A dual accessor library is equipped to maintain consistent dual copies of vital
product data (VPD) or other such metadata. For each accessor, the library includes
various associated components, including a controller to manage the media accessor,
VPD or other such metadata containing information representing prescribed types
of library properties, and a version code corresponding to the VPD. Each controller
advances the associated version code in response to VPD changes. Responsive to
predetermined stimuli, the accessor controllers compare their associated version
codes and if the version codes do not match, updating the older VPD with contents
of the newer VPD.
