TestDisk 6.2-WIP, Data Recovery Utility, November 2005
Christophe GRENIER <grenier@cgsecurity.org>
http://www.cgsecurity.org
Disk /dev/sda - 120 GB / 111 GiB - CHS 14593 255 63
Current partition structure:
Partition Start End Size in sectors
1 * FAT32 0 1 1 1010 254 63 16241652 [NO NAME]
2 P Linux 1011 0 1 1023 254 63 208845 [/boot]
3 E extended LBA 1024 0 1 14592 254 63 217985985
5 L Linux RAID 1024 1 1 3573 254 63 40965687 [md0]
X extended 3574 0 1 4210 254 63 10233405
6 L Linux RAID 3574 1 1 4210 254 63 10233342 [md1]
X extended 4211 0 1 14592 254 63 166786830
7 L Linux 4211 1 1 14592 254 63 166786767
*=Primary bootable P=Primary L=Logical E=Extended D=Deleted
[Proceed ] [ Save ]
Try to locate partition
Analyzes a drive's current partition structure and seeks partitions, making it possible to recover lost partitions.
TestDisk's Analyse does a quick check of the partition structure. TestDisk can handle several type of partitions:
Intel partition structure is composed of the MBR table and extended partitions. The MBR is limited to four entries. One of the entries can be an extended partition allowing several logical partitions. Each logical partition is contained by an extended partition/container. The MBR and each extended partition must end with the two bytes 0x55 and 0xAA, in that order; which make up the Hex Word 0xAA55 (since x86 CPU systems are 'little-endian'). A partition entry is composed of:
Only one primary partition can have the boot flag set. CHS information storage is limited to a maximum of 1024 cylinders (0-1023), that's why we have the famous 8 GB limitation (1024*255*63 = 16450560 sectors = 8422686720 bytes).
Modern operating systems and BIOS chips use LBA mode to access the data, but FAT12/16/32 boot sectors still make reference to CHS geometry. TestDisk checks that each value is in the authorized range: i.e., no sector value less than 1 nor higher than the number of sectors per head. The partition entries are read using logical start and size in sectors, then TestDisk checks if the logical values match the CHS values. TestDisk also checks that no partition data shows a partition as ending after the end of the disk, and that none of them are overlapping each other.
Sun label can have up to 8 partition entries. Entrie number 2 is reserved for the whole disk.
Following the filesystem type, TestDisk runs some basic checks on the boot sector/superblock of each filesystem. As ext2/ext3/reiserfs/jfs share the same filesystem type: 0x83, TestDisk has to check for each filesystem. The checks are the same as those used when TestDisk is searching for partitions:
This phase is very quick as the checks are minimal.
In a second step, TestDisk searches for 'lost partitions' without making use of any results from the previous step. This is the heart of TestDisk's powerful capabilities! TestDisk assumes the existence of partitions and scans all relevant drive cylinders for them. A primary partition starts at the beginning of a cylinder (head=0, sector=1), while a logical partition starts a little further along (head=1, sector=1). For each possible partition starting location, TestDisk can search for the presence of a filesystem header (FAT or NTFS boot sector, EXT2/EXT3 superblock, BSD disklabel...), which confirms the presence of a known partition type. Thus, the size of a partition is determined directly from its structure on the disk. Each partition that TestDisk discovers is added to a list of found partitions.
To detect a FAT32 partition, TestDisk searchs for a 0xAA55 endmark and the signature "FAT32", it also runs the corresponding FAT filesystem checks:
where "0xXX" could be any byte, and...
0xeb: A Short Jump, displacement relative to next instruction (only 8 bit).
0x90: NOP (do nothing).
0xe9: A Near Jump, displacement relative to next instruction (32 or 16 bit).
Some specific checks for FAT32 are done:
To detect an NTFS partition, TestDisk searchs for an 0xAA55 endmark and the signature "NTFS", it also checks that some FAT specific values are all set to zero (0): The number of reserved sectors, number of FATs, number of directory entries, 16-bit size of filesystem, 32-bit size of filesystem, Sectors per FAT. The number of Sectors per Cluster must be greater than zero.
For FAT and NTFS filesystem, the size of the partition will be read in the bootsector itself.
TestDisk 6.2-WIP, Data Recovery Utility, November 2005 Christophe GRENIER <grenier@cgsecurity.org> http://www.cgsecurity.org Disk /dev/sda - 120 GB / 111 GiB - CHS 14593 255 63 Analyse cylinder 1011/14592: 00% FAT32 0 1 1 1010 254 63 16241652 [NO NAME] Stop
Once the analysis is complete, TestDisk generates a report of found partitions.
