SIMPLE PATCH CANCELLING SYSTEM

PURPOSE:To attain the cancel of an applied patch by preserving the old machine word information within a processor when the patch is applied to a real machine from a processor different from the real machine. CONSTITUTION:The patch information corresponding to a patch area 4 in a program area 3 on a memory 1 of a real machine is produced in another processor as the machine word information and stored to a memory 2 as the patch information 5. Then the patch processing is indicated to the area 4 with operation of an operator. Thus the instruction of the area 4 is stored to the memory 2 as the old machine word information 8. At the same time, the patch information corresponding to the area 4 is set at the area 4 and a patch area 11 from the information 5. The contents of the patch information are stored to the area 11, and the address of the patch information is stored to the area 4. Thus the information 8 can be applied to the area 4 as the patch information by indicating the patch cancel with operation of the operator.