Patent ID: 7694292

Claim:
A computer implemented method of maintaining a mission critical system by a first user so as to be available for use by a second user, the system including hardware and computer data on which the operation of the hardware depends, the system further including a controller coupled with the hardware, the method comprising: providing storage coupled with the hardware and the controller and operative to store the computer data, the storage comprising first and second portions; storing the computer data in the first portion of the storage; operating the hardware based on the computer data stored in the first portion; receiving, by the controller via a first user interface, an indication from the first user to make the system unavailable for use during a maintenance operation and, in response thereto, making, by the controller, the system unavailable for use during the maintenance operation and, substantially concurrently therewith, copying, by the controller, the computer data from the first portion to the second portion and subsequently allowing, by the controller, the first user to modify a copy of the computer data stored in the second portion; receiving, by the controller via a second user interface while the system is unavailable, an indication from the second user to make the system available for use and, in response thereto: making, by the controller, the system available for use and operating the system based on the second portion comprising the modified copy of the computer data, if an indication has been received from the first user that the first user has completed modifying the copy of the computer data stored in the second portion prior to the receiving of the indication to make the system available for use; and otherwise making the system available for use by interrupting, via the first user interface, the first user's modification of the copy of the computer data stored in the second portion and, subsequent thereto, operating the system based on the computer data stored in the first portion.