In the days of old, I remember getting drive errors, but it seems that modern drives never report errors, but instead make a best effort to return you something. I recently had a hard drive fail, rather badly, but while it was failing it never reported errors (or at least WinXP never surfaced those errors). I knew it was failing because programs began behaving badly and it finally died during boot. When I attached the drive to another machine to read everything off, I was able to copy everything (after some permissions flail) and it did so without error, but the actual content was damaged as archive testing proved. The manufacturer's drive testing software determined there were no errors but SpinRite hard stops while scanning the drive. I'm beginning to wonder how much of the instability of modern software is attributable to modern hard drives.
So the question is, are hard drives now just lying to us? Specifically, when faced with an unreadable sector, are modern drives prone to return corrupted data without reporting it as such to the OS?
Best Answer
Yes, newer hard drives lie to us. You can usually monitor those lies with SMART.
I think it has to do with the information density on typical platters. The designers assume that there will be flaws in the platters, and design the firmware around that - if a sector fails, it's automatically re-written and no data is lost. It's only when the drive runs out of spare sectors that the typical OS will notice, and at that point your data is at risk.
So, I guess the moral of the story is use something like smartmontools to monitor the lies.