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 Post subject: here's my theory to getting data back
PostPosted: March 16th, 2011, 13:22 
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Joined: March 13th, 2011, 15:29
Posts: 70
Location: Greenville, MI
I've got a drive with bad sectors. it hangs when windows trys to mount, eventually it does after 20 minutes.

I've tried get data back, r-studio, ddrescue and a couple others. Here's my theory. Format the drive, not quick but a full format where it goes and repairs any bad sectors, then run gdb and recover anything not in bad sectors :idea: .

let me know what you think of this idea

thanks,

Dave


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 Post subject: Re: here's my theory to getting data back
PostPosted: March 16th, 2011, 13:26 
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Joined: March 7th, 2009, 12:43
Posts: 1091
Location: Angel Data Recovery
Dave48838 wrote:
I've got a drive with bad sectors. it hangs when windows trys to mount, eventually it does after 20 minutes.

I've tried get data back, r-studio, ddrescue and a couple others. Here's my theory. Format the drive, not quick but a full format where it goes and repairs any bad sectors, then run gdb and recover anything not in bad sectors :idea: .

let me know what you think of this idea

thanks,

Dave


Bad idea .
Will not help , more - will exacerbate .

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 Post subject: Re: here's my theory to getting data back
PostPosted: March 16th, 2011, 13:26 
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Joined: February 27th, 2009, 3:26
Posts: 1721
Location: French Polynesia Tahiti
NO very bad idea on this one. What you need to do is clone this HDD to an new one. Then you can get your data back on this one working from your clone on it. You can dry ddrescue or the dd_rescue on this one they both can handle some bad sectors on this software.

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 Post subject: Re: here's my theory to getting data back
PostPosted: March 16th, 2011, 13:39 
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Joined: March 13th, 2011, 15:29
Posts: 70
Location: Greenville, MI
it was just a thought, what do you mean will exacerbate?

With what I have available to me, I can't help but think that this would work. I mean I don't care about the first letter of every file being turned into a $.

a full format would repair all bad sectors, then gdb would recover any files not in those bad sectors. Help me out here, what won't work about this theory?



DR-Kiev wrote:
Dave48838 wrote:
I've got a drive with bad sectors. it hangs when windows trys to mount, eventually it does after 20 minutes.

I've tried get data back, r-studio, ddrescue and a couple others. Here's my theory. Format the drive, not quick but a full format where it goes and repairs any bad sectors, then run gdb and recover anything not in bad sectors :idea: .

let me know what you think of this idea

thanks,

Dave


Bad idea .
Will not help , more - will exacerbate .


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 Post subject: Re: here's my theory to getting data back
PostPosted: March 16th, 2011, 13:49 
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Joined: August 12th, 2008, 13:11
Posts: 3235
Location: USA
What are you thinking of using to "full format"? Windows?

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 Post subject: Re: here's my theory to getting data back
PostPosted: March 16th, 2011, 13:51 
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Joined: March 7th, 2009, 12:43
Posts: 1091
Location: Angel Data Recovery
Dave48838 wrote:
full format would repair all bad sectors,


Who sad this BS ? (sorry for ladies :oops: )

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 Post subject: Re: here's my theory to getting data back
PostPosted: March 16th, 2011, 14:02 
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Joined: March 13th, 2011, 15:29
Posts: 70
Location: Greenville, MI
Microsoft, and my theology supplied me with this BS

http://support.microsoft.com/kb/302686 first paragraph under more info.

a full format would look over the whole drive, find the bad sectors, mark them as bad, then the HDD wouldn't use those sectors. After that, running gdb would recover anything not in those bad sectors.

let me know your ideas on this,

Thanks,
Dave


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 Post subject: Re: here's my theory to getting data back
PostPosted: March 16th, 2011, 14:23 
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Joined: May 6th, 2008, 22:53
Posts: 2138
Location: England
Dave48838 wrote:
Here's my theory. Format the drive, not quick but a full format where it goes and repairs any bad sectors, then run gdb and recover anything not in bad sectors :idea: .

let me know what you think of this idea

Another vote from me (to add to those from DR-Kiev, pohere and I think drc :) ) recommending against this idea. Depending on what exactly you plan to use to do the "full format", this is either a bad idea (overwriting some sectors which might be useful for recovery), or it's complete suicide for the data. I'm worried that you have read some internet mis-information about what a full format does. :(

Dave48838 wrote:
I've tried get data back, r-studio, ddrescue and a couple others.

