2452	 Evaluation and Selection of File Organization-A Model and System	 This work first discusses the factors that affect file data base organization performance an elusive subject and then presents a methodology a model and a programmed system to estimate primarily total storage costs and average access time of several file organizations given a specific data base query characterization and device-related specifications. Based on these estimates an appropriate file structure may be selected for the specific situation. The system is a convenient tool to study file structures and to facilitate as much as possible the process of data base structure design and evaluation. file organization file structures file management file organization performance file organization model file structure design secondary index organization simulation data base access time storage requirement data base analysis data management
