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US 6,212,027 B1Granted
Stable unlatch control of hard disk drive
AssigneeSamsung Electronics Co., Ltd.
InventorsJung-Ho Lee, Gwan-Il Kim
Life of this patent
Estimating the term…
Abstract
An unlatch control technique for enabling a hard disk drive to perform well a following sequence with a stable speed of a head being maintained after a head is unlatched by adjusting an unlatching deceleration current includes the steps of: detecting servo information written in a sector on a predetermined track of a disk when controlling the unlatching operation of the head; calculating the speed of the head which is unlatched by using the servo information; and adjusting the unlatching current depending on the head speed. Since the unlatching current can be adjusted through the feedback process of the head speed in the control of the unlatching operation, a more stable unlatching operation is accomplished.
Claims38
A method of controlling the unlatching operation of a head in a hard disk drive, comprising the steps of:
- detecting servo information written in a sector on a predetermined track of a disk having a plurality of tracks when controlling the unlatching operation of said head, said servo information comprising information stored within each of said tracks;
- calculating said head speed of the head which is unlatched by using said servo information according to the following formula:
- the head speed = ΔTrack T = a previous gray code - a present gray code T
- where, T=servo sampling period and
- ΔTrack=a distance between the previous track and the present track;
- and
- adjusting an unlatching current depending on said head speed.
4 more elements
A method of controlling unlatching of a head in a hard disk drive, comprising the steps of:
- detecting servo information written in a plurality of sectors on a plurality of tracks of a disk within said hard disk drive when controlling said unlatching of said head, with said servo information uniquely identifying a radial position of each track within an incrementally ordered serial array of said plurality of tracks borne by said disk, by reading said servo information from among said sectors within a data zone bearing a multiplicity of said tracks, from among said sectors within an inner-guard band zone circumferentially interposed between said data zone and a parking zone of said disk where said head rests while an armature bearing said head is held stationary, and from among said sectors within an outer-guard band zone that separates said data zone from an outer peripheral edge of said disk;
- and
- making a determination of head speed of the head by using said servo information;
- and adjusting an unlatching current in dependence upon said determination of head speed.
1 more element
A method of controlling an unlatching of ahead in a hard disk drive, comprising the steps of:
- detecting servo information written in a sector on a predetermined track of a disk having a plurality of tracks when controlling the unlatching of said head;
- calculating said head speed of the head which is unlatched by using said servo information;
- and
- at a deceleration edge of said head speed, adjusting an unlatching current being applied during said unlatching of the head in dependence upon said head speed.
1 more element
A method of controlling the unlatching operation of a head in a hard disk drive, comprising the steps of:
- supplying a forward unlatching current of a uniform size to an actuator on which said head is mounted during a regular time interval for unlatching said head;
- accelerating the speed of said head;
- supplying a reverse unlatching current of a uniform size to said actuator only during a predetermined time interval for deceleration control of said head after an established time has passed;
- decelerating said head speed at an initial stage;
- searching periodically servo information written in a sector on a predetermined track of a disk having a plurality of tracks;
- detecting information on each track in said servo information;
- calculating said head speed by using said information on each of said tracks;
- decrementing gradually said reverse unlatching current by a predetermined brake current value if a value of said head speed is greater than the predetermined head speed limit value;
- and
- supplying said decremented reverse unlatching current to said actuator.
7 more elements
An apparatus for controlling the unlatching operation of a head in a hard disk drive, comprising:
- a detector for detecting servo information written in a sector on a disk having a plurality of tracks when controlling the unlatching operation of said head by detecting servo information written in a plurality of sectors on a plurality of tracks of a disk within said hard disk drive when controlling said unlatching of said head, with said servo information uniquely identifying a radial position of each track within an incrementally ordered serial array of said plurality of tracks borne by said disk, by reading said servo information from among said sectors within a data zone bearing a multiplicity of said tracks, from among said sectors within an inner-guard band zone circumferentially interposed between said data zone and a parking zone of said disk where said head rests while an armature bearing said head is held stationary and from among said sectors within an outer-guard band zone that separates said data zone from an outer peripheral edge of said disk;
- and
- a controller making a determination of a head speed of the head which is unlatched, by using said servo information, and periodically adjusting an unlatching current in dependence upon said head speed determined by using said servo information.
