Dual operating system computer

摘要

A mainframe computing system is adapted to be loaded with one of a plurality of different operating systems and different associated microcode to provide a computing system which is capable of running user programs adapted to be executed by the loaded operated system comprises a main memory for receiving the desired operating system coupled to a system bus. An instruction processor and an input/output control processor are coupled to the system bus and are provided with an instruction register for presenting user program instructions to the processors. The processor means have associated therewith microcode storage memory which receive and store a set of microcode instructions to be performed by the processors according to the program instruction stored in the instruction register. The stored microcode comprises primary microcode instructions to carry out each of the instructions in the instruction register means. No compiling or emulation is necessary to provide a software configurable computing system adapted to run user programs according to one of a plurality of operating systems loadable in the main memory.