PSEUDO DEVICE

PURPOSE: To efficiently develop firmware/software by providing a control part to be monitored by a memory means storing the software prepared so as to transmit the same response as the response transmitted when a command is inputted and the mounting/unmounting information on the control part to be monitored and a control means. CONSTITUTION: The command from a main monitoring control part is inputted via the command reception part 51 within a pseudo device package. A CPU 55 detects the destination of the command and transmits the command to a corresponded control package to be monitored via a command transmission part 53 if the control package to be monitored is mounted. The inputted command is decoded at this stage and a response is transmitted. This response is taken out in a response reception part 54 and the response is transmitted to the main monitoring control part via a response transmission part 52. If the destination is a pseudo package, the response which coincides in the destination and is corresponding to the received command of the responses stored in a memory 56 is read and is transmitted to the main monitoring control part via the response transmission part 52.