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US 10,102,875 B1Granted
Servo pattern for precise tracking in optical tapes
AssigneeOracle International Corporation
InventorClark Janssen
Life of this patent
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Abstract
Techniques for performing precise tracking in optical tapes are provided. The techniques include providing and using a servo pattern on an optical tape. The servo pattern includes a first set of parallel physical grooves slanted in a first direction across a width of the optical tape and a second set of parallel physical grooves slanted in a second direction that is different from the first direction across the width of the optical tape. Subsets of the first set of parallel physical grooves alternate with subsets of the second set of parallel physical grooves along a length of the optical tape. Two subsets of the first set of parallel physical grooves separated by one subset of the second set of parallel physical grooves form a servo frame in the optical tape.
Claims18
An optical tape, comprising:
- a substrate layer comprising:
- a first set of parallel physical grooves slanted in a first direction across a width of the optical tape;
- and
- a second set of parallel physical grooves slanted in a second direction that is different from the first direction across the width of the optical tape;
- a rewritable recording layer;
- and
- a reflective layer that is masked off in portions that overlap with the first and second sets of parallel physical grooves.
4 more elements
An optical tape, comprising:
- a substrate layer comprising:
- a first set of parallel physical grooves slanted in a first direction across a width of the optical tape;
- and
- a second set of parallel physical grooves slanted in a second direction that is different from the first direction across the width of the optical tape,
- wherein each subset of the first and second sets of parallel physical grooves comprises a number of equally spaced parallel physical grooves, and
- wherein the equally spaced parallel physical grooves are separated by a spacing that is equal to a width of each of the equally spaced parallel physical grooves;
- and
- a rewritable recording layer.
5 more elements
A tape drive, comprising:
- an optical pick-up unit (OPU) comprising:
- a laser configured to read or write to an optical tape, wherein the optical tape comprises:
- a first set of parallel physical grooves slanted in a first direction across a width of the optical tape;
- and
- a second set of parallel physical grooves slanted in a second direction that is different from the first direction across the width of the optical tape;
- and
- an actuator for the laser;
- and
- a controller for the OPU, wherein the controller is configured to:
- periodically detect, for a lateral position of the OPU on the optical tape, a distance between a first subset of parallel physical grooves in the first set of parallel physical grooves and a second subset of parallel physical grooves in the second set of parallel physical grooves by:
- determining a first time interval spanned between detecting the first and second subsets of parallel physical grooves at the lateral position;
- determining a second time interval spanned between detecting the first subset and detecting a third subset of parallel physical grooves in the first set of parallel physical grooves at the lateral position;
- and
- using a proportion comprising the first and second time intervals to identify the data track at the lateral position;
- identify a data track at the lateral position based on the distance;
- and
- use the distance to maintain the lateral position of the OPU during reading and writing of the data track by the laser.
14 more elements
A tape drive, comprising:
- an optical pick-up unit (OPU) comprising:
- a laser configured to read or write to an optical tape, wherein the optical tape comprises:
- a first set of parallel physical grooves slanted in a first direction across a width of the optical tape;
- and
- a second set of parallel physical grooves slanted in a second direction that is different from the first direction across the width of the optical tape,
- wherein each subset of the first and second sets of parallel physical grooves comprises a number of equally spaced parallel physical grooves, and
- wherein the equally spaced parallel physical grooves are separated by a spacing that is equal to a width of each of the equally spaced parallel physical grooves;
- and
- an actuator for the laser;
- and
- a controller for the OPU, wherein the controller is configured to:
- periodically detect, for a lateral position of the OPU on the optical tape, a distance between a first subset of parallel physical grooves in the first set of parallel physical grooves and a second subset of parallel physical grooves in the second set of parallel physical grooves;
- identify a data track at the lateral position based on the distance;
- and
- use the distance to maintain the lateral position of the OPU during reading and writing of the data track by the laser.
12 more elements
A method, comprising:
- receiving a series of readings generated by an optical pick-up unit (OPU) in a tape drive, wherein the series of readings is generated from:
- a first set of parallel physical grooves slanted in a first direction across a width of the optical tape;
- and
- a second set of parallel physical grooves slanted in a second direction that is different from the first direction across the width of the optical tape;
- using the readings to periodically detect, for a lateral position on the optical tape, a distance between a first subset of parallel physical grooves in the first set of parallel physical grooves and a second subset of parallel physical grooves in the second set of parallel physical grooves by:
- determining a first time interval spanned between detecting the first and second subsets of parallel physical grooves at the lateral position;
- determining a second time interval spanned between detecting the first subset and detecting a third subset of parallel physical grooves in the first set of parallel physical grooves at the lateral position;
- and
- using a proportion comprising the first and second time intervals to identify the data track at the lateral position;
- identifying a data track at the lateral position based on the distance;
- and
- using the distance to maintain the lateral position during reading and writing of the data track by the OPU.
9 more elements
Dependencies are inferred from the claim text.