Kenneth Chisholm

An Approach to Persistent Programming

This paper presents the identification of a new programming language concept and reports our initial investigations of its utility. The concept is to identify persistence as an orthogonal property of data, independent of data type and the way in which data is manipulated. This is expressed by the principle that all data objects, independent of their data type, should have the same rights to persistence or transience. We expect to achieve persistent independent programming, so that the same code is applicable to data of any persistence. We have designed a language PS-algol by using these ideas and constructed a number of implementations. The experience gained is reported here, as a step in the task of achieving languages with proper accommodation for persistent programming.

PS-algol: an algol with a persistent heap

PS-algol is a dialect of algol for the programming of problems that would normally require a database management system. It supports a persistent heap, and an associative store; it has embedded within the language features to support tasks normally carried out by filing systems or database management systems.

Algorithms for a persistent heap

PS‐Algol is a dialect of Algol for the programming of problems that would normally require a database management system. It supports a persistent heap, and an associative store; it has embedded within the language features to support tasks normally carried out by filing systems or database management systems.

CMS—A chunk management system

The chunk manager provides simple transaction management, concurrency control and allocates, administers and retrieves apparently contiguous chunks of data of arbitrary and varying size on disc. This system is designed to permit students and research workers to rapidly assemble and test their own DBMS, supporting any data model. Currently it is being used to support PS‐Algol, an implementation of DAPLEX, a relational system and student database exercises.