Description
The Model 5 and FCP (the lower-end models) were developed by adding functions for file processing to the FCP to achieve sharing of hardware, such as register stacks for each level, dedicated instructions using firmware, and high-performance coupling capability with the CPU. Prototypes of the Model 5 and FCP were completed simultaneously in December 1979. Prototyping of the Model 15 and 35 finished in September 1980. For the Model 25, the plan was changed to a new design using high-performance logic LSI and high-density mounting technology throughout, and the prototype was finished in April 1981.
