A marking system may hold a container from which markers are dispensed and identify a marker characteristic regarding the markers in the container. A VCM driver comprises first and second transistors forming a common collector amplifier for sensing a current flowing through a voice coil of the VCM. The patron in effect becomes his or her own DJ, VJ or director-producer. The mediator verifies the external user’s authenticity. The fixing means of the structure comprise at least a fast clutch with a tenon and mortise joint wherein a tenon element, fixed to the profile, and a mortise element, intended for being fixed to the hull, have respective tenons and mortise being mutually engaged in a longitudinally sliding way. The system may read data cells using a current sensing one or two step binary search.