US5455724A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of compensating offtrack in disk unit
Assignee: Toshiba Storage Device Corp
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Filing: 1993-02-26
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Granted: 1995-10-03
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Expires: 2013-02-26
Abstract
Abstract In a disk unit including a plurality of disk media of which any one surface is a servo surface and the other surfaces are all data surfaces; a servo head and data heads arranged on the servo surface and the data surfaces; a positioning mechanism for positioning the servo head and the data heads on desired tracks; and a control unit for controlling the positioning mechanism; the control unit reading servo data from the data surfaces and updates them to find offtrack compensated data, and the head positioning operation being controlled by using the offtrack compensated data and servo information on the servo surface, an offset occurring in the disk unit is compensated by setting the servo track center of the servo head as a reference for positioning the head; writing a pair of servo data for positioning the head onto said data surface while giving a predetermined offset amount which is offset from said track center; giving a predetermined offset amount to thus read and measure the pair of servo data and using the measured value to determine a conversion coefficient; and effecting an offtrack compensation with respect to an offtrack amount detected based on the pair of servo data, by means of a value that is calibrated using the conversion coefficient. By the method, it is possible to accurately effect the offtrack compensation, shorten the time required for measuring the offtrack amount, and improve a reliability of the disk unit.
Inventors
- 👤 Nobuyuki Suzuki
- 👤 Syuichi Hashimoto
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 20:35
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/48; G11B5/58; G11B5/596; G11B5/54; G11B5/55; G11B5/5521; G11B5/5526; G11B5/553; G11B5/5534
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
256 words
A method of compensating an offtrack in a disk unit having a plurality of disk media each having a servo surface and data surfaces, a servo head and data heads arranged on said servo surface and said data surfaces, respectively, a positioning mechanism for positioning the servo head and the data heads on desired tracks, and a control unit for controlling said positioning mechanism, wherein said control unit reads servo data from the data surfaces and updates them to find offtrack compensated data, and the head positioning mechanism is controlled by using the offtrack compensated data and servo information of the servo surface, the method comprising the steps of: setting the servo tracking center of the servo head as a reference for positioning the head; writing a pair of servo data for positioning the head onto said data surface including data giving a predetermined offset amount which is offset from said servo tracking center; employing a predetermined offset amount to read and measure the pair of servo data; determining a conversion coefficient using the measured value; and effecting an offtrack compensation with respect to an offtrack amount detected based on the pair of servo data, through use of a value that is calibrated using the conversion coefficient, wherein said conversion coefficient is represented by a ratio of an offset amount that is determined at the time of reading during a procedure to find said conversion coeffictient, the pair of servo data to a real offtrack amount that is measured by reading the pair of servo data.
Claim 2
Independent Claim
256 words
A method of compensating an offtrack in a disk unit having a plurality of disk media each having a servo surface and data surfaces, a servo head and data heads arranged on said servo surface and said data surfaces, respectively, a positioning mechanism for positioning the servo head and the data heads on desired tracks, and a control unit for controlling said positioning mechanism, wherein said control unit reads servo data from the data surfaces and updates them to find offtrack compensated data, and the head positioning mechanism is controlled by using the offtrack compensated data and servo information of the servo surface, the method comprising the steps of: setting the servo tracking center of the servo head as a reference for positioning the head; writing a pair of servo data for positioning the head onto said data surface including data giving a predetermined offset amount which is offset from said servo tracking center; employing a predetermined offset amount to read and measure the pair of servo data; determining a conversion coefficient using the measured value; and effecting an offtrack compensation with respect to an offtrack amount detected based on the pair of servo data, through use of a value that is calibrated using the conversion coefficient, wherein said conversion coefficient is represented by a ratio of an offset amount that is determined at the time of reading during a procedure to find said conversion coeffictient, the pair of servo data to a real offtrack amount that is measured by reading the pair of servo data.
Claim 3
Dependent Claim
17 words
The method according to claim 1, wherein said pair of servo data include a set of data.
Claim 4
Dependent Claim
31 words
The method according to claim 2, wherein said pair of servo data are written on both sides of said servo tracking center giving an equal offset amount to said both sides.
Claim 5
Dependent Claim
41 words
The method according to claim 3, wherein said conversion coefficient is determined by giving an equal offset amount to both sides of said servo tracking center and reading the pair of servo data at positions corresponding to the predetermined offset amount.
Claim 6
Dependent Claim
53 words
The method according to claim 4, wherein said conversion coefficient is determined by reading and measuring a pair of servo data for each of the positions that correspond to offset amounts to find a difference;in the values of the offtracks, and then by determining a practical offtrack amount from the value of error.
Claim 7
Dependent Claim
61 words
The method according to claim 2, wherein when the offset amount or the value of servo data and the real offtrack amount of the head are not on a linear relationship, the amount is divided into such small sections that said relationship can be sufficiently regarded to be a linear one, and conversion coefficients are determined for each of the sections.
Claim 8
Dependent Claim
35 words
The method according to claim 1, wherein said conversion coefficient is stored in a non-volatile memory, and the offtrack compensated data is calibrated by using the conversion coefficient that is read from said non-volatile memory.
