Wrong Geometry

How to use TestDisk to recover lost partition
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Author
kaxyus
Posts: 8
Joined: 22 Mar 2012, 12:05

Wrong Geometry

#1 Post by kaxyus »

Hi everyone,
This is my first post.
First of all thanks for this amazing software.
I have a problem with a hard disk hitachi 1TB (Model HDT 721010SLA360 - CHS: 16383/16/63 - LBA: 1953525168).
The disc has a single NTFS partition that contains only data and no operating system.
The hard drive, connected to a PCI controller is properly recognized by the BIOS and also by TestDisk, but the disk geometry is wrong.
Inserting the correct parameters TestDisk assigns a different dimension of the disc (8455 MB), much lower than the correct one.
If I proceed with the geometry found by TestDisk detects an error in the number of heads: 16 instead of 32.
If I ask the list of files TestDisk detects only two folders that contain a few gigabytes.
I believe this is due to incorrect geometry detected. What do you think?
How do I insert the correct disk geometry?
Thanks.

User avatar
Fiona
Posts: 2835
Joined: 18 Feb 2012, 17:19
Location: Ludwigsburg/Stuttgart - Germany

Re: Wrong Geometry

#2 Post by Fiona »

Controller of motherboards often convert geoemtry to 255 and 240 heads.
Also it might be depend on your OS.
Linux for example uses often 16 heads.
Infos;
http://www.cgsecurity.org/wiki/Menu_Geometry
That's why a diagnose might be important.
I'd need infos from Analyse, Quick and Deeper Search.

kaxyus
Posts: 8
Joined: 22 Mar 2012, 12:05

Re: Wrong Geometry

#3 Post by kaxyus »

Thanks Fiona,
The operating system is windows XP.
as soon as I get home I will do the check and post it here.
See you soon.

kaxyus
Posts: 8
Joined: 22 Mar 2012, 12:05

Re: Wrong Geometry

#4 Post by kaxyus »

Hi Fiona,
here are the Testdisk screenshots:
16 heads
Analyze(16).png
Analyze(16).png (32.74 KiB) Viewed 11639 times
Quick Search(16).png
Quick Search(16).png (27.7 KiB) Viewed 11639 times
DeeperSearch(16).png
DeeperSearch(16).png (27.32 KiB) Viewed 11639 times
Last edited by kaxyus on 23 Mar 2012, 19:02, edited 1 time in total.

kaxyus
Posts: 8
Joined: 22 Mar 2012, 12:05

Re: Wrong Geometry

#5 Post by kaxyus »

32 heads
Analyze(32).png
Analyze(32).png (35.57 KiB) Viewed 11639 times
32 heads
QuickSearch(32).png
QuickSearch(32).png (38.49 KiB) Viewed 11639 times
thanks for your help

User avatar
Fiona
Posts: 2835
Joined: 18 Feb 2012, 17:19
Location: Ludwigsburg/Stuttgart - Germany

Re: Wrong Geometry

#6 Post by Fiona »

If I ask the list of files TestDisk detects only two folders that contain a few gigabytes.
I assume that folders are lacking?
As far as I've seen, you've got a couple of read errors.
http://forum.cgsecurity.org/phpBB3/down ... php?id=189
http://forum.cgsecurity.org/phpBB3/down ... php?id=190
It could indicate a damaged file system.
You should stress your harddisk as little as possible.

Need an explanation about this;
Inserting the correct parameters TestDisk assigns a different dimension of the disc (8455 MB), much lower than the correct one.
3.5 inches harddisks using most 255 heads.

Something to do first might be to have a try to access more data and copy it using a boot sector diagnose.
Start TestDisk.
Confirm through until you see the menu Analyse.
Don't confirm at Analyse but Advanced.
Confirm at Boot with enter.
Highlight Rebuild BS and hit Enter.
Rebuild BS will be in progress.
Normally, it takes some minutes.
If it's finished, please post the infos or upload a screen.
If you see a menu List, please highlight it and press enter.
Please let me know, do you see your data or an error message.
To get back to the previous screen, easily press q for Quit.

If Rebuild BS hangs or last ages, please stop it.
It indicates a damaged file system.
I have no desire to stress your disk more than necessary.

Infos will follow.

kaxyus
Posts: 8
Joined: 22 Mar 2012, 12:05

Re: Wrong Geometry

#7 Post by kaxyus »

Hello Fiona,
exactly, the hard disk was full of data: about 950gb.
Originally there was, at the first level, a single folder and then at the second level, five other subfolders. At the second level, now, are visible only two folders that contain a small amount of data.
I will do the checks that you suggested and will post the data.
Thanks again.

User avatar
Fiona
Posts: 2835
Joined: 18 Feb 2012, 17:19
Location: Ludwigsburg/Stuttgart - Germany

Re: Wrong Geometry

#8 Post by Fiona »

Please let me know the result, that TestDisk checks your file system during rebuild of your boot sector.
In some cases it worked!

kaxyus
Posts: 8
Joined: 22 Mar 2012, 12:05

Re: Wrong Geometry

#9 Post by kaxyus »

Hello Fiona,
here the screenshots related to the Boot and Rebuild BS command.
Rebuild BS was very quick, few seconds. The List menu appeared, but the result has not changed: the root folder appears, but inside there are only two folders, not all of those originally present.
Boot.jpg
Boot.jpg (35.98 KiB) Viewed 11619 times
RebuildBS.jpg
RebuildBS.jpg (36.06 KiB) Viewed 11619 times

User avatar
Fiona
Posts: 2835
Joined: 18 Feb 2012, 17:19
Location: Ludwigsburg/Stuttgart - Germany

Re: Wrong Geometry

#10 Post by Fiona »

There is no change.
Looks like your file system is damaged.
In your case datarecovery software mit be necessary.
You can use PhotRec or commercial software if you want to try it first (demo).
PhotoRec doesn't keep file names and directories.

Fiona

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