Processor having plural initial loading programs for loading different operating systems

摘要

An information processor with a read only memory ROM stores a plurality of initial program loader (IPL) programs. The ROM memory has address inputs divided into two parts used to access each IPL program. One part of the address inputs of the ROM memory is connected to an address bus from a central processing unit (CPU) in order to be used to access the contents of one of the programs. The other part of the address inputs of said ROM memory is connected to an IPL setting part or switching which sets or selects a desired one of said plurality of IPL programs. The IPL setting part includes a plurality of switches connected to upper bit terminals of the ROM address inputs.