US4424543A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method and apparatus for recording transducer positioning information
Assignee: DMA Systems Corp
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Filing: 1981-11-16
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Granted: 1984-01-03
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Expires: 2001-11-16
Abstract
Abstract In a magnetic disc storage system and a magnetic disc therefor, the disc having opposed surfaces, at least one of the surfaces being coated with a magnetic material, the disc being adapted to be mounted on a spindle for rotation relative to a magnetic transducer positioned for recording data on and retrieving data from the disc, a plurality of concentric annular tracks being defined on the surface of the disc, each of the tracks being divided into a plurality of sectors, each sector having associated therewith prerecorded servo data for identification thereof, the improvement wherein the servo data for each sector comprises a unit distance track identification code recorded three times in succession, the code changing between adjacent sectors of adjacent tracks, and a clock shift check code recorded immediately following the last recorded one of the track identification codes, the same clock shift check code being recorded for each sector of every track.
Inventors
- 👤 Martyn A. Lewis
- 👤 Steven K. Penniman
- 👤 David A. Sutton
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 06:29
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/48; G11B5/58; G11B5/596; G11B5/59633; G11B5/59655
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
142 words
In a disc having opposed surfaces, at least one of said surfaces being coated with a magnetic material, said disc being adapted to be mounted on a spindle for rotation relative to a magnetic transducer positioned for recording data on and reading data from said surface, a plurality of concentric annular tracks being defined on said surface of said disc, each of said tracks being divided into a plurality of sectors, each such sector having associated therewith prerecorded data for identification thereof, the improvement wherein said prerecorded identification data comprises: a track identification code recorded a plurality of times in succession, said code changing between adjacent sectors in adjacent tracks; and a clock shift check code recorded immediately following the last recorded one of said track identification codes, the same clock shift check code being recorded for each sector of every track.
Claim 2
Dependent Claim
142 words
In a disc having opposed surfaces, at least one of said surfaces being coated with a magnetic material, said disc being adapted to be mounted on a spindle for rotation relative to a magnetic transducer positioned for recording data on and reading data from said surface, a plurality of concentric annular tracks being defined on said surface of said disc, each of said tracks being divided into a plurality of sectors, each such sector having associated therewith prerecorded data for identification thereof, the improvement wherein said prerecorded identification data comprises: a track identification code recorded a plurality of times in succession, said code changing between adjacent sectors in adjacent tracks; and a clock shift check code recorded immediately following the last recorded one of said track identification codes, the same clock shift check code being recorded for each sector of every track.
Claim 3
Dependent Claim
19 words
In a disc according to claim 1, the improvement wherein said track identification code is a unit distance code.
Claim 4
Dependent Claim
21 words
In a disc according to claim 1, the improvement wherein said track identification code is recorded in a Gray code format.
Claim 5
Dependent Claim
21 words
In a disc according to claim 1, 2 or 3, the improvement wherein said track identification code is recorded three times.
Claim 6
Dependent Claim
39 words
In a disc according to claim 1 or 2, the improvement wherein said clock shift check code consists of a plurality of bits of data wherein said bits of data are the same for each sector of every track.
Claim 7
Dependent Claim
57 words
In a disc according to claim 1 or 2, the improvement wherein said prerecorded identification data for each sector further comprises: a pair of bursts of high density transitions recorded following each check code and further recorded so as to equally overlap adjacent tracks and being offset in time for the purpose of providing fine position information.
Claim 8
Dependent Claim
46 words
In a disc according to claim 6, the improvement wherein said bursts of high density transitions are recorded so that when said magnetic transducer is aligned with a track, the amplitude of the signal received by said transducer from the bursts of each pair are equal.
Claim 9
Dependent Claim
69 words
In a disc according to claim 6, the improvement wherein said prerecorded identification data for each sector further comprises: a fully DC erased gap for providing initial time synchronization; and a predetermined pattern of data bits recorded following each DC erased gap for providing clock synchronization, said predetermined pattern being recorded for each sector and for each track, said track identification code following said predetermined pattern of data bits.
Claim 10
Dependent Claim
71 words
In a disc according to claim 1 or 2, the improvement wherein said prerecorded identification data for each sector further comprises: a fully DC erased gap for providing initial time synchronization; and a predetermined pattern of data bits recorded following each DC erased gap for providing clock synchronization, said predetermined pattern being recorded for each sector and for each track, said track identification code following said predetermined pattern of data bits.
References Cited (Backward Citations)
US3292168A
Cited
US3792454A
Cited
US3864741A
Cited
US4027338A
Cited
US4068267A
Cited
US4087843A
Cited
US4101942A
Cited
US4149200A
Cited
US4238809A
Cited
US4297734A
Cited
US4297737A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-01-02 | 1987-07-04 | 1988-01-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-01-02 | 1991-07-04 | 1992-01-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-01-02 | 1995-07-04 | 1996-01-03 | $7700.00 | Window Closed / Lapsed |