A Study on Pre-Embossed Rigid Magnetic Disk

Toru TAKEDA  Kenjiro WATANABE  

Publication
IEICE TRANSACTIONS on Electronics   Vol.E77-C   No.9   pp.1507-1513
Publication Date: 1994/09/25
Online ISSN: 
DOI: 
Print ISSN: 0916-8516
Type of Manuscript: PAPER
Category: Recording and Memory Technologies
Keyword: 
PERM disk,  hard disk,  magnetic recording,  embossed position marks,  eccentricity,  time domain measurement,  

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Summary: 
A new positioning method for higher track density hard disk using embossed-servo-mark magnetic disks is proposed. An embossed-servo-mark medium with grooved-guard-band data tracks for 208 TPMM was developed using molded plastic substrate. The marks were magnetized so that conventional magnetic head can reproduce position signals. Simple analogy from optical disk track following to magnetic disk track following was taken and examined. A DSP controlled feed-forward servo was introduced to resolve the inherent eccentricity caused by mounting preformed tracks onto an independent spindle axis. The prototype drives with a form factor of 2.5 inches were designed introducing the disks, the servo scheme and the newly developed orthogonal MR head. As a result, an areal density of 650 kbits/mm2 (about 420 Mbits/in2) recording was successfully demonstrated on the media using 2.5-inch form factor prototype drives.