Flexible-disk magnetic memory

To develop a flexible-disk magnetic memory, an experimental investigation of a new type of noncontact suspension mechanism for the flexible disk has been carried out. This suspension mechanism has an aerodynamic step thrust bearing and an aerodynamic cylindrical thrust bearing in which the magnetic heads are imbedded. The flexible disk is set between the bearings. Rotational motion of the flexible disk generates aerodynamic pressure between the flexible disk and the bearings, and keeps a small stable clearance ranging from 5 μm to 10 μm between the flexible disk and the magnetic heads. A prototype model of the flexible-disk memory has been manufactured. This model has a thin disk of mylar coated by conventional γ-oxide magnetic layer (100 mm in diameter, 33 μm in thickness). One track is capable of storing about 2000 bits. The maximum number of tracks is 36. The rotational speed of the disk is 1500 r/m or 3000 r/m. No decrease of readout signal was observed during the shock test in which the model was subjected to more than 20 G external acceleration.