Cartridge type recording medium, associated apparatus and methodology of disc detection

摘要

A recording medium is provided wherein type determination and writing possibility determination is enabled for various types of disks. Opening and closing structure functions to open and close a detection hole of a cartridge. The structure forms a plane substantially horizontal level with a reference plane of the cartridge at a position of a detection hole when the detection hole is in a closed state. The cartridge has at least a first detection hole and a second detection hole formed therein. The second detection hole (H 1 ) is opened and closed by the opening and closing structure, and the first detection hole (H 0 ) is in an open state at all times.