TestDisk 6.2-WIP, Data Recovery Utility, November 2005
Christophe GRENIER <grenier@cgsecurity.org>
http://www.cgsecurity.org
Disk /dev/sda - 120 GB / 111 GiB - CHS 14593 255 63
Partition Start End Size in sectors
* FAT32 0 1 1 1010 254 63 16241652 [NO NAME]
P Linux 1011 0 1 1023 254 63 208845 [/boot]
D Linux 1024 1 1 3573 254 63 40965687
D Linux RAID 1024 1 1 3573 254 63 40965687 [md0]
D Linux 3574 1 1 4210 254 63 10233342
D Linux RAID 3574 1 1 4210 254 63 10233342 [md1]
L Linux 4211 1 1 14592 254 63 166786767
Structure: Ok. Use Up/Down Arrow keys to select partition.
Use LEFT/RIGHT Arrow keys to CHANGE partition characteristics:
*=Primary bootable P=Primary L=Logical E=Extended D=Deleted
Keys A: add partition, L: load backup, T: change type, P: list files,
ENTER: to continue
FAT32, 8315 MB / 7930 MiB
You can list files of NTFS, FAT, EXT2/EXT3 and ReiserFS partition by pressing P (FAT directory listing is limited to 5 clusters, some files may not appears).
TestDisk 6.2-WIP, Data Recovery Utility, November 2005 Christophe GRENIER <grenier@cgsecurity.org> http://www.cgsecurity.org * FAT32 0 1 1 1010 254 63 16241652 [NO NAME] Use right arrow to change directory, q to quit Directory / -rwxr-xr-x 0 0 805306368 20-Jul-2005 10:35 PAGEFILE.SYS drwxr-xr-x 0 0 0 14-Feb-2005 22:41 WINDOWS -r-xr-xr-x 0 0 4952 28-Aug-2001 15:00 Bootfont.bin -r-xr-xr-x 0 0 251712 3-Aug-2004 22:59 NTLDR -r-xr-xr-x 0 0 47564 3-Aug-2004 22:38 NTDETECT.COM -rwxr-xr-x 0 0 212 14-Feb-2005 22:51 BOOT.INI drwxr-xr-x 0 0 0 14-Feb-2005 22:47 Documents and Settings dr-xr-xr-x 0 0 0 14-Feb-2005 22:55 Program Files -rwxr-xr-x 0 0 0 14-Feb-2005 22:56 CONFIG.SYS -rwxr-xr-x 0 0 0 14-Feb-2005 22:56 AUTOEXEC.BAT -r-xr-xr-x 0 0 0 14-Feb-2005 22:56 IO.SYS -r-xr-xr-x 0 0 0 14-Feb-2005 22:56 MSDOS.SYS drwxr-xr-x 0 0 0 14-Feb-2005 23:02 System Volume Information -rwxr-xr-x 0 0 536399872 20-Jul-2005 10:36 HIBERFIL.SYS
Using the list of found partitions, you can edit the partition table.
There are three kinds of edits:
As you make edits, watch the status of the partition table's structure. It will be either "Ok" or "Bad".
Structure: Ok should appear if everything is ok, i.e., no primary partition between two extended partitions, only one or no bootable partitions, no partitions using the same disk space.
When you are satisfied with the edited partition table, press Enter. If you've made any edits, TestDisk gives you a choice of writing that data to the drive's Partition Table, or of running a more detailed analysis.
Quit
Quits (exits) from the TestDisk program without making any changes (unless you pressed the ENTER key while Write was 'highlighted').
Search!
The quick first scan may have miss some partitions. Search! will also search for FAT32 backup boot sector, NTFS backup boot superblock, EXT2/EXT3 backup superblock to detect more partitions, it will scan each cylinder.
Write
Writes the changes that have been made in TestDisk's memory buffer to the hard drive. If you are unsure of the changes (often to the MBR's Partition Table), then don't use this function!
Extd Part
If there is logical partition, this flag lets you decide if the extended partition will used all avaible disk space or only the required (minimal) space.
TestDisk 6.2-WIP, Data Recovery Utility, November 2005
Christophe GRENIER <grenier@cgsecurity.org>
http://www.cgsecurity.org
Disk /dev/sda - 120 GB / 111 GiB - CHS 14593 255 63
Partition Start End Size in sectors
1 * FAT32 0 1 1 1010 254 63 16241652 [NO NAME]
2 P Linux 1011 0 1 1023 254 63 208845 [/boot]
3 E extended LBA 1024 0 1 14592 254 63 217985985
5 L Linux RAID 1024 1 1 3573 254 63 40965687 [md0]
6 L Linux RAID 3574 1 1 4210 254 63 10233342 [md1]
7 L Linux 4211 1 1 14592 254 63 166786767
[ Quit ] [Search! ] [ Write ]
Return to main menu
Here TestDisk asks you to confirm the Write operation; so you have the final choice over what TestDisk will actually do.
TestDisk 6.2-WIP, Data Recovery Utility, November 2005 Christophe GRENIER <grenier@cgsecurity.org> http://www.cgsecurity.org Write partition table, confirm ? (Y/N)
Back to Running the TestDisk Program