Redundant system using object-oriented program and method for rescuing object-oriented program

A redundant system using an object-oriented program, wherein the system has a plurality of devices comprising:

• a synchronization memory which stores one or more instances of objects according to the order of the processing, wherein each of instances includes;
• a virtual function discrimination information which is used for discriminating a memory area where a virtual function corresponding to the object is stored;
• a class information which is used for discriminating a class corresponding to the object;
• and
• an object data which is used for processing the object;
• a function memory which stores plural kinds of virtual functions generated for each process to be carried out by the object;
• an application program which reads the instance from the synchronization memory and writes it to a synchronization memory of the other device;
• and
• an instance management class which, when a device newly put in the active state reproduces a process of an object, discriminates the class corresponding to the object using the class information, and rewrites the virtual function discrimination information.