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User Guide: How to recover NTFS Step by step guide with examples
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- NTFS Partition Recovery Concepts
- NTFS File Recovery Concepts
1. NTFS Partition Recovery Concepts
For the machine to be able to start booting properly, the following conditions should apply:
- Master Boot Record (MBR) exists and is safe
- Partition Table exists and contains at least one active partition
If so, executable code in MBR selects an active partition and passes control there, thus it can start loading proper files (COMMAND.COM, NTLDR, . ) depending on the file system type on that partition. However, if these files are missing or corrupted then OS will be unbootable - remember the famous error 'NTLDR is missing .' ?
In this case recovery software accesses this drive on the low level bypassing system boot (for example, if you boot from another HDD or bootable floppy) and will help you to see all other files and directories on the drive and allow you to copy to the safe place onto another drive.
For the partition/drive to be visible to the Operating System the following conditions should apply:
- Partition/Drive can be found via Partition Table
- Partition/Drive boot sector is safe
If so, OS can read partition/drive parameters and display drive in the list of the available drives.
However, if the file system itself is damaged (Root, FAT area on FAT12/FAT16/FAT32, or system MFT records on NTFS) drive's content might not be displayed and we might see errors like 'MFT is corrupted', 'Drive is invalid' .
In this case you have less chances to restore your data in compare to the case where OS is not bootable due to the missing or corrupted system files, however recovery software usually uses some tricks to display may be not all but some of the entries that are still safe and allow you to save your data to another location.
Under 'Partition recovery' we mean two things:
Physical partition recovery. The goal is to find out the problem and write some information to the proper place on HDD and after that partition becomes visible to OS again. You can do it manually using Disk Editors and some guidelines or use recovery software, designed for this purpose.
Virtual partition recovery. The goal is to determine the critical parameters of the deleted/damaged/overwritten partition and after that enable to scan it and display its content. This approach can be applied in some cases when physical partition recovery is not possible (for example, partition boot sector is dead) and is commonly used by recovery software. It's very hard (almost impossible) to implement it manually.Lets consider the topics, related to the recovery of partitions in common, not specific to the particular file system. We have the following cases:
- MBR is damaged
- Partition is deleted or Partition Table is damaged
- Partition Boot Sector is damaged
- Missing or Corrupted System Files
As an example we'll use the following disk layout:
MBR is damaged
The Master Boot Record (MBR) will be created when you create the first partition on the hard disk. It is very important data structure on the disk.
The Master Boot Record contains the Partition Table for the disk and a small amount of executable code for the boot start. The location is always the first sector on the disk.
The first 446 (0x1BE) bytes are MBR itself, the next 64 bytes are the Partition Table, the last two bytes in the sector are a signature word for the sector and are always 0x55AA. For our disk layout we have MBR:
What will happen if the first sector has been damaged (by virus, for example)?
Lets overwrite the first 16 bytes with zeros.
When we try to boot after hardware testing procedures, we see just blank screen without any messages. It means the piece of code at the beginning of the MBR could not be executed properly.
That's why even error messages could not be displayed. However, if we boot from the floppy, we can see FAT partition, files on it and we are able to perform standard operations like file copy, program execution.
It happens because in our example only part of the MBR has been damaged which does not allow the system to boot properly. However, the partition table is safe and we can access our drives when we boot from the operating system installed on the other drive.
What will happen if sector signature (last word 0x55AA) has been removed or damaged?
Lets write zeros to the location of sector signature.
When we try to boot now, we see an error message like 'Operating System not found'. Thus the first thing if computer does not boot is to run Disk Viewer and check the first physical sector onHDD, whether it looks like valid MBR or not:
- check, may be it's filled up with zeros or any other single character
- check whether error messages (like you can see above 'Invalid partition table'.) are present or not
- check whether disk signature (0x55AA) is present or not
The simplest way to repair or re-create MBR is to run Microsoft's standard utility called FDISK with a parameter /MBR, like
FDISK is a standard utility included in MS-DOS, Windows 95, 98, ME. If you have Windows NT / 2000 / XP, you can boot from startup floppy disks or CD-ROM, choose repair option during setup, and run Recovery Console. When you are logged on, you can run FIXMBR command to fix MBR.
Also you can use third party MBR recovery software or if you've created MBR backup, restore it from there (Active@ Partition Recovery has such capabilities).
What will happen if the first sector is bad or unreadable?
Most likely we'll get the same black screen, which we got when trying to boot.
When you try to read it using Disk Viewer/Editor you should get an error message saying that sector is unreadable. In this case recovery software is unable to help you to bring HDD back to the working condition, i.e. physical partition recovery is not possible. The only thing that can be done is to scan and search for partitions (i.e. perform virtual partition recovery), and in case if something is found - display them and give the user an opportunity to save important data to another location. Third party software, like Active@ File Recovery, will help you here.
Partition is deleted or Partition Table is damaged
The information about primary partitions and extended partition is contained in the Partition Table, a 64-byte data structure, located in the same sector as the Master Boot Record (cylinder 0, head 0, sector 1).
