The ECC is not the low level data. The servo tracks are. I bet there are start of track/sector header marks also. I believe a low level format will not re-write the servo tracks. Some drives reserve 1 side of 1 platter for servo data. Others mix the servo data with user data. I don't know the full details, just tidbit I have read over the years. If your drives were cooled better than most, that may explain why you did not have the "substrate had heat expansion issues". Just a guess. If the problem was a firmware issue, why didn't IBM release a firmware update? You said: "the firmware theory is supported by the fact that many deathstars performed perfectly well for many years" Are you saying some drives had good firmware, while others had bad firmware? Otherwise, I don't understand your logic, since a drive not failing does not prove a firmware bug. Guy -----Original Message----- From: linux-raid-owner@xxxxxxxxxxxxxxx [mailto:linux-raid-owner@xxxxxxxxxxxxxxx] On Behalf Of Mark Hahn Sent: Thursday, December 02, 2004 10:37 PM To: TJ Cc: linux-raid@xxxxxxxxxxxxxxx Subject: Re: Good news / bad news - The joys of RAID > not. It is my belief that formatting was inneffective at fixing the drive > because the cross writing probably hit some of the low level data, which the > drive cannot repair on a format. the ecc *is* the low-level data. without performing a controlled experiment that recreates the power-off scenario, there's no way to distinguish a block whose media is actually bad from one whose ecc fails because the ecc is bad. the firmware theory is supported by the fact that many deathstars performed perfectly well for many years. I have at least one that lasted for 4+ years, and was powered off only a few times, and all of those cleanly. - To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html - To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
