When the system boots and a new device is discovered, the system checks the ODM for a device definition that matches the new device. For a disk device, this is based on the SCSI inquiry command. If a match is found, then a customized definition (CuDv and CuAt) is built for that device using the default attributes for that device definition. The new device then has the description based in the ODM for that device (for example, 2105 or LVD SCSI disk drive). This customized definition is persistent and will remain until the device is removed from the system. An active device will have an available status and is ready for use. A device that was available, but has been physically removed from the system will have a defined status and cannot be used.