Disc cartridge sector formatting arrangement and record addressing system
First Claim
1. In a computer controlled magnetic disc formatting arrangement of the type wherein sector mark code signals and format data signals are supplied to a write head for recording on a disc to be formatted, the improvement comprising:
- a first oscillator for supplying a recording clock for said format data signals at a first frequency;
a second oscillator for supplying a recording clock for said sector mark code signals at a second frequency;
switching means for connecting said first oscillator output to said write head during recording to said sector mark code signals and for connecting said second oscillator output to said write head recording of said format data signals;
sensing means for reading the signals recorded on said disc by said write head;
sector detection circuit means having an input responsive to said sensing means for producing a sector pulse to an output upon detection of said sector detection circuit means comprising an optimal filter having an input responsive to said sensing means for removing noise and other extraneous signal distortion from said sector mark signal and supplying a filtered sector pulse at an output, and an adaptive threshold detector having an input responsive to the output of said optimal filter for providing a final sector pulse output only when the width of said filtered sector pulse exceeds a selected percentage of the maximum sector pulse width within the track containing said filtered sector pulse; and
,data detection means having an input responsive to said sensing means for providing a data checking signal at an output for certification thereof.
2 Assignments
0 Petitions
Accused Products
Abstract
A sector formatting and record addressing scheme and associated electronic recording and detection control systems for a removable cartridge disc used in a magnetic information storage unit. Indelible sector mark and record address/format information are electronically pre-recorded on the disc at the factory using a high precision cartridge writer. This cartridge writer phase-locks the recording clock to a magnetically recorded clocking disc rotating on the same shaft as the disc via an associated position transducer to write an exact number of bytes on each track having a precise physical relationship to each other. Separate recording clocks having a wide bit-frequency spectral separation are used to write sector mark and address/format data to provide maximum sector detection reliability. The cartridge writer control system computes the optimum length of sector code for the customer-specified record size. The sector format arrangement is designed to facilitate address checking and data recovery in the user environment with a minimum of control complexity.
14 Citations
14 Claims
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1. In a computer controlled magnetic disc formatting arrangement of the type wherein sector mark code signals and format data signals are supplied to a write head for recording on a disc to be formatted, the improvement comprising:
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a first oscillator for supplying a recording clock for said format data signals at a first frequency; a second oscillator for supplying a recording clock for said sector mark code signals at a second frequency; switching means for connecting said first oscillator output to said write head during recording to said sector mark code signals and for connecting said second oscillator output to said write head recording of said format data signals; sensing means for reading the signals recorded on said disc by said write head; sector detection circuit means having an input responsive to said sensing means for producing a sector pulse to an output upon detection of said sector detection circuit means comprising an optimal filter having an input responsive to said sensing means for removing noise and other extraneous signal distortion from said sector mark signal and supplying a filtered sector pulse at an output, and an adaptive threshold detector having an input responsive to the output of said optimal filter for providing a final sector pulse output only when the width of said filtered sector pulse exceeds a selected percentage of the maximum sector pulse width within the track containing said filtered sector pulse; and
,data detection means having an input responsive to said sensing means for providing a data checking signal at an output for certification thereof. - View Dependent Claims (2, 3, 4, 5)
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6. The method of formatting a sector within a track of a magnetic information storage disc comprising the steps of:
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recording at a first clock frequency in a first field of said sector a sector mark code having a length proportional to the length of the data record to be contained within said sector; recording at a second clock freqency in a second field of said sector an encoded word representing the logical address of said data record within said sector; and
,recording at said second clock frequency in a third field of said sector an encoded word representing the logical address of the data record contained within the next successive sector of said track. - View Dependent Claims (7, 8)
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9. The method of using a magnetic recording head to format a disc sector comprising the steps of:
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supplying a sector mark code having a length proportional to the length of the data record to be recorded within said sector; supplying a sequence of format information, said sequence including a first encoded word representing the logical address of the data record within said sector, and a second encoded word representing the logical address of the data record within the next successive sector; generating a first clocking signal; generating a second clocking signal at a different frequency from said first clocking signal; and
,gating said sector mark code to said recording head at said first clocking frequency, and gating said format information to said recording head at said second clocking frequency to record said sector mark code in a first field of said sector, said first encoded word in second field of said sector and said second encoded word in a third field of said sector.
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10. The method of locating a computer addressed data record within a track of a magnetic information storage disc comprising the steps of:
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detecting in a first field of each sector within said track a first encoded word representing the logical address of the record contained in the next successive sector within said track; making a first comparison between each of said first encoded words within said first fields and the logical address of the record requested by said computer; detecting in a second field of the next successive sector within said track a second encoded word representing the logical address of the data record within said next successive sector; making a second comparison between said second encoded word in said second field of said next successive sector and the logical address of the record requested by said computer; and
,reading out the record in said next successive sector after performing said first and second comparisons. - View Dependent Claims (11, 12)
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13. In a magnetic information storage disc having a plurality of tracks thereon, each track containing a plurality of sectors, each of said sectors including a data record portion and an identification portion containing the logical address of the data record within said sector, the improvement wherein said identification portion of each said sector includes the logical address of the data record within the next logically successive sector in the same track of said disc.
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14. In a magnetic information storage disc having a plurality of tracks, each track having a plurality of sectors each sector containing a sector mark code identifying the beginning of said sector, the improvement wherein said sector mark code has a length which is proportional to the length of the data record within said sector.
Specification