Stocker and changer for information recording media

A stocker for information recording media, which is capable of stocking the information recording media and is to be loaded in a changer or unloaded therefrom, which comprises:

• a trace record device for providing a trace of lodging or dislodging operation of at least one information recording medium when said lodging or dislodging operation is carried out in an off-line condition, said trace record device being mechanical and comprising a movable member, said movable member being movable between a first, position exhibiting that said lodging or dislodging operation has not as yet been carried out and a second position exhibiting that said lodging or dislodging operation has already been carried out, wherein said trace record device is adapted to record said trace in interlocking relation with motion of a knob, which determines whether or not said at least one information recording medium is dislodgeable from said stocker.