Apparatus is provided for repairing a valve of a heart of a patient which includes an annulus and at least first and second leaflets. The injector is provided with a nozzle insertable into the socket. The drivetrain includes a plurality of links that are associated with drive chain rollers. After writing calibration data to the second fly height calibration track, the first fly height calibration track is read in order to calibrate the fly height control signal applied to the fly height actuator. The invention also relates to a reading method and a storage medium having an individualized hologram. The method includes forming an interlevel dielectric layer on a substrate; forming at least one metal line on the ILD layer; forming a metal barrier on the ILD layer and the metal line; reforming the surface of the metal barrier by performing a reforming process using an inert gas; and forming a metal pad on the metal barrier.