<div>On 4/17/06, Alan McKinnon <<a href="mailto:alan@linuxholdings.co.za">alan@linuxholdings.co.za</a>> wrote:<blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;"> On Monday 17 April 2006 00:22, Yorvik wrote: > Gary W. Swearingen wrote: > > I'll propagate a rumor I heard: Use of "badblocks" has been > > obsolete since drives started to remap their own bad blocks many > > years ago. You won't find bad blocks until after your drive has > > found so many that it's better used as a doorstop. > > > > I beg to be corrected by someone with real knowledge. > > I was told a couple of years back, that if you can find bad blocks > with 'normal user software' the drive has had it and may as well be > chucked. That's not true. There's many urban myths surrounding disks, and this is one of them. > Personally, I can remember when harddisks had labels on them > listing the bad blocks. Those were MFM drives. Drive manufacturers soon got fed up with the support calls from users as to why they shipped faulty disks - ALL drives have errors. Solution - disguise the errors. Modern drives keep a small percentage of space free for bad blocks and as the firmware picks up failing sectors, it remaps their location into this unused space. The whole cyclinder/sector scheme is a pure abstraction anyway, so this works well. When you run badblocks and pick up a few errors, all you are doing is beating the drive firmware to the same job. When you find it with user software, it means that the firmware has given up trying. Reading and writing to a disk is a tricky job (almost but not quite entirely unlike reading and writing to RAM), and the firmware is limited in what it can get the heads to do. The end result is that it gives up easily, which opens up a nice market for third party software. This is most of what disk data recovery is about. Spinrite is a good example and <a href="http://www.grc.com">http://www.grc.com</a> explains it all nicely as long as you can read past Steve Gibson's hyped opinions. What you should be worried about is the *rate* at which bad sectors are being produced. Once this passes a certain well-defined amount, then the drive is becoming statistically more likely to fail. This is what SMART is all about. So while what you were told is not completely wrong, it's over simplified by a very big margin </blockquote></div> so does this mean I shouldn't bother in testing my hard disks for its already taken care of?