Abstract: A disk for a disk drive uses a circular platter having first and second sides and a circumferential edge. The circumferential edge of the disk has four symmetrically spaced apart shadows and a fifth or additional shadow that gives the disk an asymmetrical shadow signature. The fifth shadow is offset relative to the other shadows, which have congruent arcuate lengths and separation. The fifth shadow has an arcuate length that is about half as long as those of the other shadows, and is closely spaced adjacent to one of the other shadows. The asymmetric shadow signatures of the disk is used to precisely determine both the circumferential position of the platters and their planar orientation (i.e., A-side or B-side). For example, when the disk is mounted on a tool spindle and rotated, an optical detector detects the pattern of the shadows and feeds the data to a computer system. The rotational position of the spindle also is relayed to the computer for coordinating the processing of the rotating disk.

Abstract: An apparatus and method for detecting and marking delamination defects on thin film disks are disclosed. The apparatus includes a read/write (R/W) head and a burnishing head mounted on separate arms that access the disk while spinning on the test stand. The controller uses the R/W head to perform an initial magnetic test of selected areas on the disk to establish an initial defect map. The burnish head is then flown over the surface for an extended time to accelerate and open up the latent delamination defects by impacting protruding material. The R/W head is then used to perform a second magnetic test which is compared against the first test to identify the delamination defects which have been developed by the burnishing. The delamination defects are then marked with a magnetic pattern which aids in optically locating the defect during subsequent failure analysis.

Abstract: A calibration method for determining the flying height of a glide slider for disk glide height testing is disclosed. The method utilizes a disk with bumps in situ on a disk glide height tester. The method automatically takes into account disk topography, mounting tolerances, and slider roll.

Abstract: A disk for calibrating glide heads utilizes a dual-zone configuration of multiple laser melt bumps having selected heights. Averaging the PZT response over many bumps significantly narrows the response distribution, resulting in greater certainty and correlation of the PZT amplitude to bump height. The multiple calibration bumps are circumferentially arranged on a disk surface at a selected radius in a ring-like manner. A second head cleaning zone is provided near the inner diameter of the disk to provide for increased reproducibility of the PZT calibration response. The second zone is densely textured and serves to clean the glide head prior to its use in the calibration zone.

Abstract: A disk for a disk drive uses a circular platter having first and second sides and a circumferential edge. The circumferential edge of the disk has four symmetrically spaced apart shadows and a fifth or additional shadow that gives the disk an asymmetrical shadow signature. The fifth shadow is offset relative to the other shadows, which have congruent arcuate lengths and separation. The fifth shadow has an arcuate length that is about half as long as those of the other shadows, and is closely spaced adjacent to one of the other shadows. The asymmetric shadow signatures of the disk is used to precisely determine both the circumferential position of the platters and their planar orientation (i.e., A-side or B-side). For example, when the disk is mounted on a tool spindle and rotated, an optical detector detects the pattern of the shadows and feeds the data to a computer system. The rotational position of the spindle also is relayed to the computer for coordinating the processing of the rotating disk.