Abstract: Sealing structures are provided to prevent contamination entry into a removable disk cartridge hard disk drive. The outer end of the cartridge is fitted with a seal abutment structure, which is slightly wider and thicker than the rest of the cartridge. The seal abutment structure has a chamfered ring surface thereabout facing the inner end of the cartridge. The cartridge is inserted into the disk drive through a pair of doors that normally seal the interior of the disk drive until the chamfered ring surface engages a sealing gasket positioned about an opening to the interior of the disk drive behind the doors, so that when the disk is spun, the air centrifugally pumped can not pull dust particles in from the outside environment.