So I placed a magnet near my hard drive... - by kodan50
kodan50 on 24/7/2008 at 17:21
Actually, I didn't realize that I had done so. (The magnet is wrapped around fabric, so it didn't even occur to me that I created an issue) and, wouldn't you know it, the magnet seems to have disrupted some data that I had on the hard drive. I am running some program that states it can try and recover the data. I don't necessarily care about data loss though, as mich as whether or not my hard drive is shot.
My question is, can a magnet cause any physical damage to the hard drive that can render part of it completely unusable, or is the worse that will happen is it will disrupt data and a simple zero fill should fix the drive to be usable? Can a magnet damage any mechanical part of the hard drive that would impare its functionality? It's not a strong magnet, both the magnets involed are strong enough to bind some fabric together, and are rather weak magnets.
theBlackman on 24/7/2008 at 19:05
The surface of the "discs" in the HDD are coated with iron oxide (rust), the data is written magnetically (more or less) which arranges the coating in patterns. Your magnet disrupted the patterns.
If you don't really care, just try a full deep reformat and start over. With any luck, you will have a clean, undamaged HDD to work with.
You have nothing to lose by trying.
Mortal Monkey on 27/7/2008 at 10:31
As far as I know, there are only two ways to damage a HDD permanently with magnets.
* A very strong magnet could bend the platters permanently.
* While the drive is operating, a magnet could cause a head to scratch the coating off a platter at high velocity. Needless to say, conductive metal bouncing around inside your HDD is not a good thing.
doctorfrog on 29/7/2008 at 05:42
Quote Posted by theBlackman
The surface of the "discs" in the HDD are coated with iron oxide (rust), the data is written magnetically (more or less) which arranges the coating in patterns. Your magnet disrupted the patterns.
If you don't really care, just try a full deep reformat and start over. With any luck, you will have a clean, undamaged HDD to work with.
You have nothing to lose by trying.
Conventional wisdom is that drive controllers on desktop machines are nowhere near precise enough to perform a low-level format (if that is what theBlackman is suggesting). You may be taking a drive with a few bad sectors or unreadable partitions and making it just plain unreliable. If we're talking about a full format, go for it.
I'd wipe the partitions, and start anew. Boot with (
http://gparted.sourceforge.net/livecd.php) GParted, use fdisk, whatever. Format the long way, so all the bad sectors are hunted out and marked as unusable. Recovery software is rarely worth the effort and time unless you know exactly what you're looking to recover, and it's irreplacable. Back up the pertinent stuff next time.
I've repartitioned and formatted dozens of times out of sometimes-founded paranoia, and it's something you can literally do with little to no risk, if you already don't care about the data. The disk will be fine, and you'll feel a little more secure about the sectors that are left.
But sweet mercy, back your stuff up. No excuses. Drives are the cost of two tanks of gas these days.
EDIT: Actually, if you really don't trust the drive, take it apart. Hard drives are neat. Make a clock out of it.
theBlackman on 29/7/2008 at 09:06
doctorfrog is correct. Do a full scan and format. The long one, not just a quickie.
I should have been clearer. A complete wipe, scan and reformat should give you a usable HDD.
That is if the data is, in fact, of no consequence at this time.
Fingernail on 29/7/2008 at 10:27
It occurred to me a while ago that keeping my PC right next to my guitar amplifier with its huge speaker magnet was perhaps not the wisest thing. However, it didn't cause any issues for me at the time (well, they weren't that close I suppose, and shielded by the case and the amp itself)
baeuchlein on 29/7/2008 at 12:11
In theory, everything that's possible can happen. This includes anything one can imagine with magnets.
On the one hand, magnetic fields near a hard disk can create several "disturbances" manifesting as errors. On the other hand, sometimes even strong magnetic fields do nothing to a disk.
I once tried to "erase" a floppy disk with two magnets attached to the upper and lower side of the disk, since the disk formatting program exited with a read error before even trying to format the disk. Of course I had to try it three times until the data on the disk was finally disturbed enough for the formatting program to format it. Not very logical, but at least I could format that disk again...
When someone accidentally placed one magnet close to another such floppy disk, the data on the disk was damaged immediately. Some form of Murphy's Law, I guess - whenever one does not want to erase data, it works on the first opportunity. In all other cases you need at least three trials until you have a chance to erase the data.
Furthermore, I have two old HP C2490 SCSI hard disks, and they both have a magnet inside which is strong enough to hold a nail once you drop it onto the appropriate part of the disk's case. Thus, there's a magnetic part inside emitting a considerably strong field, but the disks still operate without fault. Seems to be a part of the stepper motor, by the way.
However, if a magnetic field causes problems, there are several things that might happen.
First, the data on the disk can become corrupt. Usually, it's best to erase the damaged data and replace it with a backup copy.
Additionally, some formatting information can be damaged as well, forcing you to reformat the drive (or partition) in order to get it operational again. Whether a low-level format is required depends upon what data is damaged.
However, in theory it is possible that some of the drive's electronic or mechanical parts become magnetic and prevent the drive from functioning properly. If these parts emit a magnetic field strong enough to disturb the field generated by the drive's magnetic heads, the drive will likely have severe problems reading or writing anything from the disk. Even a low-level format would fail. Since exposure to heat can disturb magnetic materials, as well as strikes applied to the materials, one could try to cook the drive or throw it from a house's roof. Unfortunately, the drive may cease to function at all after this... :ebil:
I would first try to repartition and reformat the drive in question, and if that fails, I would apply a low-level format. If that fails as well, I'd give up.
