2yr old 400Mhz TiBook Bad hard drive blocks
 

In all my experiances which isnt too many, hard disk bad blocks usually grow. Thus when I discoverd that my 2yr old TiBook had bad blocks I was concerned that soon my hard disk would be useless. Can anyone tell me why the drive should have bad blocks anyway (media error?!?!?) and is it likely to continue growing. After the initial scare I am backing up constantly so I spose I'll be ready for the eventual destruction of my drive. Can I slow town its demise or do I just have to wait it out. If I am buying a new drive can I buy a standard 2.5" HDD and what brand would people recommend. Please post any other experiances with bad blocks or ways of preventing them in the firat place. Also does sleep mode lock the heads of a PB and could slight bumps while in sleep cause dud blocks
thanks

One of the good disk repair tools can help you out with bad blocks without having to re-format. Or, you may want to back up your data, and re-format your HD, that process WILL map out the bad blocks and prevent the system from writing to those blocks. Bad blocks accumulate over time. Windows seems more sensitive (part of the need to re-format a Windows HD from time to time) but Mac HDs also accumulate these bad blocks. Nothing you can do to prevent this, and re-formats do not always help, but it maybe worth a try (of course, you will then need to reinstall everything, you lose everything when reformatting.) So, you lose time, but your HD does not necessarily need replacing yet.

Pretty Much Any 2.5 Drive will work
 

Pretty Much Any 2.5 Drive will work:

I suggest an external Firewire 3.5 Inch HD for Backup and Carbon Copy Cloning of your System.....

3.5 Inch Drives are Cheaper and Faster.

After you Clone your System, Reformat the Drive and Restore from the Clone.

i would not continue to use the drive with bad blocks.

i'd backup and do a low level format.

that will attempt to spare the bad blocks. if you can do this successfully, i think you'd be safe to continue to use the drive

Do OS X Utilites allow for low-level formats? I know Joel can do it with/in OS9, but what about those machines that cannot boot into it?

i bet Disk Utility will do a low level format, tho i don't have any way to test that at the moment.

and even if it can't, you can always use Firewire Target Disk Mode to connect to an OS 9 booting machine.

I've never found anything about low level formatting in Disk Utility. And Target mode only works on laptops, correct? Maybe just newer machines. Anyway, low level format seems to be an odd thing for Apple to ditch. Although with the size of hard drives today, a low level format on a 200 gig disk would take a mindbogglingly long time!

Petey, you lose your bet. No Apple-supplied MacOS drive utility has ever performed a true low level format on an IDE HD, only a standard erase, with an option to write zeroes to all blocks during formatting. The older SCSI HDs did allow true low level formatting, and that option was available from most SCSI drive utilities, but in most cases, only the manufacturer has access to utils for true low level formats on IDE HDs. There have been some third party utils that provide a form of low level format in name only, but actually is a write-zeroes to all blocks, (which is the option that can take hours) Writing zeroes is not the same as a low level format. (Very few PC utils do a complete low level format, drive manufacturers do not recommend this.)

DeltaMac,

Perhaps my terms are wrong.

I am uneducated on the differences between low level format and write zeroes format.

However, I've done some type of time intensive, bad block correcting format using Drive Setup in OS 9. This type of format attempted to spare bad blocks, and is what I was recommending to the original poster.

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Yellow,

Target mode should work on all machines Apple has shipped in the last several years. All 'New World' machines, I believe.

And while a time intensive, bad block correcting format may take overnight on a 200GB drive, it's still the only way to deal with bad blocks for the original poster.

Ah, I tried Target mode on a bubble iMac and it failed (much to my dismay), the only others I've tried it on were powerbooks and they all worked. Nice to know that new macs should work.

I agree that low-level/zeroing is the only way to get rid of bad blocks on a drive. Last time I did that on an 80 gig drive it took 14 hours or so.. *shudder*

hmm, you can't get rid of bad blocks, the drive hardware detects a crufty location on the disk substrate media and merely maps them out of the allocatable block map so they can't be referenced.

and there's a school of thought that low level formatting is going to zero this map so the drive has to start finding bad blocks all over again, hitting them, moving the dust around, creating more bad blocks.

salvage your data and if the drive is suspect, get rid of it rather than try and salvage it.

so if it's your drive and you find bad blocks...

you'd recommend simply trashing the drive?

or continuing to use it if a 'write zeroes' format is able to successfully spare bad blocks and then pass a read test?

