Guzik Technical Enterprises

Vss Monitoring, Inc.

Ilia M Bokchtein

Ufuk Karaaslan

Nahum E Guzik

Anatoli B Stein

James Crim

Alexander Varlakhanov

Cem Kilicci

An electronic equipment chassis assembly includes a housing, and a plurality of openings defined in the housing that allow airflow there-through. The openings include at least one intake opening defined in the front surface of the housing and at least one exit opening defined in the rear surface of the housing. The chassis also includes an air filter, and one or more rails disposed within the housing defining receiving slots that releasably secure a first plurality of circuit boards, and a second plurality of circuit boards, which second plurality of circuit boards are orthogonally oriented relative to the first plurality of circuit boards. The chassis includes an airflow assembly proximate the top surface of the housing, and one or more output fans proximate the rear surface of the housing. The airflow assembly and the output fans balance airflow throughout the chassis.

Cooling architecture for a chassis with orthogonal connector system

A read channel network of a magnetic data storage device receives analog signals representative of user data and servo data, wherein the servo data is usable to position a read/write magnetic head. The servo data is separately processed within the read channel network to improve the signal to noise ratio of the user data signal and, thereby, permit improved positioning accuracy of the read/write head within the magnetic data storage device. The servo signal applied to a multiplier along with an oscillating signal reference signal to produce a sideband signal, which is passed through a bandpass filter having a bandwidth about that of the sideband signal and having a center frequency substantially the same as that of the sideband signal. Additionally, the signal output by the bandpass filter is processed by an envelope detector, and then by an A/D converter and digital filter to produce a digital signal representative of the servo signal.

Method and apparatus for improved servo signal filtering in read channels

A magnetic head and disk tester includes a magnetic head which is selectively positioned relative to a rotatably mounted magnetic disk to accomplish testing of either of the head or disk or both. The magnetic head is secured to a carriage which is under electro-mechanical control, wherein displacement of the carriage causes a corresponding displacement of the head relative to the disk and, to some degree, may cause yaw in the carriage. Measurements of the linear position of a left and a right side of the carriage are detected, measured, and fed back to a control system. The control system responds to a difference between a desired command position and the actual position of each side of the carriage and causes actuators to adjust the position of each side of the carriage until the difference, and thereby the yaw, is substantially eliminated. Additionally, during a positioning operation, vibrations in the yaw direction are decreased, which decreases a corresponding settling time of the magnetic head.

Magnetic head and disk tester with yaw correction

An apparatus for balancing the spinstand of a magnetic head and disk testing system includes a base that rotationally supports a rotating spindle. The spindle supports a pack of disks and a slide moveable along guide rails of the spinstand. The slide, in turn, supports a stack of magnetic heads that is moveable in respect to the pack of disks. The spindle supports a balancing cap that has a plurality of threaded openings uniformly spaced in its peripheral surface. Imbalance is adjusted by threading screws into or out of the selected threaded openings. The value of imbalance is defined by vibration measurements; these measurements are performed by means of an accelerometer attached to the spindle housing, and of a rotary encoder that generates index pulse in a certain position of the spindle. In order to provide reliable measurements by means of the accelerometer, the spindle housing either can be fixed to test magnetic heads, or can be turned to a spring-loaded condition to increase sensitivity of the balancing procedure. Each time the disk pack is replaced, the system measures the amount of radial displacement of the screws in respective openings that is necessary to compensate the imbalance created by the new disk pack. The proposed balancing method includes manual or automated calibration procedure, automatic vibration measurements, and manual adjustment of the positions of screws in the balancing cap using the results of measurements.

Method and apparatus for balancing rotating components of a spinstand of

The head/disk tester of the invention has a housing 43 that houses spindle 44 that rotatingly supports a magnetic disk 31. The housing supports a moveable carriage 30 that, in turn, supports a magnetic head 32. Positioning means 39 and 41 are used to move the carriage and the magnetic head across the magnetic disk. These positioning means include stepper motors that realize coarse positioning of the magnetic head, and a piezo actuator 37 that is used for fine positioning. Linear encoders 40 and 42 located at both sides of the carriage provide feedback information to a closed-loop positioning system that controls the piezo actuator. A set of special signals ('servo bursts') pre-written at a given track of the magnetic disk is used as an additional source of feedback information for the same closed-loop positioning system. This positioning system includes a servo analyzer 45 that reads and processes servo burst signals from the magnetic disk, and a position controller 49 that controls the piezo actuator. The controller contains two control loops: a proportional-integral-derivative (PID) loop and an additional servo burst loop. During any movement of the magnetic head to a prescribed command position, the servo burst feedback is turned off, and feedback from linear encoders is used by the PID loop to move the head. When the magnetic head reaches the prescribed command position, servo burst loop is turned on; it changes the command position of the PID loop in a way to keep the ratio of pre-written burst signals constant. As a result, the position of the magnetic head with respect to the data track remains the same for as long as necessary, even in unstable temperature conditions.

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Santa Clara, CA, United States of America

Ilia M Bokchtein