PURPOSE: To automatically generate and load a load module corresponding to a different kind of CPU each time the CPU is replaced by converting a source module into the load module of the CPU.

CONSTITUTION: A CPU-B1.3 is changed into a different kind of CPU-C1.4. The replacing CPU-C1.4 executes the IPL program in the ROM in the CPU. The IPL program checks whether or not there is a load module for the CPU-C in an auxiliary storage device 10 first. When there is not the load module for the CPU-C, system data 14 are read out to check the storage locations of a compiler C 25 and a linker C 26. In this case, the compiler C 25 and linker C 26 are stored in the ROM in the CPU-C, so the source module 13 is compiled and linked. Then the generated load module C 15 for the CPU-C is loaded into the CPU-C from the auxiliary storage device 10.