Interactive computers are providing more services to greater numbers of users. However, before such systems can be economically applied to public education, the cost of high performance memory must be reduced. By using massive amounts of serial memory in conjunction with a highly sophisticated memory controller, a system was constructed which performs as well as random access memory, but at less cost. To demonstrate the control structure, and to determine the applicability of the memory system to PLATO computer-based educational system, a memory controller was installed and operated, a small memory system was introduced, and software was written to slave the memory controller system to the operation of the PLATO system. (EMH)