patterns. The convenience of this new interface is demonstrated by developing a generic package allowing any non-limited object to be written into a storage device. It can be used for providing data persistence and as a state restoration feature in schemes used for tolerating software design faults.

This paper describes proposed extensions to the Ada95 programming language to provide support for persistent programming. The extensions support transparent migration of data between a program's address space and a persistent store in a way that preserves both type safety and encapsulation of ADT's. 1 Introduction Ada has recently undergone an intensive and major review and update. The result of this is the new programming language Ada95 (ISO 1995) which is, in the main, backward compatible with Ada83. Two of the principle changes to Ada was the addition of appropriate semantic constructs to change Ada from an objectbased language to a fully fledged object-oriented language and the provision of annexes defining additional language capabilities for specific user communities. In this paper we consider further extensions to Ada95 by way of the introduction of a persistence annex to provide persistent programming support to Ada. We call this revision persistent Ada95 to distinguish it fr...

. Research into persistent programming languages and systems in recent years has shown that the technology is useful for developing complex software in many problem domains. This paper explores the issues and consequences of adding persistence to Ada95. The persistence extensions support transparent migration of objects between a program's address space and a persistent store in a way that preserves both type safety and encapsulation of abstract data types. Keywords and Phrases: Kinds of systems: persistent systems; Ada95; object-oriented technology. 1 Introduction Ada has recently undergone an intensive and major review and update. The result of this is the new programming language Ada95[23] which is, in the main, backward compatible with Ada83[36]. Two of the principle changes to Ada were the addition of new constructs to change it from an object-based language to a fully fledged object-oriented language and the provision of annexes defining additional language capabilities for spec...

: In the CORBA environment, a support for persistence is standardized by the COS Persistent Object Service document. The standard, however, only describes general guidelines, not providing the necessary details. The thesis aims at designing a working persistence support, analyzing the missing details in the process. To remove thus discovered drawbacks of the standard, a new standard for persistence is proposed. 2 1 Contents 1 Contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 2 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 2.1 TOCOOS and POS 5 2.2 The goals of the thesis 5 2.3 Structure of the text 6 3 Context of the thesis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 3.1 Persistence 7 3.1.1 Technical issues 7 3.1.2 Projects supporting persistence 8 3.1.2.1 Aperto...

Serialization is the process that transforms the state of a software object into a sequence of bytes. Serialization is useful, for example, to store the value of an object in persistent memory or to send it through a network channel. Ada provides