Bad disk sectors

davidbrit2

davidbrit2

Licensed Computer Geek
What (free) software exists that will scan a disk for bad sectors, and mark them as such so the operating system will avoid them? Part of my disk has been acting fishy lately, and it made some really freaky sounds when the system crashed once, so I think there's a bad sector or two. My filesystem is okay, but I need to mark these sectors before all hell breaks loose.
 
This'll probably be an unpopular response.

First of all, if you have bad sectors, your hard disk is probably on its way to failure. Obviously, it would be a good idea to CONSIDER a new hard disk.

However, I've had the same problem with mine and when you consider that every new hard disk purchased technically has bad sectors on it that were concealed by doing a low-level format at the manufacturer's before the unit is shipped, you should conclude that doing another low-level format on a dying drive will restore it to working order, in most cases to perfect shape.
 
I'm not too worried about the drive failing yet, since my iBook is barely over a year old. The weird head behavior was just a complete fluke caused by an OS installation gone horribly, horribly wrong.

The funny thing is that I know which file houses the bad blocks. So until I find something to mark them on the disk, I'll just chmod the file to 000 and store it for safe keeping.
 
My own hard drive problems, as much as people would love to blame my IBM drive being a 75 GXP that was bound to fail anyway, was due to a program called Diskeeper kicking on while I was playing Neverwinter Nights.

The program auto-defrags when it deems it necessary. It deemed it necessary during a game and froze that game. When I restarted the comp, the noise you spoke of came up and frankly scared the living piss out of me.

Andre
 
Yikes. I'll remember not to use Diskeeper.

Anyway, I tried repairing the disk with Drive 10, which claims to be capable of marking bad sectors. When it hit a bad sector during the surface scan, it just paused for a few seconds, and aborted the test. Afterward, in the report, it told me the surface scan failed. Of course it failed, dummy, now repair it! Rrrgghh... Did I miss a step, or something? I'm repairing the partition while it's unmounted, so it shouldn't have any trouble.
 
Too many bad blocks or sectors, surface scan fails, back up if you need to while you still can. Try to find a disk utility that REALLY does a low level format. Get ready to replace the hard drive. Less than One Year since purchase, it's still under Apples warranty, unless you purchased AppleCare or other extended warranty. HDs go bad early sometimes....:cool:
 
Again, I'm not worried about the physical condition of the disk. The problem seems to be quite isolated, suggesting there isn't really any media damage at all, but rather just some junked up sector headers. To a kernel, that would look exactly like a bad disk.

And for the record, here's the error that's reported on the console when I try to read an affected file from single user mode:
Code: 
disk0s10: 0x8 (UNDEFINED).
I assume this means "sector not found."
 
I think the only way to fix bad sectors is to do a low-level format, or if your drive is SMART compatible, plug it into a PC and use some SMART analysis software on it...(it wouldn't damage the drive if you plugged into a PC, only there might be some Windoze files on it afterwards - nothing to damage the drive, just delete the extra files when you pop it back into the iBook from OS 9/X. This way you could be sure if impending drive failure is on the horizon - sorry to keep hammering that in :D). I'm next to positive I've seen Norton fix bad sectors when you do a full disk scan, and I'm fairly certain Apple's OS 9 (and ONLY OS 9) Disk First Aid tool will do it. I'm pretty sure DFA won't do it in OS X because DFA in OS X is just a GUI for fsck, which doesn't do very extensive fixing (in my experience anyway).
 
Whoo... I think it's fixed...

Norton Utilities was able to map out the bad sectors, and after a repair time of double-digit hours, everything seems to be back in order. About 90 KB of the disk got blown away, but I can live with that.
 
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