Patent ID: 7882391

Claim:
A computer system comprising: a terminal device; a main system to provide a management service to said terminal device registered in management information; a backup system to stand by for continuing to provide the management service in case of occurrence of a fault in the main system; and a monitoring device to monitor an operation status of said main system, said monitoring device including: a monitoring unit to transmit a status check to said main system and to receive a response transmitted from said main system in response to the status check, thus monitoring a normal operation of said main system; a fault detecting unit to determine, if unable to receive the response to the status check under a predetermined condition, that the fault occurs in said main system; and a startup request transmitting unit to transmit, if said fault detecting unit determines that the fault occurs, a management service startup request to said backup system, said terminal device including: a registration request unit to transmit the registration request for registering in the management information to said main system or said backup system, to receive registration completed notification sent from said backup system in response to the registration request, to transmit the registration request to said main system, and to transmit, if not receiving the registration completed notification to the registration request under a predetermined condition, the registration request to said backup system, said backup system including: a management service startup unit to stand by in a status of not registering said terminal device in the management information even when receiving the registration request, to start providing the management service by starting up the management service when receiving the startup request, and to start the registration in the management information in response to the registration request.