89 results about "Servo track writing" patented technology

A disk drive is disclosed including a disk, an actuator arm, a head attached to a distal end of the actuator arm, a mechanical position sensor operable to generate a position signal representing a position of the head relative to the disk, and a voice coil motor for rotating the actuator arm about a pivot. The disk is rotated at a predetermined velocity, a control signal is generated in response to the position signal generated by the mechanical position sensor, and the control signal is applied to the voice coil motor in order to seek the head radially over the disk while writing a spiral track to the disk. The spiral track is then processed to maintain the head along a servo track while writing product servo sectors along the servo track.

A perpendicular media recording (PMR) servo track writer (STW) system and method for writing servo sectors onto a disk is disclosed. The servo writer includes a head positioner to position a head of a head disk assembly (HDA) relative to a disk, wherein the head writes servo sectors onto the disk with a perpendicular flux. The servo writer includes a controller to control the head positioner such that the head writes servo sectors onto the disk from one of an inner diameter (ID) or an outer diameter (OD) of the disk to a middle diameter (MD) of the disk, respectively, followed by writing servo sectors between the other of the OD or the ID of the disk to the MD of the disk, respectively.

Embodiments of the invention provide a disk device capable of writing highly accurate servo data using an extremely simple technique, and a manufacturing method therefor. According to one embodiment, a method for manufacturing a disk device includes: mounting a magnetic disk and each assembly for driving the magnetic disk, such as an SPM and a VCM, in a base and attaching a top cover so as to seal the enclosure (made up of the base and the top cover) with each assembly of the HDD therein; replacing the air within the hard disk assembly (HDA) with a gas having a lower density than air, such as He; writing servo data to the magnetic disk in a self servo track write operation; and replacing the gas within the HDA with air.

Servo tracks are written onto different disk surfaces using multiple recording heads within a disk drive without requiring a servo writing machine or clean room conditions. Microactuators in the reference heads in the disk drive are capable of independent motion with respect to one another, which allows the servo tracks to be written to the disk surfaces. The process begins as the recording heads are biased against a crash stop, and then moved to an adjacent track. One of the heads writes a reference track at this adjacent track position when a microactuator of the head is centered. This reference head then follows the reference track with its microactuator centered, while the other recording heads move in the radial direction to write servo information on their respective tracks. Reference tracks are then successively used to write the servo information as the recording heads move in a direction away from the crash stop.

A method for writing servo information onto a disk of a hard disk drive. The method includes writing a reference servo pattern onto a track of a disk with an off-line servo track writer. The reference servo pattern has less servo bits than the final pattern allowing the off-line writer to write in a single pass. The disk is then assembled into a hard disk drive assembly and a final servo pattern is written onto the track. The final pattern can also be written with two passes. The single pass writing process reduces the time required to write the servo information. Additionally, the off-line servo track writer can write servo on a plurality of disk at the same time, further reducing the process time for writing servo and mass producing hard disk drives.

Disk drive preconditioning allows the head-disk interface to be burnished or worn so that head-disk interference is reduced or eliminated before servo track writing. The head is positioned closer to the disk than the normal fly height during a preconditioning sweep and then returns to the normal fly height during servo track writing.

Magnetic alignment marks are recorded on a recording surface of a magnetic hard disk to mark the location where the disk is abutted against the hub of the spindle of a multiple-disk servo-writer. The alignment marks for each recording surface may be different so as to distinguish between top and bottom disk surfaces so that when the discs are assembled onto the spindle of a disk drive they may be assembled with the proper orientation, i.e., the top surface is mounted “up.” The marks may be large, low frequency patterns that are both written and detected by non contact means other than the servo-track writer's or the disk drive's heads.

A servo writer system for a disk drive uses the reader element of a magnetic transducer head in the disk drive to read head position information during servo writing of the disk drive. A positioning system in the servo writer uses both the head position information and actuator position information, as feedback signals to accurately position the transducer during servo writing, resulting in high quality servo tracks.

A servo track writing apparatus (10) for writing servo tracks (16) on a media disk (14) of a disk drive assembly (12) having a Positioning arm (22) with a through hole (28) therein. The writing apparatus (10) has a laser source (29) which directs a source beam (30) through a polarizing beam splitter (32) and a quarter-wave plate (34) to either pass through the through hole (28) and reflect off of the media disk (14) as a reflected beam (38), or to be reflected from regions of the positioning arm (22) proximate to the through hole (28) as a reflected beam (56). The writing apparatus (10) further has a remote tracking arm (42) with two photodiodes (40a, 40b) suitably mounted thereon to receive the reflected beams (38, 56). The tracking arm (42) is caused by a motive means (54) to precisely track the positioning arm (22) of the disk drive assembly (12). A laser interferometer (58) is then used to detect an optical target (60) mounted on the tracking arm (42) and determine positioning for writing of the servo track (16).

One embodiment of the present invention is method for testing a reading function of a printed circuit board of a disk drive or a servo track writer that includes: (a) providing a test pattern; (b) processing the test pattern to generate a digital signal series; (c) differentiating the digital signal series to provide a differentiated signal series; (d) applying the differentiated signal series as input to the printed circuit board; and (e) comparing an output from the printed circuit board with the test pattern.

A servo writer that writes servo information onto a disk of a hard disk drive. The servo writer can write servo information onto a disk of a hard disk drive while the disk is within an inner chamber of a housing. The rotating disk creates a flow of fluid within the inner chamber. The disk is rotated during the servo writing process. The density of a fluid medium within the inner chamber is controlled by a medium control system so that the density of the medium is less than the density of air at one atmosphere. Lowering the density decreases the amplitude of vibrational forces created by the flow of fluid. Decreasing the amplitude reduces errors in the servo writing process. The density can be reduced by pulling a vacuum within the inner chamber. The density can also be reduced by filling the inner chamber with a gas such as helium that has a lower density than air.