A disk file of the kind employing a vented hub assembly and slotted spacers between disks to provide a passage for circulatory airflow employs a filter assembly extending circumferentially around the axial region of the hub assembly. The primary path for airflow is from a high pressure region at the periphery of the disks, through the filter assembly into the vented hub assembly and out again via the slotted spacers. A parallel leakage path between the filter itself and the hub assembly is limited by making the separation between a substantially planar surface of the filter assembly and the adjacent disk uniform and very small. Airflow rates through the filter are consequently enhanced.