Surface analysis test defect detector for direct access storage device

摘要

A method and apparatus are provided for detecting surface defects in a direct access storage device. Disk data readback sample values are converted to gain error values based upon an identified difference from predefined ideal data values. An error signal accumulator accumulates a summed value of error signals for a current sample and a predetermined number of past samples. Each sequential accumulator summed value is compared with a predetermined threshold value. An error output is generated responsive to each sequential accumulator summed value greater than or equal to the predetermined threshold value, the error output identifying the disk surface defect.