Magnetic head tester using magnetic disk with pre-written servo
US7580218B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Sep 1, 2005 |
| Grant date | Aug 25, 2009 |
| Priority date | — |
| Expiry date | Sep 1, 2025 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B5/455
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A method for operating a head testing apparatus (spin stand) using a mounted hard disk that has had its servo track information pre-written in an external servo-writing apparatus rather than in the testing apparatus itself. This insures more accurate servo-track writing and renders the testing operation more efficient. The problem of repeatable runout (RRO) associated with the transfer of a disk written in one machine to another is eliminated by forming a corrected position error signal (PES) by subtracting the average offset of one or more servo sector locations previously calculated using limited bandwidth operation of the servomechanism, from the position error signal generated during full bandwidth servo operation of the apparatus.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.