Claim 9
Dependent Claim
51 words
The method according to claim 1, wherein the offtrack amount detected from said pair of servo data is compensated by a value that is obtained by subtracting a position control error at the time when the offtrack amount is detected, from a value that is calibrated by using said conversion coefficient.
Claim 10
Dependent Claim
19 words
The method according to claim 1, wherein the pair of servo data includes a plurality of sets of data.
Claim 11
Dependent Claim
57 words
The method according to claim 9, wherein said pairs of servo data are written in a manner that the pair of data of a given set are written on both sides of the tracking center and the servo data of other sets are written about positions which are remote by predetermined amounts from said servo tracking center.
Claim 12
Dependent Claim
39 words
The method according to claim 10, wherein the conversion coefficients are found for each of the sets of servo data by reading and measuring pairs of servo data while giving a predetermined offset amount for each of the sets.
Claim 13
Dependent Claim
46 words
The method according to claim 11, wherein the pair of servo data of a given set are read and measured out of said sets, and a conversion coefficient found from these values is used as a representative value for the plurality of sets of servo data.
Claim 14
Dependent Claim
31 words
The method according to claim 1, wherein processing for determining said conversion coefficient is carried out during the fabrication of the disk unit or during the adjustment thereof before the shipment.
Claim 15
Dependent Claim
25 words
The method according to claim 1, wherein processing for determining said conversion coefficient is carried out at a place of a user after the shipment.
Claim 16
Dependent Claim
33 words
The method according to claim 14, wherein processing for determining the conversion coefficient is carried out when the combination of a mechanical unit and a control unit of the disk unit is changed.
Claim 17
Dependent Claim
27 words
The method according to claim 1, wherein the offtrack is compensated after every given period of time by using a value calibrated by using the conversion coefficient.
Claim 18
Dependent Claim
37 words
The method according to claim 1, wherein the temperature of the disk unit is measured, and the offtrack is compensated by using a value calibrated by using said conversion coefficient under the condition of the measured temperature.
Claim 19
Dependent Claim
42 words
The method according to claim 1, wherein error is monitored while the disk unit is in operation to produce error information, and the offtrack is compensated by using a value calibrated by using said conversion coefficient by means of said error information.
Claim 20
Independent Claim
274 words
A method of compensating an offtrack in a disk unit having a plurality of disk media each having a servo surface and data surfaces, a servo head and data heads arranged on said servo surface and said data surfaces, respectively, a positioning mechanism for positioning the servo head and the data heads on desired tracks, and a control unit for controlling said positioning mechanism, wherein said control unit reads servo data from the data surfaces and updates them to find offtrack compensated data, and the head positioning mechanism is controlled by using the offtrack compensated data and servo information of the servo surface, the method comprising the steps of: setting the servo tracking center of the servo head as a reference for positioning the head; writing a pair of servo data for positioning the head onto said data surface including data giving a predetermined offset amount which is offset from said servo tracking center; employing a predetermined offset amount to read and measure the pair of servo data; determining a conversion coefficient using the measured value; and effecting an offtrack compensation with respect to an offtrack amount detected based on the pair of servo data, through use of a value that is calibrated using the conversion coefficient, wherein said pair of servo data include a set of data and are written on both sides of said servo tracking center giving an equal offset amount to said both sides, and wherein said conversion coefficient is determined by giving an equal offset amount to both sides of said servo tracking center and reading the pair of servo data at positions corresponding to the predetermined offset amount.
Claim 21
Independent Claim
274 words
A method of compensating an offtrack in a disk unit having a plurality of disk media each having a servo surface and data surfaces, a servo head and data heads arranged on said servo surface and said data surfaces, respectively, a positioning mechanism for positioning the servo head and the data heads on desired tracks, and a control unit for controlling said positioning mechanism, wherein said control unit reads servo data from the data surfaces and updates them to find offtrack compensated data, and the head positioning mechanism is controlled by using the offtrack compensated data and servo information of the servo surface, the method comprising the steps of: setting the servo tracking center of the servo head as a reference for positioning the head; writing a pair of servo data for positioning the head onto said data surface including data giving a predetermined offset amount which is offset from said servo tracking center; employing a predetermined offset amount to read and measure the pair of servo data; determining a conversion coefficient using the measured value; and effecting an offtrack compensation with respect to an offtrack amount detected based on the pair of servo data, through use of a value that is calibrated using the conversion coefficient, wherein said pair of servo data include a set of data and are written on both sides of said servo tracking center giving an equal offset amount to said both sides, and wherein said conversion coefficient is determined by giving an equal offset amount to both sides of said servo tracking center and reading the pair of servo data at positions corresponding to the predetermined offset amount.
Claim 22
Dependent Claim
54 words
The method according to claim 19, wherein said conversion coefficient is determined by reading and measuring a pair of servo data for each of the positions that correspond to offset amounts to find a difference in the values of the offtracks, and then by determining a practical offtrack amount from the value of error.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1998-10-02 | 1999-04-03 | 1999-10-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2002-10-02 | 2003-04-03 | 2003-10-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2006-10-02 | 2007-04-03 | 2007-10-03 | $7700.00 | Window Closed / Lapsed |