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EP0339851A2 Expired / Lapsed EP ⏱️ 0.0 years remaining

A magnetic record disk with embedded servo information

Assignee: International Business Machines Corp
•
Filing: 1989-04-18
•
Granted: —
•
Expires: 2009-04-18
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Abstract

Abstract A discrete track magnetic record disk is provided with a plurality of angularly spaced servo sectors (18), each sector being formed of a plurality of discrete blocks (32, 34, 36, 38) of magnetic material which are magnetically polarised in the disk's circumferential direction. These discrete servo blocks (32, 34, 36, 38) and the discrete magnetic tracks (20, 22, 24) are formed at the same time during the fabrication of the record disk so that each servo block is precisely and permanently radially aligned with an associated discrete data track. Following the fabrication of the disk, each of the servo blocks is exposed to the magnetic field generated by passing a direct current (DC) through a recording head. In this manner each of the servo blocks becomes magnetised in the circumferential direction and thereby presents two discrete magnetic transitions to a servo read head or a read/write head.

Inventors

  • 👤 Karl Arnold Belser
  • 👤 Tarek Makansi
  • 👤 Ian Lewis Sanders

Bibliographic Details

Application Number —
Jurisdiction EP
Data Source google_patents
Last Synchronized 2026-10-27 19:54
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/74; G11B5/82; B; B82; B82Y; B82Y10/00; G11B5/48; G11B5/58; G11B5/596; G11B5/59633; G11B5/5965; G11B5/743

Claims Analysis

Total Claims: 7
Claim 1
Independent Claim 74 words
A magnetic record disk comprising: a plurality of concentric substantially circular discrete tracks (20, 22, 24) of magnetic material located on a substrate for the magnetic recording of data; and a plurality of discrete servo blocks (32, 34, 36, 38) of magnetic material located on the substrate in at least one sector of the disk, each of the blocks being aligned radially with an associated data track and magnetically polarised in the circumferential direction.
Claim 2
Dependent Claim 74 words
A magnetic record disk comprising: a plurality of concentric substantially circular discrete tracks (20, 22, 24) of magnetic material located on a substrate for the magnetic recording of data; and a plurality of discrete servo blocks (32, 34, 36, 38) of magnetic material located on the substrate in at least one sector of the disk, each of the blocks being aligned radially with an associated data track and magnetically polarised in the circumferential direction.
Claim 3
Dependent Claim 24 words
A record disk as claimed in claim 1, further comprising synchron­isation and gain stripes of circumferentially magnetically polarised magnetic material located in the sector.
Claim 4
Dependent Claim 40 words
A record disk as claimed in claim 1 or claim 2, wherein the servo blocks are located in a plurality of sectors substantially equally angularly spaced around the disk, whereby the data tracks are divided into a plurality of arcs.
Claim 5
Dependent Claim 20 words
A record disk as claimed in claim 3, wherein the servo blocks in each sector form a radially repetitive pattern.
Claim 6
Dependent Claim 16 words
A record disk as claimed in claim 4, wherein the repetitive pattern is a quadrature pattern.
Claim 7
Dependent Claim 29 words
A record disk as claimed in any preceding claim, in which the tracks and servo blocks are formed from a thin film of a magnetic alloy or metal oxide.

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