Patent ID: 6181652
Filing Date: 2001-01-30
Classification: G11B

Abstract:
In an apparatus for data recovery from rotating data storage disks having varying degrees of hole eccentricity and track eccentricity, a method of reading each disk at a speed suiting the particular hole eccentricity of that disk, which method comprises:(a) driving a data storage disk at a first disk eccentricity check speed;(b) making a first measurement of the hole eccentricity and track eccentricity of the disk in rotation at the first disk eccentricity check speed;(c) driving the disk at a second disk eccentricity check speed which is higher than the first disk eccentricity check speed;(d) making a second measurement of the hole eccentricity and track eccentricity of the disk in rotation at the second disk eccentricity check speed;(e) ascertaining the hole eccentricity of the disk by subtracting the first measurement from the second measurement; and(f) determining a matching speed of rotation for reading the disk on the basis of the above ascertained hole eccentricity thereof.