Processor implementation-specific instructions save a processor state in a system memory and attempt to correct the error. The silicon nitride film and the silicon oxynitride film are patterned. A paired connection between the media devices is completed after a corresponding confirmation message from the second device is received within a second predetermined time period. In an unlocking process, the moving unit is forced to move along a first path and drives the locking unit. A user interface unit outputs a display requesting signal when an authorized user requests to view letters for the user and outputs an account control signal having information selected by the authorized user from the displayed information.