ATA Drives are not supposed to be Low Leveled
 

RE: ATA Drives are not supposed to be Low Leveled:

The Drives Controller is supposed to Map out bad Blocks on the Fly.....

Anyway if the Drive is Suspect you should replace it...

or to put it another way...
 

define 'suspect'.

how to detect bad blocks?
 

I'm coming in late to this thread - but could you please tell me how you detected the bad blocks on your drive?

all drives get bad blocks. it's part of the technology in the hw to map them out. if a drive starts to flake considerably, it may be just time to cut and run as further futzing could exacerbate the situation accelerating inevitable failure.

a common practice is to get a new drive and re-commission the squeaker to be a hot backup until it fails hard. then rotate.

yeah, hayne, i forgot to ask that up front, but dint want to start the "how to" jihad.

Re: or to put it another way...
 

well, "media errors" could be serious, and if their occurences increase, it's a bad sign.

(?)
 

ok. lemme see if i got this:

- all drives get bad blocks, but normally the hard drive controller spares those blocks, invisibly to the user.

- if a drive utility reports bad blocks, this is evidence that the hard drive controller is UNABLE to spare the blocks. which means the drive is no longer reliable, end of story.

- doing a 'write zero' format is a waste of time.

Re: (?)
 

that's about right. if a drive util reports bad blocks, something is wrong because the drive has failed to map out the bad blocks. so, either the drive is spotty or old/inferior and should be re-commissioned to some other duty until its MTBF (mean time between failure) is realized.

That is not quite correct.

Most modern drives have sufficient quality such that they generally do not get bad blocks.

Bad blocks should be a very rare occurence.

Yes, the hard drive should map them out when they occur.

No, detecting bad blocks that the drive has not mapped out is not necessarily indicative of a bad hard drive. Depending on use, the block may not have been read or written to by the drive, and thus will be detected as bad by utility software forced to examine the block.

Yes, if bad blocks are detected it may be indicative of a failing or unreliable hard drive. However, because bad blocks should be very rarely experienced, it may also be very possible to reformat the drive and thus map out bad blocks, continuing to use the drive safely thereafter. Be cautious and understand what you are doing if you go this route, there is some risk involved.


Just to be clear:

BAD BLOCKS ARE NOT COMMON AND SHOULD TYPICALLY NOT OCCUR USING MODERN HARD DRIVES.


Even if your hard drive is successfully mapping out bad blocks, the fact it is doing so is an indicator that the drive is failing and may become unreliable.

Having had some experience over the last 12-14 yrs, mostly working as a PC service tech, I have had occasion to run HD factory software which shows mapped-out bad blocks. I have yet to see (as recently as 2 weeks ago) any HD with zero bad blocks. All test with recorded (mapped-out) bad blocks of varying degree. (Small actual numbers, to be sure) The fact that ou don't see reported bad blocks through the operating system is a good sign, that means the HD is doing its job of mapping out bad blocks automatically. Stating that bad blocks are rare is not quite true. What is quite rare is the operating system actually reporting bad blocks.

madness ensues.

drives ship with bad blocks. nature is not particularly interested in reality.

[edit: what deltamac said]

I thought this whole thread started
 

I thought this whole thread started with Bad Blocks that were OS Visable.

If they were not OS Visable we have all been talking/ errr writing way to many Sonnets.

Where does anything that I posted contradict that?

Yes, drives ship with bad blocks mapped out by hard drive formatting at the manufacturer.

The discussion was about new bad blocks arising subsequent to that.

Sorry if that was not clear to you from my post and the topic of discussion throughout this thread.

Nowhere I thought you Post was Elegant
 

Nowhere, I thought you Post (2nd to last) was particularly Elegant and Accurate:
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It was the comment made by someone (maybe Delta Mac) that the OS of the End user in ? had reported no bad Blocks.
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And thus we are all having more fun then should be legally allowable solving A non problem.
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That said we all provided the Sagest Advice we could for someone with bad blocks in General.

Ah, but Madagascar is pure serendipity!

in Madagascar, they fix bad blocks by rubbing peanut butter on the hard drive platters.

Well, all the real secrets are revealed now!

in Mozambique, they take HD's with only a single bad block, and mash them up with corn meal to create their tasty national dish - the ferrous frittata. this yummy meal is high in the nutrients iron, bauxite, and ribbon cables.