CMS—A chunk management system

Abstract

Abstract 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. A chunk is similar to the common meaning of ‘record’ except that there is no implication of internal structure or consistent and static size. An efficient table processing capability is also provided. Locking and access control are implemented at the bag level to prevent conflicting use of data without excessive operating cost. The problems associated with concurrent access of shared bags have been studied and the currently implemented and future proposed solutions are discussed.