Patent US3614756A successfully refreshed from Google Patents.
US3614756A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Magnetic record with servo track perpendicular to information track
Assignee: International Business Machines Corp
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Filing: 1970-01-21
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Granted: 1971-10-19
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Expires: 1990-01-21
Abstract
Abstract The invention relates to a servosystem used in a random access disk memory system which comprises a magnetic disk having servo tracks recorded such that the magnetic domains within the servo tracks are aligned radially from the center of the disk and data tracks which have the magnetic domains are aligned concentrically about the center of the disk, and a transducer capable of developing a data signal as a function of the rate of change of the magnetic flux associated with the data tracks and a servo signal generated by the magnitude of the absolute flux magnitude that it presented to the transducer by the transducer''s relationship to the servo tracks on the magnetic disk, the servo signal and the data signals being generated either simultaneously or alternately in the magnetic transducer.
Inventors
- 👤 Robert P Mcintosh
- 👤 Marco Padalino
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 10:40
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/48; G11B5/488; G11B5/4886; G05; G05D; G05D3/00; G05D3/12; G05D3/20; G11B5/58; G11B5/596; G11B5/59633; G11B5/5965
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
87 words
A transducer-positioning servosystem for use in a random access magnetic disk memory comprising: a magnetic disk having servo tracks and data tracks recorded thereon, the magnetic domains of said servo tracks being orientated radially from the center of said magnetic disks, and the magnetic domains of said data tracks being orientated concentrically about the center of said magnetic disks; and a magnetic transducer means for sensing said data tracts by a rate of change sensing means and for sensing said servo tracks by an absolute flux-sensing means.
Claim 2
Dependent Claim
87 words
A transducer-positioning servosystem for use in a random access magnetic disk memory comprising: a magnetic disk having servo tracks and data tracks recorded thereon, the magnetic domains of said servo tracks being orientated radially from the center of said magnetic disks, and the magnetic domains of said data tracks being orientated concentrically about the center of said magnetic disks; and a magnetic transducer means for sensing said data tracts by a rate of change sensing means and for sensing said servo tracks by an absolute flux-sensing means.
Claim 3
Dependent Claim
83 words
A transducer-positioning servosystem as set forth in claim 1 wherein said magnetic transducer means is comprised of an integral structure comprising: a magnetic-sensing portion having a nonmagnetic gap for sensing the rate of change of magnetic flux of a data signal recorded in said data tracks when said data tracks are moved relative to said nonmagnetic gap; and a flux-sensing portion having a flux-sensing gap disposed at an angle to said nonmagnetic gap for sensing the absolute flux value from said servo tracks.
Claim 4
Dependent Claim
41 words
A transducer positioning servosystem as set fourth in claim 2 wherein said flux-sensing gap in said flux-sensing portion of said magnetic transducer is disposed at an angle of 90*from said nonmagnetic gap in said magnetic sensing portion of said magnetic transducer.
Claim 5
Dependent Claim
125 words
A transducer-positioning servosystem as set forth in claim 1 wherein said magnetic disk is a magnetic dual layer, dual coercivity disk comprising: a plurality of adjacent concentric serve tracks recorded in the high-coercivity layer as a series of discrete magnetized domains orientated radially from the center of said disk, each of said servo tracks having all domains in the same orientation, and alternate ones of said servo tracks having domains of opposite orientation; and a plurality of concentric data tracks recorded in the low-coercivity layer as is a series of discrete magnetized domains orientated concentrically around the center of said disk, said servo tracks being at least the width of said data tracks, and each of said servo tracks overlapping evenly on said data tracks.
Claim 6
Dependent Claim
100 words
A transducer-positioning servosystem as set forth in claim 4 wherein said magnetic transducer means has an integral structure comprising: a magnetic-sensing portion having a nonmagnetic gap for sensing rate of change of magnetic flux of a data signal recorded in one of said data tracks when said data track is moved relative to said nonmagnetic gap; a flux-sensing portion having a flux-sensing gap disposed at an angle to said nonmagnetic gap for continuously sensing the absolute flux value from said servo tracks; and said magnetic transducer simultaneously sensing both data from said tracks and servo information from said servo tracks.
Claim 7
Dependent Claim
39 words
A transducer-positioning servosystem as set forth in claim 5 wherein Said flux-sensing gap in said flux-sensing portion of said magnetic transducer is disposed at an angle of 90*from said nonmagnetic gap in said magnetic-sensing portion of said magnetic transducer.
Claim 8
Dependent Claim
128 words
A transducer-positioning servosystem as set forth in claim 1 wherein said magnetic disk has alternating first and second sections comprising: a plurality of adjacent concentric servo tracks recorded in said first sections as a series of discrete magnetized domains orientated radially from the center of said disk, each of said servo tracks having all domains in the same orientation and alternate ones of said servo tracks having domains of opposite orientations; and a plurality of concentric data tracks recorded in said second sections as a series of discrete magnetized domains orientated concentrically about the center of said disk, said servo tracks being at least the width of said data tracks, and the center of each of said data tracks being the boundary between two adjacent said servo tracks.
Claim 9
Dependent Claim
124 words
A transducer-positioning servosystem as set forth in claim 7 wherein said magnetic transducer means has an integral structure comprising: a magnetic sensing portion having a nonmagnetic gap for sensing rate of change magnetic flux of a data signal recorded on one of said data tracks when said data track is moved relative to said nonmagnetic gap; a flux-sensing portion having a flux-sensing gap disposed at an angle to said nonmagnetic gap for sensing the absolute flux value from said servo tracks; and said magnetic transducer means providing a data signal from said magnetic sensing portion from data recorded in said second sections of said magnetic disks and for producing a servo signal from the servo tracks in said first sections of said magnetic disk.
Claim 10
Dependent Claim
41 words
A transducer-positioning servosystem as set forth in claim 8 wherein said flux-sensing gap in said flux-sensing portion of said magnetic transducer is disposed at an angle of 90* from said nonmagnetic gap in said magnetic sensing portion of said magnetic transducer.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-10-18 | 1975-04-19 | 1975-10-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-10-18 | 1979-04-19 | 1979-10-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-10-18 | 1983-04-19 | 1983-10-19 | $7700.00 | Window Closed / Lapsed |