Iterative repeatable run-out nulling for magnetic head tester
US7672073B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Feb 14, 2008 |
| Grant date | Mar 2, 2010 |
| Priority date | — |
| Expiry date | Apr 23, 2028 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B2220/2516
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A method for operating a head testing apparatus or, more generally, a host hard disk drive using a mounted hard disk that has had its servo track information pre-written in an external servo-writing apparatus rather than in the head testing or host apparatus itself. The method eliminates repeatable errors and repeatable runout by effectively replacing the pre-written servo tracks, which are eccentric, with new track profiles that are tracked like circular tracks. The problem of repeatable errors is caused by repeatable runout superimposed upon written-in position errors when a disk written in one machine is transferred to another. This problem is eliminated by forming IRON (Iterative Repeatable Runout Nulling) profile tracks from the initially pre-written servo tracks, where the IRON profile tracks are effectively tracked as concentric circular tracks and generate no PES. The IRON profile is formed by an iterative method that starts with the measurement of the PES of one of the pre-written tracks and iteratively forms a new track profile that is effectively circular.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.