What are Bad Clusters?

[The DJ]

Can somebody please fill me in on what "Bad Clusters" are? I have an external hard drive that has bad clusters on it. I have tried about everything I could think of to recover them, ran programs, re-formated the drive pulled the partition out and re-loaded everything and it still reads bad clusters are in there. I don't know why. It's an older Maxtor 120 GB drive and for the most part, I thought the drive was failing when it turned out to be that the power supply plug and the usb plugs were not securely seated. Right now the drive only has about 4 kb of bad clusters, it used to have more.

[cscgal]

The data on a hard drive is broken down into sectors. When a small amount of data becomes corrupted, that area of the hard drive becomes unusable. When you format the drive (high level format) the bad clusters are not removed because the format simply knows to skip over the bad clusters. Correct me if I'm wrong, but I think that a low-level (writing zeros) format may correct bad clusters. If it doesn't, it would seem that there is a physical problem with the disk, and nothing could fix that. If there was a problem with the drive's connection to the power supply, it is possible that it got some physical magnetic errors through a power surge of some type.

[The DJ]

I have run format after format on it. I have used the programs in the computer management that is supposed to clear the bad clusters, but that doesn't always work. I have recovered 12 KBs and am now down to 4 kbs but a KB is so miniscule that it shouldn't make a difference on anything should it? I'm operating here with over a terabyte and a half of space over here between 4 computers. This drive is a USB drive that has givien me some difficulties, though I think I have narrowed it down to the power supply not being connected properly. The power supply cord has a transformer in the middle of the line and I think the weight of it sometimes causes the line to loosen a little. I'm taking the approach as long as the drive still works, I'm going to use it. If it's got a bad cluster or a few in there and it ignores them and I can operate without a problem, Great. I just didn't know if they meant that my hard drive is going to die on me or not. It has been operating like this for a very long, long time now, so perhaps it is not all bad.

[cscgal]

Your operating system will make sure not to write to any bad clusters on the disk, so there is no data loss as far as that is concerned. However, if a disk has bad clusters you can't get rid of, it inevitably means a physical problem with the drive itself. Especially since you have over a terabyte of space, I would use the USB drive to backup stuff that you have another copy of somewhere else, and not rely on it for important data - because who knows.

[The DJ]

I have to use a lot of redundant back ups. I have a lot of stuff and CD's & DVD's just can't cut it. The terabyte of space is not one drive it is a a collection of 16 drives. One 120GB drive was the problem. But it's good to know! :lol:

[caperjack]

I have to use a lot of redundant back ups. I have a lot of stuff and CD's & DVD's just can't cut it. The terabyte of space is not one drive it is a a collection of 16 drives. One 120GB drive was the problem. But it's good to know! :lol:

Have you tried Maxtors MaxBlast program to low level format the disk /right the disk to zeros!

[The DJ]

Yes I have but it wouldn't get all of them. I'm not going to sweat the silly 4 kb. I think what most of the problem has been was that I couldn't get the power plug sto stay in the slot. That might not cause the bad clusters but as I saw it, the whole thing was driving me up the walls.

[tekeek]

if you have bad clusters there is two apps that will most likely fix them, if they do not then you have a major issue with your drive and it will be better to replace it. If you keep getting bad clusters then it would be advisable to still replace the drive as that means the drive is on its way out the door. The two apps to use are either SpinRite or HDD Regen. Although SpinRite is the better of the two. Also they do cost. I have yet to find a free alternative that will do what they do. If all the issue is just bad clusters unrelated to potential hard drive failure, these will do the trick. I have used them time and time again.

Here are the links for the two
http://www.grc.com/sr/spinrite.htm
or
http://www.dposoft.net/

[mechbas]

Based on some 17 years of experience read or write errors such as what you've experienced means only one thing, a failing drive and/or floppy disk if it applies.
Better to ditch the hardware than try to correct a worsening prob. It's never worth the effort.

[colemanmia]

A bad sector is a sector on a computer's disk drive or flash memory that cannot be used due to permanent damage, such as physical damage to the disk surface or failed flash memory transistors.