Abstract: Single and double density servo-tracks are written on the servo-surface of a rotating disc pack with a single transducer carried by a transducer head assembly driven by a screw shaft. The screw shaft is incrementally rotated by a first fixed angular distance and a second fixed angular distance when writing single and double density tracks, respectively. The transducer has a gap width greater than the width of the widest track to be written, and the tracks are sequentially recorded by recording a preliminary track having a width equal to the width of the transducer gap, radially translating the transducer by an amount equal to the desired track width, erasing the portion of the preliminary track overlapping the transducer gap to form a track having the correct width and repeating the recording and erasing steps until all tracks have been so recorded.

Abstract: An improved flexible magnetic recording disc assembly comprising an envelope and a flexible recording disc rotatably received in the envelope, the disc having an annular reinforcement member concentrically arranged adjacent the central mounting aperture of the disc. Two embodiments are disclosed: a first having a single annular reinforcement member secured to the spindle side of the flexible disc; and a second having a pair of annular reinforcement members disposed on opposite surfaces of the disc. The reinforcement member has an axial thickness in the range from about 2 to about 7 mils to provide sufficient structural rigidity to resist crinkling and flaring during use; a static and dynamic coefficient of friction not less than about 0.3, and a total electrical resistance measured in the longitudinal axial direction in the range of about 1 ohm to about 50 megohms to facilitate dissipation of static electrical charges which may build up on the recording surfaces of the disc.

Abstract: A method and apparatus for treating the recording layer of flexible recording elements to remove protruding agglomerated particles formed during the fabrication process and to provide an extremely smooth surface finish on the order of 1.8AA or less. Several embodiments are disclosed for treating both annular recording discs and roll type recording media. The method comprises burnishing the recording layer surface with a hard smooth abrasive member while supporting the flexible recording element on a resilient backing surface and observing key parameters.