2313	 The Evolution of Storage Structures	 Data base management systems have grown rapidly in their power and complexity over the -year history of data processing on commercially available computers. The original concepts have split and new terms have been adopted to name and refer to these concepts. The Data Structure Diagram graphic technique is used to illustrate the splitting of the concepts and the structural relations which exist between these concepts at each point in the evolution. block cylinder device field extent file page record physical record logical record track volume entity set entity class set class data structure diagram storage structure physical storage structure logical storage structure storage allocation structure Integrated Data Store index sequential hash randomize item
