Helios Inc.

Konica Corporation

Konishiroku Photo Industry Co., Ltd.

Phase Metrics, Inc.

Alex Moraru

Bill Richard Baker

Peter Skalon

Kechen Cheng

Yechel A Yassif

The present invention is a clock head assembly that provides reference clock signals during servo writing of a magnetic disk in a hard drive. The clock head assembly includes a clock head that is pivotably mounted to a housing. The housing encloses a disk mounted to a spindle. The spindle is attached to the spindle motor of a hard disk drive through an opening in the housing. The spindle motor of the disk drive rotates the spindle and disk of the clock head assembly. The clock head is coupled to a cam that is manually actuated by a lever to move the clock head arm assembly between a loaded position and an unloaded position. During servo writing, the clock head is loaded onto the disk so that reference clock signals may be read from the disk and provided to a servo controller which utilizes the clock signals to write servo information onto the disk within the hard disk drive. Upon completion of servo writing, the clock head assembly is detached from the hard disk drive. The clock head assembly may be attached to the hard drive assembly in a non-clean room environment. In addition, the servo writing process may be conducted in a non-clean room environment.

Method and apparatus for providing a clock assembly

An embodiment of the present invention is a head disk assembly (HDA) simulator that outputs a flexible, totally electronic simulation of an HDA. It outputs a programmable standard HDA signal. As such the HDA simulator generates the head signal that a functioning, already servo-written HDA would provide. This signal can be ideal, eliminating any anomalies and inconsistencies inherent in electromechanical devices. Quantifiable amounts of anomalies can be systematically introduced to allow design margin testing. The HDA simulator is controlled in two ways. First, by allowing a user to choose items from four menus. And second, by allowing the user to use a built-in text editor to edit ASCII files that control the servo patterns and simulator operation. Independent channels of repetitive signals are available to specify sync, servo and data patterns. For any given simulated head position, simulated adjacent tracks are generated and then mixed-in at an appropriate ratio. Signals that are unique to each track are also available, to accommodate special requirements such as Grey code.

Head disk assembly simulator

A microcomputer controlled media and disk testing system having a media servowriting subsystem and a certification subsystem. The servowriting subsystem comprises a precision magnetic read/write (R/W) head positioning device based on a laser positioning device and pattern generating and writing circuitry. The certification subsystem comprises of an apparatus to open bit windows and adjust thresholds and to assess the quality and nature of defects from the positions of bits and their analog characteristics when read back relative to such windows.

Servowriter/certifier

A flexible data disk has consecutive servo tracks having a synchronization and alternate synchronization mark. The synchronization and alternate synchronization marks in each servo sector are radially aligned. Four magnetic pulses represent a synchronization mark and two magnetic pulses represent an alternate synchronization mark. The disk drive system will read and identify the synchronization marks and alternate synchronization marks and start generating timing pulses as appropriate. The servo bursts can then be read allowing the disk drive system to center the transducer head over the data tracks.

Magnetic media and servo synchronization method

A servo system intermittently samples servo sectors from a data disk to obtain the position of the read/write head and to maintain an on-track alignment. A glass scale measures the movement of the transducer head and provides a velocity signal. An integrator integrates the velocity signal to produce a fill-in position signal. This fill-in position signal is added to the position signal from the last sampled servo sector to provide a position compensator with position information when the head is in between servo sectors. An on-track detector circuit and a damping circuit heavily damp movement of the transducer head when the head is in the on-track position. A gain circuit modifies the signal going to the position compensator in order to compensate for misclamping and imperfections in the data disk. The position compensator includes a tilt circuit which compensates for tilting of the disk drive from a non-horizontal position.

Growing community of inventors

Fremont, CA, United States of America

Alex Moraru