Andrew Thomas Rose

45569215, Dec 3, 1985

Jun 30, 1983

6/509841

Andrew M. Rose - Mountain View CA

Memorex Corporation - Santa Clara CA

G11B 2110
G11B 2108

360 77

An apparatus to improve the positioning accuracy of an actuator in a disc system. The apparatus provides for accelerating and braking the actuator at appropriate times during positioning operations in order to accurately position the actuator at a selected track on the disc. In addition, in order to maintain positioning accuracy in the presence of run-out, provision is made for detecting the occurrence of run-out by comparing positioning accuracy at spaced time intervals and blocking actuator braking at those times when it would be counter-productive to positioning accuracy.

43778275, Mar 22, 1983

Nov 10, 1980

6/205680

Andrew M. Rose - Mountain View CA

Memorex Corporation - Santa Clara CA

G11B 2110

360 78

A servo system in a disc drive for accessing and maintaining selected data tracks on a stack of discs has a first continuous position signal derived from a pre-recorded surface and a second position signal derived from servo information in sectors of the other discs. The first and second position signals are combined to form a hybrid signal to control the actuators. The hybrid signal is the second signal when the second signal is generated. When the second signal is not generated, the hybrid signal is a modified first signal plus the last known second signal. The modified first signal is the difference between the first signal presently generated and the first signal generated when the second signal was last generated.

58779108, Mar 2, 1999

Jun 3, 1994

8/253618

Roger O. Williams - Fremont CA
Jimmy D. Godwin - San Jose CA
Stephen P. Williams - San Jose CA
Mark E. Strysko - San Jose CA
Alton B. Otis - San Francisco CA
Andrew M. Rose - Mountain View CA

Insite Peripherals, Inc. - Boulder CO

G11B 5596

360 66

A dual magnetic head having a first magnetic core for reading and writing very high track density floppy disks and a second magnetic core for reading and writing conventional track density floppy disks. Neither the first nor the second magnetic cores require the trim erase elements associated with prior art magnetic cores for use with floppy disks. When writing on conventional track density floppy disks, separation between data tracks is achieved by erasing a circular region on a first rotation of the floppy disk, erasing a second region, separated from the first region by a small gap, on a second rotation of the floppy disk, and writing data during a third rotation of the floppy disk centered about the small gap. With very high density floppy disks, data is written directly between optical servo tracks on the floppy disk without use of the two erase steps.

42636272, Apr 21, 1981

Jun 18, 1979

6/049247

Andrew M. Rose - Mountain View CA
James J. Touchton - Boulder CO

Sperry Rand Corporation - New York NY

G11B 2110
G11B 1914
G11B 554

360 75

An electronic tachometer that includes an integrator for producing a speed signal by integrating a signal representative of acceleration of a body and a differentiator for producing a speed signal by differentiating a signal representative of the position of the body, the differentiator being formed by a passive RC circuit and operatively associated with circuitry for alternately supplying to the differentiator two signals representative of position, one of which is inverted so that signals of a single polarity are supplied to the differentiator, and further circuitry for connecting the differentiator output to the integrator feedback circuitry so as periodically to update or reset the speed signal produced by the integrator, which is formed by an operational amplifier having a capacitive feedback which is shunted by a resistor when the differentiator output is active to update the integrator.

49891030, Jan 29, 1991

Feb 20, 1990

7/483975

Nicholas M. Warner - Livermore CA
Andrew M. Rose - Mountain View CA

Unisys Corp. - Detroit MI

G11B 502

360 67

In a disk drive servo, position slope is adjusted automatically, by referencing on the amplitude of position signals at the "half-track point".

41684575, Sep 18, 1979

Dec 29, 1977

5/865472

Andrew M. Rose - Mountain View CA

Sperry Rand Corporation - New York NY

G05B 1300

318561

Apparatus for controlling the velocity of a moveable load, such as the magnetic head assembly of a disk drive, comprising means for providing velocity command and velocity feedback signals which are combined to produce a velocity control signal for moving the load at desired velocity and additional means including an integrator and sample and hold circuit for detecting error in the feedback signal and varying the command signal to compensate for such error so that the load is controlled to move at the desired velocity.

52414310, Aug 31, 1993

Sep 14, 1990

7/569876

Nicholas M. Warner - Livermore CA
Andrew M. Rose - Mountain View CA

Unisys Corporation - Blue Bell PA

G11B 502

360 67

In a disk drive servo, position slope is adjusted automatically, by referencing on the amplitude of position signals at the "half-track point".

42850150, Aug 18, 1981

Dec 10, 1979

6/102304

Andrew M. Rose - Mountain View CA
Frank J. Sordello - Los Gatos CA
James J. Touchton - Boulder CO

Sperry Corporation - New York NY

G11B 2108

360 78

As an aid in counting servo tracks in a position servo system, a position window detector (30) which normally provides coarse and fine pulses to counting logic (53) also provides fine pulses to a reset switch (45) of a tachometer signal integrator means (33), resetting the integrator once for each track. In the event of position signal drop-out wherein coarse pulses are not properly generated, a threshold detection means (43) senses when the output of the integrator reaches a threshold level and produces a threshold reached signal which is transmitted to counting logic means (53) for incrementing a track counter (61).