[Severed Hand of Skywalker]

A friends hard drive has bad sectors as reported by utilites and my own observations. I THINK that if he does a low level format it will see the bad sectors and mark them not to be used and the drive will be ok after that.

True?

[Eug]

I don't think too many drives these days really have a true low level format that can be done by the user.

However, you can get drive utilities from some of the drive makers that reanalyses the drive and marks off the bad sectors permanently.

OTOH, most of the time if the drive is starting to get bad sectors I'd consider replacing it before its too late, unless it's a scratch disk or something. ie. Sometimes the drive is simply on its way out, and it might not be a good idea to chance your important data to it.

[Severed Hand of Skywalker]

Well with OSX 10.2.3 there is an option do do a "Zero all data" and in OS9 there has always been a "low level format" and "Zero all data". That should do it right?

Doesn't just about all disk have some bad sectors, I know Zip disks do and a long format will find them and use the small extra space on a Zip to recover for the lost space.

[Eug]

Zero-fill does not mean it's doing a true low level format. I don't know however if OS X's utility will somehow instruct the drive to remap the bad sectors. I'd be interested in finding out more about this. But my undereducated guess is no.

Similarly, I don't think it's possible for OS 9 to "low level format" a modern IDE hard drive at all, despite the presence of such an option. It sounds like it might be some drive utilities and zeroing the drive yet again, or does it have other diagnostic capabilities too? I dunno.

One wrench in the works though re: those drive utilities from the manufacturers: Most are PC based. I had forgotten this point, since the times I've had to do this sort of thing have always been on the PC side, since I've only had Macs for 1.5 years.

EDIT:

Low Level formatting

The gist of the article is that no current hard drives can be low level formatted at all by the end user. So OS 9's low level format feature would do not be doing what it seems to say it's doing.

I would still be interested to know what kind of stuff these OS 9 and OS X utilities can actually do though. Anybody know for sure? I haven't used OS 9's but it sounds like all OS X is doing is a zero-fill, as the name suggests.

[Severed Hand of Skywalker]

I found this on Apples site, not sure it answers much though:

http://docs.info.apple.com/article.h...us%7C162243176

[Eug]

Originally posted by Severed Hand of Skywalker:
I found this on Apples site, not sure it answers much though:

http://docs.info.apple.com/article.h...us%7C162243176

Ah I see:

"ATA (IDE) drives internalize tracking and sparing of bad blocks. Drive Setup and ATA drivers thus have little control over this process. Which is why the low-level format option is dimmed when initializing an ATA (IDE) hard drive. Reallocation (sparing) of bad blocks that the ATA drive tracks will occur when the block is subsequently written to. Thus the best way to force the drive to reallocate bad blocks is to initialize using the write zeros feature. Use Test Disk to verify surface integrity only. Given this strategy, there on occasion may be a need to initialize using write zeros, verify using Test Disk and if any errors occur, attempt to reinitialize using write zeros again."

So basically its saying that the software can't remap the bad sectors on the drive, but running it will may make the drive remap the bad sectors itself. So I guess you could try running it and see what happens.

I do know however, that merely trying to write to a bad sector doesn't always force a remap. I've had some drives keep trying to write to same bad sector. It would work some of the time but the problem was that the drive would stall there temporarily until the write worked. Basically made the system slow to a crawl. The true remap didn't work until I ran one of those drive utilities from the manufacturer. But it might just have been with that model or something I dunno.

But like I said, why don't you just try it and see what happens, esp. if the drive is partially hosed anyway?

[Severed Hand of Skywalker]

the drive is on it's way out for months as far as I know.

So IF we run this OS9 utility where is the bad block info stored? When we install OSX and IF it reformates the drive on the install will the bad block data be lost or is it held in some sort of Hard Drive ROM?

[Eug]

Originally posted by Severed Hand of Skywalker:
the drive is on it's way out for months as far as I know.

So IF we run this OS9 utility where is the bad block info stored? When we install OSX and IF it reformates the drive on the install will the bad block data be lost or is it held in some sort of Hard Drive ROM?

On its way out for months? Sounds risky to me.

It might just be worth spending the CAD$110 to get a 30 GB 7200 rpm drive (or whatever).

To answer your second question: The bad block data will be lost.

[Severed Hand of Skywalker]

Ya thanks for your help man. I am getting him to trash the drive and get a new one.

Now we just need to find a way to backup the data on the drive now that is giving us errors.