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Publication numberCA2148390 A1
Publication typeApplication
Application numberCA 2148390
Publication date31 Dec 1995
Filing date2 May 1995
Priority date30 Jun 1994
Also published asCA2148390C, CN1124399A, CN1168090C, CN1320524C, CN1320526C, CN1661682A, CN1661683A, CN1783219A, CN1783224A, CN100350458C, CN100363985C, DE69507210D1, DE69507210T2, EP0690442A2, EP0690442A3, EP0690442B1, US5689384, US6021013, US6282051, US6320719, US6462904
Publication numberCA 2148390, CA 2148390 A1, CA 2148390A1, CA-A1-2148390, CA2148390 A1, CA2148390A1
InventorsThomas Robert Albrecht, Robert Carl Barrett, James Howard Eaton
ApplicantThomas Robert Albrecht, Robert Carl Barrett, James Howard Eaton, International Business Machines Corporation
Export CitationBiBTeX, EndNote, RefMan
External Links: CIPO, Espacenet
Timing based servo system for magnetic tape systems
CA 2148390 A1
Abstract
A track following servo system is disclosed for use with magnetic tape systems in which magnetic servo track patterns contain transitions recorded at more than on azimuthal orientation across the width of the servo track. The timing of a signal derived from reading at any point across the width of such a pattern varies continuously as the read head is moved across the servo track. The pattern is read by a servo read head whose width is small compared to the servo track pattern.
The combination of a wide servo pattern and a narrow servo read head offers excellent position sensing linearity and dynamic range. In the preferred embodiment, the servo read head is also narrow with respect to the data tracks, which provides the additional advantages of superior immunity to position sensing errors caused by defects or temporal variations in the servo read head, defects in the servo pattern on the tape, wear of the head or tape, or debris collection on the head or tape.
Position sensing with this system is achieved by deriving a ratio of two servo pattern intervals and therefore is insensitive to tape speed during reading. The servo patterns may include spacing intervals recognizable for error detection and correction purposes. Servo tracks are recorded using a patterned multiple gap servo write head whose magnetic gaps have geometries appropriate to generate the desired servo patterns. The patterned gaps of the servo write head are produced by photolithographically defined electroplating of permalloy on a ferrite ring head structure.
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Classifications
International ClassificationG11B5/584, G11B5/58, G11B5/265, G11B5/596, A63F7/02, G11B21/10
Cooperative ClassificationG11B5/584
European ClassificationG11B5/584
Legal Events
DateCodeEventDescription
22 Nov 1999EEERExamination request
6 Jul 2015MKEXExpiry
Effective date: 20150504