Disk cartridge with write protect mechanism

A disk cartridge with a write protect mechanism comprising:

• a cassette casing for rotatably housing a recording medium disk therein, the cassette casing including a first half and a second half, each of which have upstanding peripheral side walls and wherein the sidewalls of the first half abut against the side walls of the second half;
• a manually operable write protect tab;
• a housing space provided in the cassette casing for movably receiving the manually operable write protect tab therein to allow the write protect tab to slide between different indicating positions wherein a first side wall of the first half and an abutting, second side wall of the second half each have a first recess and a second recess, respectively, therein which together form an opening from the housing space to the outside of the cassette casing;
• wherein the first and second sidewalls at least in the vicinity of the opening are elastically deformable and the opening is dimensioned to allow insertion of the write protect tab into the housing space subject to elastic expansion of the opening as the write protect tab is inserted into the opening so as to capture the inserted write protect tab within the housing space one the write protect tab is fully inserted into the housing space.