The Partition Table conforms to a standard layout, which is independent of the operating system. The last two bytes in the sector are a signature word for the sector and are always 0x55AA.
For our disk layout we have Partition Table:
We can see three existing and one empty entries:
- Partition 1, offset 0x01BE (446)
- Partition 2, offset 0x01CE (462)
- Partition 3, offset 0x01DE (478)
- Partition 4 - empty, offset 0x01EE (494)
Each Partition Table entry is 16 bytes long, making a maximum of four entries available. Each partition entry has fields for Boot Indicator (BYTE), Starting Head (BYTE), Starting Sector (6 bits), Starting Cylinder (10 bits), System ID (BYTE), Ending Head (BYTE), Ending Sector (6 bits), Ending Cylinder (10 bits), Relative Sector (DWORD), Total Sectors (DWORD).
Thus the MBR loader can assume the location and size of partitions. MBR loader looks for the 'active' partition, i.e. partition that has Boot Indicator equals 0x80 (the first one in our case) and passes control to the partition boot sector for further loading.
Lets consider the situations which cause computer to hang up while booting or data loss.
What will happen if no partition has been set to the Active state (Boot Indicator=0x80)? Paypal scratch cards.
Lets remove Boot Indicator from the first partition:
When we try to boot now, we see an error message like 'Operating System not found'. It means that the loader cannot determine which partition is system and active to pass control to.
What will happen if partition has been set to the Active state (Boot Indicator=0x80) but there are no system files on that partition(it could happen if we had used for example FDISK and selected not the proper active partition)?
Loader will try to boot from there, fails, try to boot again from other devices like floppy, and if fails to boot again, we'll see an error message like 'Non-System Disk or Disk Error'. Colibri 1 8 9 – native lossless macos audio players.
What will happen if partition entry has been deleted?
If it has been deleted, next two partitions will move one line up in the partition table.
If we try to boot now, the previous second (FAT) partition becomes the first and the loader will try to boot from it. And if it's not a system partition, we'll get the same error messages.
What will happen if partition entry has been damaged?
Let's write zeros to the location of the first partition entry.
If we try to boot now, the MBR loader will try to read and interpret zeros (or other garbage) as partition parameters and we'll get an error message like 'Missing Operating System'. Metamovie 2 2 4 – add metadata to your videos.
Thus, the second step in partition recovery is to run Disk Viewer and to make sure that the proper partition exists in the partition table and has been set as active.
How can recovery software help you in the above-mentioned scenarios?
- Discover and suggest you to choose the partition to be active (even FDISK does so).
- Discover and suggest you to choose the partition to be active.
- Perform a free disk space scan to look for partition boot sector or remaining of the deleted partition information in order to try to reconstruct Partition Table entry for the deleted partition.
- Perform all disk space scan to look for partition boot sector or remaining of the damaged partition information in order to try to reconstruct Partition Table entry for the damaged partition entry.
Why partition boot sector is so important?
Because if recovery software finds it, all necessary parameters to reconstruct partition entry in the Partition Table are there. (see Partition Boot Sector topic for details).
What would happen if partition entry had been deleted then recreated with other parameters and re-formatted?
In this case, instead of the original partition entry we would have a new one and everything would work fine except that later on we could recall that we had some important data on the original partition.
If you've created MBR, Partition Table, Volume Sectors backup (for example, Active@ Partition Recovery and Active@ UNERASER (Unformat) can do it) before, you can virtually restore it back and look for your data (in case if it has not been overwritten with new data yet).
Ishowu instant 1 2 7. Some advanced recovery tools also have an ability to scan disk surface and try to reconstruct the previously deleted partition information from the pieces of left information (i.e. perform virtual partition recovery). However it is not guaranteed that you can recover something.
Partition Boot Sector is damaged
The Partition Boot Sector contains information, which the file system uses to access the volume. On personal computers, the Master Boot Record uses the Partition Boot Sector on the system partition to load the operating system kernel files. Partition Boot Sector is the first sector of the Partition.
For our first NTFS partition we have boot sector:
The printout is formatted in three sections:
Bytes 0x00– 0x0A are the jump instruction and the OEM ID (shown in bold print).
Bytes 0x0B–0x53 are the BIOS Parameter Block (BPB) and the extended BPB. This block contains such essential parameters as Bytes Per Sector (WORD, offset 0x0B), Sectors Per Cluster (BYTE, offset 0x0D), Media Descriptor (BYTE, offset 0x15), Sectors Per Track (WORD, offset 0x18), Number of Heads (WORD, offset 0x1A), Hidden Sectors (DWORD, offset 0x1C), Total Sectors (LONGLONG, offset 0x28), etc.
The remaining code is the bootstrap code (that is necessary for the proper system boot) and the end of sector marker (shown in bold print).
This sector is so important on NTFS, for example, duplicate of the boot sector is located on the disk.
Boot Sector for FAT looks different, however its BPB contains parameters similar to the above mentioned. There is no extra copy of this sector stored anywhere, so recovery on FAT is as half as less successful than on NTFS.
