A plasma processing apparatus includes a chamber for containing a substrate to be processed, a gas supply unit for supplying a processing gas into the chamber, and a microwave introducing unit for introducing plasma generating microwaves into the chamber. The buckle includes an engagement and disengagement system in which the insertion body is inserted into the buckle body. The computer system then issues a request to create on the first storage device a second disk image based on the snapshot, and copies the snapshot on to a second storage device.