Prevention of Hard Errors in Magnetic Files Due to Long Term Degradation
Original Publication Date: 1987-Mar-01
Included in the Prior Art Database: 2005-Feb-01
Hard errors can be due to degradation from "aging", the gradual reduction of signal by the cumulative effect of many small stresses, such as stray magnetic fields, intertrack interference, mechanical or electrical changes affecting track misregistration, chips or scratches in the head. This can be prevented by the periodic reading of all the data to test the quality of the data in the file. If any of the data is below a predetermined quality, a rewrite of the data is done after the recovery in order to refresh the data to full quality. If the rewritten data is not of high quality, the physical sector itself is in question. Thus a warning is issued to the user recommending a reallocation of the given sector.