Patent ID: 6281676
Filing Date: 2001-08-28
Classification: G01R,G11B

Abstract:
A method for the detection and classification of defects on data storage surfaces of rigid disk drives having at least one data surface which is confronted by a transducer head for writing data to and reading data form the surface comprisingpartitioning the disk data surface into cells including a selected number of contiguous tracks in a radial direction and defined by sector boundaries in the circumferential direction;sub-sampling by writing and reading a selected minority of tracks distributed over the data surface to identify surface defects;storing the number of defects that occur in each cell;analyzing the stored defect numbers to determine whether defect clusters exist in the form of a plurality of contiguous cells each containing a number of defects exceeding a threshold number;indexing to a second data surface of a disk drive with multiple data surfaces; sub-sampling by writing and reading selected tracks on such second data surface to identify surface defects and storing the number of defects that occur in each cell, wherein the steps of indexing to another data surface, sub-sampling and storing defects are repeated until all data surfaces have been sampled;storing of the location and size of clusters found on each data surface which exceed a predetermined number of cells in a largest cluster table; andscanning each track within a cluster to obtain further verification of the defect status within the cluster.