An apparatus for controlling the unlatching operation of a head in a hard disk drive, comprising:
- a current source for supplying a forward unlatching current of a uniform size to an actuator on which said head is mounted during a regular time interval for unlatching said head;
- a means for accelerating the speed of said head;
- said current source supplying a reverse unlatching current of a uniform size to said actuator only during a predetermined time interval for deceleration control of said head after an established time has passed;
- a means for decelerating said head speed at an initial stage;
- a detector for searching periodically servo information written in a sector on a predetermined track of a disk having a plurality of tracks and for detecting information on each track in said servo information;
- a calculator for calculating said head speed using said detected information on each of said tracks;
- said current source decrementing gradually said reverse unlatching current by a predetermined brake current value if a value of said head speed is greater than the predetermined head speed limit value;
- and
- said current source supplying said decremented reverse unlatching current to said actuator.
6 more elements
A process for controlling an unlatching operation of a head in a hard disk drive, comprising the steps of:
- detecting servo information written in a plurality of sectors on a plurality of tracks of a disk within said hard disk drive when controlling unlatching of said head, with said servo information uniquely identifying a radial position of each track within an incrementally ordered serial array of said plurality of tracks borne by said disk;
- making a determination of head speed of said head relative to said disk by using said servo information;
- and
- adjusting an unlatching current in dependence upon said determination of head speed.
1 more element
A process for controlling an unlatching operation of a head in a hard disk drive, comprising the steps of:
- unlatching said head by applying an unlatching current exhibiting a first amplitude and a first polarity to move an armature bearing said head from a parking zone on the disk where said head rests while said armature is held stationary;
- altering said unlatching current to provide a deceleration component exhibiting a second and opposite polarity;
- detecting servo information written in a plurality of sectors on a plurality of tracks of the disk within said hard disk drive when controlling said unlatching of said head, with said servo information comprising gray codes uniquely identifying a radial position of each track within an incrementally ordered serial array of said plurality of tracks borne by said disk;
- making a determination of head speed of said head relative to said disk by using said servo information;
- and
- modifying said deceleration component of said unlatching current in dependence upon said determination of head speed.
3 more elements
A process for controlling an unlatching of a head in a hard disk drive, comprising the steps of:
- while controlling said unlatching of said head, detecting servo information comprising servo synchronization stored in a plurality of sectors on a plurality of tracks borne by a disk within said hard disk drive, with said servo synchronization providing a clock synchronization during reading of said servo information and identifying preambles of each of said sectors of said plurality of tracks;
- making a determination of whether said servo synchronization has been read by said head;
- making a determination of head speed of said head relative to said disk by using said servo information;
- and
- varying said head speed of said head relative to said disk by adjusting an unlatching current in dependence upon said determination of whether said servo synchronization has been read by said head and in dependence upon said determination of said head speed.
2 more elements
A process for controlling an unlatching operation of a head in a hard disk drive, comprising the steps of:
- controlling unlatching of said head by applying an unlatching current exhibiting a first polarity to move an armature bearing said head from a parking zone on the disk where said head rests while said armature is held stationary;
- altering said unlatching current to provide a deceleration component exhibiting a second and opposite polarity;
- while controlling unlatching of said head, detecting servo information comprising servo synchronization stored in a plurality of sectors on a plurality of tracks borne by a disk within said hard disk drive, with said servo synchronization providing a clock synchronization during reading of said servo information and identifying preambles of each of said sectors of said plurality of tracks;
- making a determination of whether said servo synchronization has been read by said head;
- and
- varying a head speed of said head relative to said disk by adjusting said deceleration component of said unlatching current in dependence upon said determination.
3 more elements
Dependencies are inferred from the claim text.