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TOPIC: 1 Bad Block?

1 Bad Block? 29 Dec 2012 23:19 #3485

Hi MM3,

Happy New Year to you!

Another program called "Drive Genius" (a drive integrity checking and repair program similar to TTP) during a Smart Test reported 1 Bad Block and says:
You have one bad block on your Hitachi HD. Back up and format as soon as possible.

I'm running a TTP Suite Test on my internal Mac drive in a couple of days.
If the report by TTP also shows a Bad Block, would you recommend:
1) reformatting the HD and reloading from SuperDuper.
2) Leaving the HD as is and just boot from my SuperDuper drive until I can buy a new computer (out of the question right now).
3) Work off the current internal HD but stop Super Duper from backing up until I can get a new computer.

A couple of other questions:
a) Can a bad block corrupt my data on the Mac HD?
(In which case the SuperDuper drive would also be corrupted.)
b) Is there a test or action that TTP does that deletes the bad block that wouldn't require me to reformat my working drive? One that moves the data and deletes the bad block?

I'm also reading here:
www.micromat.com/index.php?option=com_ku...d=3456&Itemid=0#3475
that:
The drive may have developed a problem with the controller, in which case putting the mechanism in a new enclosure will solve the problem. Most kernel panics are hardware related.

d) What is a "controller"?

Thanks MM3!!!
iMac 2.66 Ghz Intel/Snow Leopard
4 GB RAM/TTP 6
Website: www.richievitale.com
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Re: 1 Bad Block? 29 Dec 2012 23:43 #3486

A bad block can cause many different types of maddening problems, because the data in the block cannot be read. If the bad block contains part of a file, the Surface Scan may be able to tell you what file it is. The data in that one block is physically gone, and cannot be recovered. I suggest you run the Surface Scan immediately.

In general, it is not a good idea to reformat a drive with a bad block, because that bad block arose after the drive left the factory, and there is no reason not to believe more bad blocks will arise, assuming that the problem is with the magnetic media flaking off, and not with the disk controller, part of the electronics in the drive. When only one bad block is reported, it is likely that the problem is with the magnetic media, because a bad controller would make many blocks be reported as unreadable, as in the recent case in which over 1,000 bad blocks were reported.

The best thing to do would be to replace the drive promptly. If magnetic media in the disk directory flakes off, you will not be able to copy the files from this drive to another.

This subject is relatively complex. I suggest you read the posting Surface Scan if you have not already done so. In this posting, my own drive from my MacBook Pro Core 2 Duo is discussed. It had one bad block, which made the disk directory unreadable.

Happy New Year! (and may you not have any more bad blocks)
MicroMat Inc
Makers of TechTool
Last Edit: 29 Dec 2012 23:45 by micromattech3.
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Re: 1 Bad Block? 12 Jan 2013 01:17 #3586

TEST

Trying to see why I cannot start a new topic. It goes to a DENIAL page.
His secrets are not sold cheaply.
It is perilous to waste his time.
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Re: 1 Bad Block? 12 Jan 2013 02:37 #3587

I cannot explain that. I will post a new topic called Doctor X's question.
MicroMat Inc
Makers of TechTool
Last Edit: 12 Jan 2013 02:46 by micromattech3.
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1 Bad Block? 12 May 2013 01:20 #4033

If it is a single bad block I suggest testing again with different software. TTPro 6 can report (incorrectly) a single bad block in some cases. Restesting with TTPro 5 found no bad blocks.
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1 Bad Block? 13 May 2013 18:02 #4048

We have seen only one case of a false positive from TechTool Pro 6.

There is the very unlikely possibility that the drive has what is called a marginal block, one which can be read on some attempts and not on others, because of extremely small errors in detecting the start of the block, which is controlled by the drive itself.
MicroMat Inc
Makers of TechTool
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