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EP0066085A1
Expired / Lapsed
EP
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Disk file and method of transducing
Assignee: International Business Machines Corp
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Filing: 1982-04-27
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Granted: —
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Expires: 2002-04-27
Abstract
Abstract A magnetic disk file for storing data on a rotating magnetic disk (10) having concentric recording tracks includes where a first inner group (16) of tracks (14) is recorded at one frequency f1, providing optimum track capacity for these tracks, and a second outer group (17) of tracks (15) are recorded at a second higher frequency f2, which also provides optimum track capacity for these tracks. At each address position, each of two magnetic transaucers (11, 12) is associated with a track from different groups. During the writing or reading of serial-by-byte data, the two tracks are transduced on successive revolutions. Suitable switching circuitry for switching from one transducer to the other in track is provided and also for changing the clock frequency. The system further inclues suitable disk formatting circuitry for converting the two physical tracks into one (or more) logical tracks having equal byte capacity. <??>The method of transducing includes the steps of switching an index from one transducer to the other and adjusting the clock frequency accordingly, so that all logical records have the same capacity. The magnetic disk may be divided into more than two groups of tracks, if desired.
Inventors
- 👤 John Matthew Grogan
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-28 21:06
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/012; G11B20/00; G11B20/10; G11B20/12; G11B20/1217; G11B20/1258
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
167 words
1 A magnetic disk file including at least one rotatable disk (10) having a plurality N of groups (16,17) of concentric physical recording tracks (14,15), a plurality N of magnetic transducers (11,12), each of which is associated with a different group of tracks and which are positionable conjointly to selected tracks in different groups in response to an externally supplied address signal, means (36,37) for generating a plurality N of different recording frequencies which control the linear recording densities in tracks of the respective groups whereby the byte capacity per track of the groups of tracks differ, at least one logical track (LT01) including a first portion on a physical track (PT1) of one group and a second portion on a corresponding physical track (PT2) of another group, and means for switching from one recording frequency to another in response to sensing an index signal transduced from the file at the end of transducing the first portion, whereby the portions may be transduced in a continuous operation.
Claim 2
Dependent Claim
167 words
1 A magnetic disk file including at least one rotatable disk (10) having a plurality N of groups (16,17) of concentric physical recording tracks (14,15), a plurality N of magnetic transducers (11,12), each of which is associated with a different group of tracks and which are positionable conjointly to selected tracks in different groups in response to an externally supplied address signal, means (36,37) for generating a plurality N of different recording frequencies which control the linear recording densities in tracks of the respective groups whereby the byte capacity per track of the groups of tracks differ, at least one logical track (LT01) including a first portion on a physical track (PT1) of one group and a second portion on a corresponding physical track (PT2) of another group, and means for switching from one recording frequency to another in response to sensing an index signal transduced from the file at the end of transducing the first portion, whereby the portions may be transduced in a continuous operation.
Claim 3
Dependent Claim
39 words
2 A file according to claim 1, including means for generating an index signal which defines the beginning of each physical track and means for selectively switching between transducers in response to sensing the index signal from the file.
Claim 4
Dependent Claim
24 words
3 A file according to claim 1 or 2, including means for phase synchronizing the selected recording frequency to the rotation of the file.
Claim 5
Dependent Claim
42 words
4 A file according to claim 1, 2 or 3, in which the means for generating recording frequencies includes variable frequency oscillator means and means for switching the oscillator means from one frequency to another in response to sensing the index signal.
Claim 6
Dependent Claim
31 words
5 A disk file according to claim 1, 2, 3 or 4, in which the corresponding physical tracks of the groups are formatted into a plurality of equal capacity logical tracks.
Claim 7
Dependent Claim
31 words
6 A file according to claim 5, in which each logical track has a capacity which is a submultiple of the sum of the byte capacities of the N physical tracks.
Claim 8
Dependent Claim
105 words
7 A method of transducing concentric physical tracks in a plurality N of groups on a rotating magnetic disk, which groups of tracks are recorded at different frequencies that result in each track of the different groups having a different byte capacity, the method comprising conjointly positioning a plurality N of transducers to selected physical tracks in different groups in response to a single address signal, and transducing each physical track in turn with a transducer at a corresponding frequency, including sensing the end of each physical track and, in response to such sensing, switching from one transducer and frequency to another transducer and frequency.
Claim 9
Dependent Claim
105 words
7 A method of transducing concentric physical tracks in a plurality N of groups on a rotating magnetic disk, which groups of tracks are recorded at different frequencies that result in each track of the different groups having a different byte capacity, the method comprising conjointly positioning a plurality N of transducers to selected physical tracks in different groups in response to a single address signal, and transducing each physical track in turn with a transducer at a corresponding frequency, including sensing the end of each physical track and, in response to such sensing, switching from one transducer and frequency to another transducer and frequency.
Claim 10
Dependent Claim
42 words
8 A method according to claim 7, including generating a signal indicating the end of a logical track each time a predetermined number of byte positions has been transduced by the transducers to provide one or more logical tracks of equal capacity.
Claim 11
Dependent Claim
35 words
9 A method according to claim 7 or 8, including the step of generating an index signal at the end physical track and supplying the index signal to control circuitry to initiate the switching step.
Claim 12
Dependent Claim
58 words
10 A method according to claim 7, 8 or 9, in which a first logical record is transduced at a first data rate, a second logical record has a first portion transduced at the first data rate, and another portion transduced at a second data rate, and a third logical record is transduced at the second data rate.
References Cited (Backward Citations)
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