an automatically configurable i / o board and associated software avoids any need for jumpers , switches , or other configuration changes upon installation of the board . utilization of the main computer capability to select addresses and values likely to be available involves an installation or other routine which arrives at a unique parameter through common commands and repetitive execution . uniqueness of the parameter or address is accomplished by checking for use elsewhere in the system prior to operation of the board . steps are taken to avoid any inappropriate changes in conflicting i / o boards by activating and disabling components such as the control register on the board through use of a state machine , by using non - destructive commands for initial checks , by tristating unnecessary lines , and by re - initializing registers whenever a conflict is encountered . additionally no address space is used to activate the board .