Optical servo system for a tape drive

• US 6,480,351 B2
• Filed: 02/05/2001
• Issued: 11/12/2002
• Est. Priority Date: 12/01/1997
• Status: Expired due to Term

• Current Assignee: Storage Technologies Corporation (Oracle Corporation)
• Original Assignee: Storage Technologies Corporation (Oracle Corporation)
• Inventors: Leonhardt, Michael Lawrence, Wilson, Scott David
• Primary Examiner(s): Sniezek, Andrew L.
• Assistant Examiner(s): SLAVITT, MITCHELL R
• Application Number:
  US09/775,893
• Publication Number:
  US 20010006437A1
• Time in Patent Office: 645 Days
• Field of Search: 360/77.12, 360/75, 360/77.03, 360/78.02, 360/78.11, 369/44.11, 369/44.14, 369/44.17, 369/97
• US Class Current: 360/77.12
• CPC Class Codes: G11B 15/08 by photoelectric sensing G11B15/07 takes precedence
• CPC Class Codes: G11B 15/602 for track selection, acquisition or following
• CPC Class Codes: G11B 20/00086 Circuits for prevention of unauthorised reproduction or copying, e.g. piracy indicating unauthorised use of record carriers in general G11B23/28; scrambling for television signal recording H04N5/913; network architectures or network protocols for network security H04L63/00; cryptographic mechanisms or cryptographic arrangements for secret or secure communication H04L9/00
• CPC Class Codes: G11B 20/0021 involving encryption or decryption of contents recorded on or reproduced from a record carrier
• CPC Class Codes: G11B 21/085 with track following of accessed part
• CPC Class Codes: G11B 21/103 on tapes
• CPC Class Codes: G11B 2220/90 Tape-like record carriers
• CPC Class Codes: G11B 27/107 of operating tapes
• CPC Class Codes: G11B 27/26 by photoelectric detection, e.g. of sprocket holes
• CPC Class Codes: G11B 27/36 Monitoring, i.e. supervising the progress of recording or reproducing for digital recording G11B20/00 and s.gr.; for monitoring, testing or measuring of TV recorders of the type covered by H04N5/76 and subgroups, see H04N17/06
• CPC Class Codes: G11B 5/5508 Control circuits therefor G11B5/5513 takes precedence
• CPC Class Codes: G11B 5/584 for track following on tapes
• CPC Class Codes: G11B 5/588 by controlling the position of the rotating heads by controlling the speed of the record carrier G11B15/467; by controlling speed of the heads G11B15/473; by moving the transducing part of the head relative to the headwheel, in the direction of the scanning movement G11B15/1841

Abstract

The optical servo system for a tape drive that functions to align a read/write head with the data tracks written on a recording surface of a tape by reading optical servo tracks that are formed on the back side of the tape. This process decouples the magnetic recording of data on the recording surface of the tape from the optical servo system which makes use of servo tracks formed on the back side of the tape. The data storage capacity of the tape is increased since the entire recording surface of the tape is filled with data tracks and the precise alignment of the read/write head makes it possible to place the data tracks closer together. Regions of contrasting reflectivity or phase are also provided on a surface of the read/write head to enable the optical servo system to view an image of both the read/write head and the entire back side of the tape to thereby align the movable read/write head with the data tracks.

Claims

1. A method of aligning a head with a storage media, comprising the steps of:

reading at least one optical feature reflected from the storage media;

reading at least one optical feature reflected from the head; and

aligning the head to the storage media based upon the at least one optical feature reflected from the storage media and the at least one optical feature relected from the head.

2. A system for aligning a head with at least one of a plurality of data tracks written on a first side of a data storage media as said media passes over said head, wherein said media also includes optical servo features formed on a second side of said media, said system comprising:

an optical circuit that detects at least a portion of said optical servo features reflected from said second side of said media;

an electrical circuit, operatively coupled to said optical circuit, that aligns said head with said at least one of a plurality of data tracks in response to said detected optical servo fields; and

a media drive, wherein the head is moveable attached to the media drive, and wherein the optical circuit comprises an optical sensor that is fixedly attached to the media drive.

3. In a tape drive, a system for aligning a read/write head, that is moveably attached to said tape drive, with a selected set of a plurality of data tracks written on a first side of a tape as said tape passes over said read/write head, wherein said tape also includes optical servo features formed on a second side of said tape, said system comprising:

an optical sensor fixedly attached to said tape drive that detects at least a portion of said optical servo features reflected from said second side of said tape; and

an electrical circuit, operatively coupled to said optical circuit, that aligns said read/write head with said selected set of a plurality of data tracks on said first side of said tape in response to said detected optical servo features.

4. A tape library comprising a plurality of tape drives, at least a portion of said tape drives comprising:

means for reading at least one optical feature reflected from the storage media;

means for reading at least one optical feature reflected from the head; and

means for aligning the head to the storage media based upon the at least one optical feature reflected from the storage media and the at least one optical feature reflected from the head.

5. In a tape library comprising a plurality of tape drives, at least a portion of said tape drives operable for aligning a head with a storage media and comprising the steps of:

reading at least one optical feature reflected from the storage media;

reading at least one optical feature reflected from the head; and

aligning the head to the storage media based upon the at least one optical feature reflected from the storage media and the at least one optical feature reflected from the head.