IMHO, if you want good suggestions, you need to be more open about exactly what happened. Saying that you tried them, but nothing more, doesn't give anyone enough info to then help you further. :(

My experience is that ddrescue, when used correctly (success improves with practice & experience), as part of a well-prepared overall approach and not with the "problem drive" USB-attached, is very successful at cloning what data can be read - within the limits of any software-only tool. Only after that, would you use logical recovery software like gdb on the clone from ddrescue.

Just my £0.02


Last edited by Vulcan on March 16th, 2011, 14:26, edited 1 time in total.

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 Post subject: Re: here's my theory to getting data back
PostPosted: March 16th, 2011, 14:25 
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Joined: January 15th, 2008, 11:06
Posts: 1419
Location: Providence, RI. Boston, MA USA
Format won't fix your bad sectors.

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 Post subject: Re: here's my theory to getting data back
PostPosted: March 16th, 2011, 14:48 
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Joined: February 27th, 2009, 3:26
Posts: 1721
Location: French Polynesia Tahiti
There is a way to fix your bad sectors and this one can be accomplished in MHDD. But in doing this one you lose data forever - gone - bye bye ---- You can never get it back. Windows format will not do this one for you at all.

You have a chance if you clone your HDD to another one and work from clone on this one. If you are so sure that your idea :idea: can work for you do it. Why sit here and argue on this one. If you have this one set up in your mind and can see this one working for you then please do this and see what happens. But in the end when it does not work do not come here and say wow it is not working and now I have a HDD with bad sectors that I formatted and lost all my data on what can I do to get it back. It is that simple. You either take good advise from people who do this all the time or your follow your own advice and see where you get on this one.

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 Post subject: Re: here's my theory to getting data back
PostPosted: March 16th, 2011, 16:31 
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Joined: August 12th, 2008, 13:11
Posts: 3235
Location: USA
Dave48838 wrote:
a full format would look over the whole drive, find the bad sectors, mark them as bad, then the HDD wouldn't use those sectors

What actually happens is that the filesystem stops using these sectors, not the hard drive. No format utilities have the ability to tell the hard drive to stop using particular sectors. The hard drive typically makes this decision internally. Additionally, you would overwrite a significant portion of the structure that the filesystem uses to locate and organize your files. Sure this can be worked around by utilities to some degree, but you would probably end up with a lot of loose files with lost names and/or directories.

Also, depending on which version of windows you are using, full format will even overwrite the entire volume. Obviously this would be bad for data recovery. :mrgreen:

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 Post subject: Re: here's my theory to getting data back
PostPosted: March 16th, 2011, 17:03 
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Joined: April 5th, 2010, 23:02
Posts: 89
Location: Winder, GA
Dave48838, maybe I'm missing something obvious here but using this logic why not just run a chkdsk /r ? Actually, "using what is available to you" why not just download mhdd and scan the drive having it remap all the bad sectors? There are a ton of ways to map out the bad sectors and regain Windows control of the hard drive (assuming the bad sector count is manageable) without running a format.


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 Post subject: Re: here's my theory to getting data back
PostPosted: March 16th, 2011, 18:26 
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Joined: May 6th, 2008, 22:53
Posts: 2138
Location: England
@Dave48838: Your post now showing 21 mins before my previous post, wasn't there when I replied (it must have been held in the moderation queue). Now that it has appeared, I'll add a couple of comments:

Dave48838 wrote:
Microsoft, and my theology supplied me with this BS

I know you're being sarcastic, but some of that document is BS!

Dave48838 wrote:
http://support.microsoft.com/kb/302686 first paragraph under more info.

That document is poorly written, ambiguous, and has a specific limitation (it applies only to WinXP and earlier - see below). In one respect the article is actually wrong, where it says:

Quote:
When you choose to run a regular format on a volume, files are removed from the volume that you are formatting

For the version of Windows that they mention (WinXP), my reply to that statement is simply: MS - you're wrong; the files are not removed! :lol:

Rather than me needing to clarify that article further, drc has kindly done that (thank you!). As he explains, running a "full format" would not "repair" any sectors, as you initially suggested - it just marks any unreadable sectors as bad (and therefore not to be used) in the filesystem metadata. As a minimum, a "full format" would still overwrite that metadata which you really do not want to do.

