Inventor
FENNEMA ALAN A
US30 patents
⚠️ This page may combine multiple inventors who share the name “FENNEMA ALAN A”. Patents are grouped by organization below to help distinguish them — per-person disambiguation is on the roadmap.
IBM
21 patentsUS5499231AMar 12, 1996
Optical disk drive with multiple data layer disk and system for focusing the optical beam
IBM56 citations96
US5136569AAug 4, 1992
Optical disk recorder for diverse media types and having a predetermined initialization or start-up procedure
IBM70 citations96
US5060210AOct 22, 1991
Controlling head seeking speed in disk storage units by limiting displacement of head with respect to its supporting headarm
IBM57 citations96
US5038333AAug 6, 1991
Positioning systems including reliable track crossing detection for high speed relative motions
IBM59 citations94
US5220546AJun 15, 1993
Operating optical disk drives including calibrating a tracking error signal
IBM35 citations92
US4839876AJun 13, 1989
Track seeking using a track following loop
IBM35 citations92
US5134602AJul 28, 1992
Calibrating optical disk recorders to some parameters during disk spin up while deferring calibration of other parameters
IBM32 citations91
US5090002AFeb 18, 1992
Positioning systems employing velocity and position control loops with position control loop having an extended range
IBM22 citations91
US5426625AJun 20, 1995
Masking of tracking error signal abnormalities due to media defects
IBM36 citations90
US5138594AAug 11, 1992
Reducing amplitude variations of optical disk readback signals and increasing reliability of track-crossing counts
IBM42 citations90
US5164932ANov 17, 1992
Acquiring a best focus using a focus signal offset
IBM32 citations89
US4519553AMay 28, 1985
Multiple spindle winding apparatus
IBM20 citations78
US5142516AAug 25, 1992
Anti-skating control of a positioning servo system
IBM16 citations74
US5425013AJun 13, 1995
Relative position sensing calibration for optical storage device
IBM18 citations73
US5046060ASep 3, 1991
Servo error controls
IBM18 citations73
US5097361AMar 17, 1992
Controlling position of a rotatable transducer in devices employing such transducers
IBM7 citations72
US4998233AMar 5, 1991
Acquiring focus in optical systems using a focus error signal and a laser drive signal
IBM19 citations69
US5257251AOct 26, 1993
Single loop servo-positioning systems having means for changing the dynamic range of a position-error signal with speed of the relatively movable members
IBM9 citations66
US5128913AJul 7, 1992
Acquiring focus in an optical system using a soft focus acquiring system
IBM3 citations61
US5233585AAug 3, 1993
Acquiring focus in an optical disk system using a time and shape modified focus error signal
IBM4 citations60
US5289319AFeb 22, 1994
Apparatus and method for detecting physical orientation of a position system and for calibrating an optimum control for the system that is usable in optical disk recorders
IBM1 citations46
SEAGATE TECHNOLOGY LLC
3 patentsUS6785075B2Aug 31, 2004
Self-writing servo and clock fields on a recording medium
SEAGATE TECHNOLOGY LLC41 citations92
US6898038B1May 24, 2005
Method and apparatus for disc drive data security using fields in servo wedges
SEAGATE TECHNOLOGY LLC15 citations84
US7518816B2Apr 14, 2009
Method and apparatus for disc drive data security using fields in servo wedges
SEAGATE TECHNOLOGY LLC2 citations63