Abstract: A system and method for maintaining a prescribed track pitch in an optical storage system wherein a second radiation beam is aligned a desired distance from a first radiation beam, the first radiation beam being controllably steered to follow a previously written data track on a record carrier used within the optical storage system. A write alignment servo aligns the second radiation beam the prescribed distance from the first radiation beam in response to an offset signal. The offset signal is generated by optically measuring the distance between a pair of calibration tracks that have previously been placed on the disk so as to have the desired track pitch therebetween. The effect of variations or drift occurring in the optical or electrical components of either the write alignment servo or the optical track pitch measurement system is significantly reduced by regularly calibrating against the fixed track pitch of the calibration tracks.

Abstract: A centering mechanism for centering the disk recording medium over the spindle of a rotating disk storage system is presented. The invention consists of a centerpiece in the disk having three or more fingers pointing in the direction of insertion and curved away from the center of the disk. As the disk is inserted over a tapered spindle, one side or the other of the fingers will contact the spindle and center the disk as it moves toward the tapered spindle. The bottom edge of the center hole of the disk is rounded to form a stop for the fingers. The fingers bend as the disk is inserted, and this stop ensures that the fingers will not bend too far and break. When the disk is fully inserted, all the fingers around the circumference of the hole are contacting the tapered spindle hub and are also bent back against the stop surface on the disk to provide good centering.

Abstract: A flexible hub for a disk is described. The disk includes a relatively large center hole into which a flexible planar member is mounted or clamped. The size of the flexible member is slightly larger than the hole, thereby requiring that the flexible member be slightly bowed or flexed in order for it to fit within the hole. The flexible member is preferably attached to the disk at three respective equi-angularly spaced locations around the periphery of the hole. In the center of the flexible member is a collar adapted to receive a protruding spindle neck from a spindle mechanism upon which the disk is mounted. The end of the spindle neck and the inside wall of the collar are tapered at the same angle. Insertion of the spindle neck into the collar thereby forces alignment or centering of the center of the collar with the longitudinal axis of the spindle neck.

Abstract: The centering and clamping device consisting: a disk elevator, a disk support, a disk centering assembly, a disk clamping assembly, and a disk rotating assembly. In operation the disk is raised out of the disk insert tray cartridge by the disk elevating means and raised upward to engage a taper on the spindle of the device spin motor, moving upward until the cooperation between the taper on the neck spindle and the tapering on the disk centering collar cause the disk to move laterally until precisely centered on the spindle. Thereafter, the continued upward movement on the disk on the elevator lifting assembly causes a magnet located on the disk support means to come into magnetic contact with a steel plate on the spindle platform, thereby securely clamping the disk to the spindle for rotation. Thereafter, the elevator moved downward and clamping the disk from disk support means, thereby allowing the free rotation of the spindle disk and disk support assembly relative to a stationary elevating means.

Abstract: A disk drive control circuit designed to eliminate undesirable mechanical resonances that occassionally occur in the disk drive system as a result of a particular combination of seek commands. The control circuit uses an electrical model of the mechanical system in order to estimate or predict whether a particular seek command is likely to excite a mechanical resonance. The electrical model may be a filter network having frequency response characteristics similar to the mechanical system. The current used to drive a linear motor of the mechanical system is then applied to the filter network. The signal output from the filter network, which network effectively models the mechanical system, is thus representative of the mechanical response of the system upon performance of the seek operation. This signal output is monitored, and if it exceeds a predetermined threshold level, steps are taken to alter the system response so as to avoid exciting the mechanical resonance.