US 4,056,830 AGranted

Utilizing data for transducer positioning

AssigneeBurroughs Corporation

InventorDouglas A. Smith

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Abstract

The recorded data is also used for positioning purpose, accordingly the data on adjacent tracks is recorded at different clock frequencies so that the data on one track can be discriminated from the data on the other track.

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Claims9

Dependent claims

A method of recording data at different clock frequencies on a plural-track record disk comprising the steps of:

detecting addresses of a plurality of tracks;
generating a nominal clock frequency;
varying said nominal clock frequency by a predetermined amount, said amount dependent on said detected addresses;
generating a plurality of differing clock frequencies from said varying nominal clock frequency, said plurality of clock frequencies corresponding to said plurality of detected track addresses;
sorting said differing clock frequencies into a plurality of frequency groups;
dividing each of said frequency groups into two subgroups wherein said differing clock frequencies increase with respect to said nominal clock frequency in one of said subgroups and decrease with respect to said nominal clock frequency in said other subgroup;
and
recording said data at said plurality of clock frequencies on said plural-track record disk, each of said differing clock frequencies being interlaced between adjacent tracks such that each odd track has a relatively large clock frequency difference with respect to an adjacent even track but a relatively small clock frequency difference with respect to a next closest odd track, said clock frequency at which said data is recorded being the same at corresponding tracks among said plurality of groups.

5 more elements

Dependencies are inferred from the claim text.

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Abstract

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Claims9

Dependent claims

A method of recording data at different clock frequencies on a plural-track record disk comprising the steps of:

detecting addresses of a plurality of tracks;
generating a nominal clock frequency;
varying said nominal clock frequency by a predetermined amount, said amount dependent on said detected addresses;
generating a plurality of differing clock frequencies from said varying nominal clock frequency, said plurality of clock frequencies corresponding to said plurality of detected track addresses;
sorting said differing clock frequencies into a plurality of frequency groups;
dividing each of said frequency groups into two subgroups wherein said differing clock frequencies increase with respect to said nominal clock frequency in one of said subgroups and decrease with respect to said nominal clock frequency in said other subgroup;
and
recording said data at said plurality of clock frequencies on said plural-track record disk, each of said differing clock frequencies being interlaced between adjacent tracks such that each odd track has a relatively large clock frequency difference with respect to an adjacent even track but a relatively small clock frequency difference with respect to a next closest odd track, said clock frequency at which said data is recorded being the same at corresponding tracks among said plurality of groups.

5 more elements

Dependencies are inferred from the claim text.

Description5,403 words

Summary1,201 words

#The present invention relates to a novel transducer head assembly for use with a multi-track record disk. The invention also relates to a method and apparatus using the novel transducer head assembly for recording, reproducing or erasing data with respect to the record disk, and further, to a method of using such assembly for initializing a virgin record disk.

#Record disks are commonly used for storing data in computers and other data processing systems. Such record disks are provided on both faces with a layer of a magnetizable material for recording the data in the form of a plurality of spaced, annular tracks. Some disk systems, or disk files as they are frequently called, include a plurality of such record disks stacked on a common spindle and driven by a common drive, whereas others include only one record disk. Because of the expense involved in providing a head for each track, most systems use one head per disk, which means that the head must be very accurately positioned to align itself with the selected track with respect to which the data is to be recorded, reproduced, or erased.

#In order to obtain the maximum storage capacity per disk, a large number of tracks are provided on each surface, for example 200 tracks per inch or more. A factor limiting the track density, however, is the precision with which a head can be positioned with respect to a selected track. Positional inaccuracies may arise from a number of factors, including spindle eccentricity; temperature-coefficient variations with respect to this disk, base, head and transducer; nonlinearity in the transducer; and setting-up errors. If the head is not precisely positioned on a track from which recorded data is to be read, the signal level will be reduced and errors may therefore occur.

Brief description of the drawings5 figures

#The invention is herein described, by way of example only, with respect to a preferred embodiment thereof illustrated in the accompanying drawings, wherein:

#FIG. 1 is a schematic illustration of a magnetic transducer head assembly constructed in accordance with the invention, and a single-disk recording system using such head assembly;

#FIG. 2, consisting of 2A and 2B, schematically illustrates the positioning, with respect to the track on one face of the record disk, of one of the heads in the transducer head assembly of FIG. 1;

Detailed description4,037 words

#The recording system illustrated in FIG. 1 includes a single magnetic disk 2 mounted on a spindle 4 rotated by a disk drive 6. Both faces 2a, 2b of the record disk are provided, by an initializing procedure such as one described below, with a plurality of spaced annular tracks with respect to which data is to be recorded, reproduced or erased by means of a transducer head assembly, generally designated 8. This head assembly includes a support 10 carrying an upper magnetic transducer head 12 cooperable with the upper face 2a of the record disk, and a lower transducer head 14 cooperable with the lower face 2b of the magnetic disk.

#The transducer head assembly 8 is positioned with respect to record disk 2 by means of a drive, generally designated 16. The latter drive moves the head assembly radially with respect to spindle 4, to a selected track as specified by an address supplied from an input device. The input device, which for the sake of simplification is represented by central processor block 18, supplies the data to be recorded and receives the data to be reproduced, and also supplies the track address at which the operation is to be performed.

#Drive 16 is controlled by a system, generally designated 20, to precisely align the head during the recording, reproducing, or erasing operation with respect to the selected track. The data path from or to central processor 18 also includes system 20, as schematically shown in FIG. 1.

Abstract

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Claims9

Abstract

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Claims9

Description5,403 words

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Classification4 codes

Life of this patent

Description5,403 words