Browse Prior Art Database

Disk Acceleration/Slider Takeoff Plotter

IP.com Disclosure Number: IPCOM000120472D
Original Publication Date: 1991-Apr-01
Included in the Prior Art Database: 2005-Apr-02
Document File: 1 page(s) / 60K

Publishing Venue

IBM

Related People

Butturf, RL: AUTHOR [+3]

Abstract

Described is an instrument which allows the angular speed and acceleration of a hard disk drive spindle to be plotted as a function of time. Additionally, these measurements can be displayed versus the same time axis as a head takeoff signal in order to determine at what speed the recording head leaves or lands on the disk surface. The instrument can also be combined with a gateable counter in order to determine the number of sliding revolutions the head disk interface undergoes at either start up or power down. This instrument is useful for measuring head takeoff speeds in the drive, for measuring the spindle acceleration profile and for measuring the number of sliding revolutions at both power on and power off.

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Disk Acceleration/Slider Takeoff Plotter

      Described is an instrument which allows the angular speed and
acceleration of a hard disk drive spindle to be plotted as a function
of time.  Additionally, these measurements can be displayed versus
the same time axis as a head takeoff signal in order to determine at
what speed the recording head leaves or lands on the disk surface.
The instrument can also be combined with a gateable counter in order
to determine the number of sliding revolutions the head disk
interface undergoes at either start up or power down.  This
instrument is useful for measuring head takeoff speeds in the drive,
for measuring the spindle acceleration profile and for measuring the
number of sliding revolutions at both power on and power off.

      See the figure for a block diagram of the instrument. The
configuration shown in the diagram allows the head takeoff signal to
be plotted along with the spindle speed versus time.  This plot
provides a means of measuring the angular speed at which the slider
leaves or lands on the disk.

      This instrument operates by converting a series of rotational
pulses into an angular speed signal.  The angular speed is
represented by an analog voltage which can be displayed versus the
same time axis as the output signal from an ultrasonic probe.  The
preferred disk pulse generator consists of a photonic probe which
senses the presence of reflective tape on the spindle hub.  The
output from the photo...