Furthermore, that document relates specifically to WinXP. You will note that drc confirms my comment about other Windows versions (e.g. Win7 & Vista) deliberately having changed to doing an overwite during a "full format", which as I said, would be bad. :(

http://support.microsoft.com/kb/941961

Dave48838 wrote:
a full format would look over the whole drive, find the bad sectors, mark them as bad, then the HDD wouldn't use those sectors.

Even assuming that you're using WinXP (I don't see where that has been stated yet), so that a "full format" wouldn't overwrite the whole disk, as a minimum you would still lose valuable filesystem metadata, making full recovery less likely (due to the effects of fragmentation).

I hope this helps to explain (along with all the other advice you're seeing here) why you're getting such a negative reaction to your idea. But in the end, it's your data, your risk, your choice. I hope you make the right decision about which plan to follow. :)


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 Post subject: Re: here's my theory to getting data back
PostPosted: March 17th, 2011, 7:17 
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Joined: December 12th, 2010, 9:50
Posts: 121
Format will overwrite file system parameters like FAT /MFT etc. If you format within windows System Volume Information /Recycle bin folders are created. File system like Fat16 is vulnerable for format .I think its neither wise or profesional idea


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 Post subject: Re: here's my theory to getting data back
PostPosted: March 17th, 2011, 8:15 
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Joined: October 24th, 2009, 8:16
Posts: 282
Location: Gdansk - Poland
Do not format it.
Make a clone. Use DMDE, hdclone or ddrescue.

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 Post subject: Re: here's my theory to getting data back
PostPosted: March 17th, 2011, 8:40 
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Joined: March 17th, 2011, 7:39
Posts: 2
Location: Ireland
I don't want to create a new topic so will spoil this one and ask my own question.
Firstly, answer on topic- if there's a badly damaged disk, you won't be able to do format. It's good practice to make an image of disk if possible and work with it.

Now the question.
Just imagine hard drive without bad sectors, but with messed up partition table. Let's say one of the partitions is missing, administration tools shows this space as unallocated. Lets say that this partition can't be recovered by any partition tool. What do you think about such approach:
1. Create partition in empty space and leave it unformatted.
2. Start Recuva and get as much data as possible. I can't confirm it now, but it should be able to recover data from unformatted media.


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 Post subject: Re: here's my theory to getting data back
PostPosted: March 17th, 2011, 8:41 
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Joined: February 19th, 2011, 11:05
Posts: 358
Location: Toronto
1. A full-format (unlike a quick one) will overwrite all data remaining on the disk with 0s. That will make data recovery impossible.
2. In R-Studio, it's not necessary to clone the disk. You may create a compressed image of the disk reducing the size required to store the disk data. Then the data can be recovered from that image as from the original disk. Image compression doesn't seriously decrease data reading speed.

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 Post subject: Re: here's my theory to getting data back
PostPosted: March 17th, 2011, 11:57 
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Joined: May 6th, 2008, 22:53
Posts: 2138
Location: England
Alt(R-TT) wrote:
1. A full-format (unlike a quick one) will overwrite all data remaining on the disk with 0s. That will make data recovery impossible.

That is only true with some OS's - not with all. I think it is important and relevant to the original question, to make that point clear.

Alt(R-TT) wrote:
2. In R-Studio, it's not necessary to clone the disk. You may create a compressed image of the disk reducing the size required to store the disk data.

Such a compressed image, is just a compressed clone written into a file - it's still a form of clone IMHO. :)

Also anything which is not a pure (uncompressed) clone is less "vendor / software neutral", and makes it more difficult to use anything other than your company's software to then read it. Therefore to allow the widest range of logical recovery software to be used later, a pure clone (whether written into a filesystem or raw disk) still has some advantages IMHO.


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 Post subject: Re: here's my theory to getting data back
PostPosted: March 17th, 2011, 11:59 
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Joined: August 12th, 2008, 13:11
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Location: USA
IMO NTFS sparse files are superior for image storage

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 Post subject: Re: here's my theory to getting data back
PostPosted: March 17th, 2011, 12:30 
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Joined: March 7th, 2009, 12:43
Posts: 1091
Location: Angel Data Recovery
Alt(R-TT) wrote:
1. A full-format (unlike a quick one) will overwrite all data remaining on the disk with 0s. That will make data recovery impossible.


I agree with Vulcan.
In most file systems, full-format not much different from quick-format.

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