A relatively new area of research in information theory concerns coding and information capacity concepts for storage systems. As new high.density recording media are developed ; e.g., optical and magneto.optical techniques, there is need for mathematical models for a variety of storage systems in order that maximum efficiency and reliability can be attained. This project is concerned with the development of these models as well as the development of good codes for efficient storage. The implementation and complexity aspects of the codes are examined and the information storage capacities of the various models are determined. The models include "Write.once memories" (WOM), "Write.unidirectional memories" (WUM), and their unification and generalization, "Write.efficient memories" (WEM).
