Method for generating a reference signal from unique servo mark pattern detection
AssigneeFujitsu Limited
InventorsMary E. Dunn, David E. Norton, Jr.
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Abstract
A plurality of data sequences having patterns distinguishable from informational data are recorded as a servo mark portion of servo information on a disk. Upon decoding a predetermined number of these data sequences, a determination is made as to whether an accurately located servo mark has been detected. The detected servo mark provides a reference from which the beginning of recorded servo burst data can be located, thereby enabling all of the servo burst data to be read. The presence of defects does not inhibit the detection of the servo mark.
Claims27
A method of generating a signal mark pattern for a disk storage system for distinguishing servo data from informational data, said method comprising the steps of:
- generating a first plurality of mark data sequences each having a first length, generating a second plurality of mark data sequences each having a second length, in which at least one mark data sequence contained in the first and second pluralities of mark data sequences has a data run-length greater than a predetermined data run-length, generating a reference signal located after said second plurality of mark data sequences, and recording said signal mark pattern including said reference signal in an area located prior to said servo data.
A method of generating a reference mark from a signal pattern having a first plurality of data sequences each having a first length, a second plurality of data sequences each having a second length, in which at least one data sequence contained in the first and second pluralities of data sequences have a data run-length greater than a predetermined data run-length, and a reference signal located after said second plurality of data sequences, said method comprising the steps of:
- detecting the lengths of a predetermined number of said data sequences contained within said first and second pluralities of data sequences, determining whether the detected lengths satisfy predetermined criteria indicative of whether an accurately located reference mark can be generated, and generating said reference mark so as to coincide with said reference signal only if said criteria are satisfied.
A method of generating a reference mark from a signal pattern having a first plurality of data sequences each having a first length, a second plurality of data sequences each having a second length, in which at least one data sequence contained in the first and second pluralities of data sequences has a data run-length greater than a predetermined data run-length, and a reference signal located after said second plurality of data sequences, said method comprising the steps of:
- detecting the lengths of a predetermined number of said data sequences contained within said first and second pluralities of data sequences, determining whether the detected lengths satisfy predetermined criteria indicative of whether an accurately located reference mark can be generated, said criteria including detecting three data sequences, two of which having respectively prefixed lengths and the third having a length equal to or greater than a pre-established amount, from the combination of said first and second pluralities of data sequences, and generating said reference mark so as to coincide with said reference signal only if said criteria are satisfied.
A method of generating a reference mark from a signal pattern having a first plurality of data sequences each having a first length, a second plurality of data sequences each having a second length, in which at least one data sequence contained in the first and second pluralities of data sequences has a data run-length greater than a predetermined data run-length and in which each data sequence contained in the first and second pluralities of data sequences is defined by a transition, and a reference signal located after said second plurality of data sequences having first and second trigger transitions separated from each other by a predetermined length, said method comprising the steps of:
- detecting the lengths of three data sequences contained within the combination of said first and second pluralities of data sequences, determining whether the detected three lengths satisfy predetermined criteria indicative of whether an accurately located reference mark can be generated, and generating said reference mark in response tot he respective one of said first and second trigger transitions which follows by more than a minimum length the detection of the three data sequences that satisfy said criteria only if said criteria are satisfied.
Dependencies are inferred from the claim text.