Abstract: A method of operating a disk drive including providing the disk drive. The disk drive includes a disk with data tracks and an actuator with a slider including a perpendicular magnetic write head. The write head includes leading and trailing sides defining a taper angle. The write head and the actuator define a maximum skew angle with respect to the data tracks. The maximum skew angle being greater than the taper angle. The method further includes rotating the slider during operation of the disk drive to reduce a difference between the skew and taper angles for aligning the write head with the data tracks.

Abstract: A disk drive is disclosed comprising a disk having a plurality of servo sectors forming a plurality of substantially linear servo wedges extending from an outer diameter of the disk to an inner diameter of the disk, wherein each servo sector is written using perpendicular magnetic recording. The disk drive further comprises a head coupled to a distal end of an actuator arm that is rotated by a rotary actuator about a pivot in order to actuate the head radially over the disk in a substantially arcuate path.

Abstract: A method of selecting a track density for a disk surface of a disk drive is disclosed. A first pattern is written along a circumferential path of the disk surface, wherein the first circumferential path comprise a first set of arcuate sections interleaved with a second set of arcuate sections. A second pattern is written radially offset from the circumferential path during time intervals corresponding to the first set of arcuate sections. The head is positioned substantially over the center of the first circumferential path and during time intervals corresponding to the second set of arcuate sections, the first pattern is read to generate a first read signal amplitude measurement A0, and during time intervals corresponding to the first set of arcuate sections, the first pattern is read to generate a second read signal amplitude measurement A1. A track density is selected in response to A0 and A1, wherein the track density is for use in writing embedded servo sectors to the disk surface.

Abstract: A disk drive and related method, the disk drive including a rotating magnetic disk and read and write elements for reading and writing data from and to the rotating magnetic disk, comprising: a magnetic characterization pattern recorded on the rotating magnetic disk for use in characterizing widths of the read and write elements using a plurality of track profiles of differing width. The magnetic characterization pattern is uniquely formed from a first plurality of characterization segments of a first radial width disposed circumferentially about a full circumference track on the rotating magnetic disk and a second plurality of characterization segments of a second radial width that is different than the first radial width disposed circumferentially about the same full circumference track on the rotating magnetic disk. The beneficial result is that two measurements can be accomplished within the STW in roughly the same time it ordinarily takes to accomplish only one.

Abstract: An ionization-type fire detector having a pair of ionized chambers, one of which is arranged so that products of combustion can flow therethrough while the other is substantially isolated from the products of combustion. As a result, when combustion products are present, the electrical conductivity in one chamber is different than the other, and this condition is sensed to provide a fire alarm signal. The first-mentioned ionized chamber is defined by inner and outer shells of plastic material which are suitably spaced from each other and with the inner surface of the outer shell being provided with a conductive coating. The spaced plastic surfaces are curved, and one of the shells defines a cavity which forms at least a part of said first-mentioned chamber. It has been found that this minimizes the adverse effects caused by wind drafts which otherwise can affect the electrical conductivity in the first chamber and provide an erroneous fire alarm signal.