APPLICATION OF ANALYTICAL MODEL 79 DATA BASE DESCRIPTION \ CHARACTERISTICS - STRUCTURE MODELS r I / O PROCESSING TIME REQUIRED FOR THE STORAGE STRUCTURE APPLICATION PARAMETERS

The File Design Analyzer is a software package which evaluates well-known data base storage structures and access methods in terms of secondary storage processing time and storage overhead required to service a set of user applications. It implements a first-order analytical model to specifically evaluate sequential, indexed sequential, direct access, and inverted multilist storage structures. Interaction with the package is available in conversational mode, enabling the experienced analyst to conduct on-line sensitivity analysis. The paper describes three extensions which converted an abstract conceptual model into a practical tool for evaluation of existing or proposed data base designs: batched transactions, multi-access interference due to shared secondaty storage, and analysis of variable record size. A case study from a real system illustrates the potential of the File Design Analyzer to provide insight regarding the optimal choice of physical parameters within a specified storage structure and to effectively compare alternative storage structures for a particular set of applications.