What will happen if Partition Boot Sector is damaged or bad/unreadable?
Let's fill up with zeros several lines of Partition Boot Sector:
If we try to boot, we'll see 'Non System Disk' or 'Disk Error.'. After we fail to load from it and from floppy, partition becomes unbootable.
Because a normally functioning system relies on the boot sector to access a volume, it is highly recommended that you run disk-scanning tools such as CHKDSK regularly, as well as back up all of your data files to protect against data loss in case you lose access to the volume.
Tools like Active@ Partition Recovery and Active@ UNERASER allow you to create backup of MBR, Partition Table and Volume Boot Sectors so that if for some reason it fails to boot, you can always restore your partition information and have an access to files/folders on that partition.
What to do if this sector is damaged?
If we do have backup of the whole disk or MBR/Boot Sectors we can try to restore it from there.
If we do not have backup, in case of NTFS we could try to locate a duplicate of Partition Boot Sector and get information from there.
If duplicate boot sector is not found, only virtual partition recovery might be possible if we can determine critical partition parameters such as Sectors per Cluster, etc.
How can we fix NTFS boot sector using standard Windows NT/2000/XP tools?
On NTFS copy of boot sector is stored at the middle or at the end of the Volume. You can boot from startup floppy disks or CD-ROM, choose repair option during setup, and run Recovery Console. When you are logged on, you can run FIXBOOT command to try to fix boot sector.
How can recovery software help you in this situation?
It can backup MBR, Partition Table and Boot Sectors and restore them in case of damage
It can try to find out duplicate boot sector on the drive and re-create the original one or perform virtual data recovery based on found partition parameters
Some advanced techniques allow assuming drive parameters even if duplicate boot sector is not found (i.e. perform virtual partition recovery) and give the user virtual access to the data on the drive to be able to copy them to the safer location.
Missing or Corrupted System Files
For Operating System to boot properly, system files required to be safe. In case of Windows NT / 2000 / XP these files are: NTLDR, ntdetect.com, boot.ini, located at the root folder of the bootable volume, Registry files (i.e., SAM, SECURITY, SYSTEM and SOFTWARE), etc.
Windows Vist and newer Windows versions have completely different set of boot system files. These files are BOOTMGR (Windows Boot Manager), BCD (Boot Configuration Data), winload.exe.
If these files have been deleted, corrupted, damaged by virus, Windows will be unable to boot. You'll see an error message 'NTLDR is missing' or 'BOOTMGR is missing'. So, the next step in recovery process is to check the existence and safety of system files (for sure, you won't able to check them all, but you must check at least NTLDR,ntdetect.com, boot.ini which cause most of problems).
To do it in Windows NT / 2000 / XP, you can use Emergency Repair Process, Recovery Console or third party recovery software.
Emergency Repair Process
To proceed with Emergency Repair Process, you need Emergency Repair Disk (ERD). This disk is recommended to create after you install and customize Windows. To create it, use the 'Backup' utility from System Tools. You can use the ERD to repair damaged boot sector, damaged MBR, repair or replace missing or damaged NT Loader (NTLDR) and ntdetect.com files.
If you do not have an ERD, the emergency repair process can attempt to locate your Windows installation and start repairing your system, but it may not be able to do so. To run the process, boot from Windows bootable disks or CD, and choose Repair option when system suggests you to proceed with installation or repairing.
Then press R to run Emergency Repair Process and choose Fast or Manual Repair option. Fast Repair is recommended for most users, Manual Repair — for Administrators and advanced users only.
If the emergency repair process is successful, your computer will automatically restart and you should have a working system
Recovery Console
Recovery Console is a command line utility similar to MS-DOS command line. You can list and display folder content, copy, delete, replace files, format drives and perform many other administrative tasks.
To run Recovery Console, boot from Windows bootable disks or CD and choose Repair option, when system suggests you to proceed with installation or repairing and then press C to run Recovery Console.
You will be asked to which system you want to log on to and then for Administrator's password, and after you logged on — you can display drive's contents, check the existence and safety of critical files and, for example, copy them back if they have been accidentally deleted.
Recovery Software
Third party recovery software in most cases does not allow you to deal with system files due to the risk of further damage to the system, however you can use it to check for the existence and safety of these files.
NTFS File Recovery Concepts
File recovery process can be briefly described as drive or folder scanning to find deleted entries in Master File Table (MFT) then for the particular deleted entry, defining clusters chain to be recovered and then copying contents of these clusters to the newly created file.
Different file systems maintain their own specific logical data structures, however basically each file system:
- Has a list or catalog of file entries, so we can iterate through this list and entries, marked as deleted
- Keeps for each entry a list of data clusters, so we can try to find out set of clusters composing the file
After finding out the proper file entry and assembling set of clusters, composing the file, read and copy these clusters to another location.
Step by Step with examples:
- Scan Disk for deleted entries
- Defining clusters chain for the deleted entry
- Clusters chain recovery
However, not every deleted file can be recovered, there are some assumptions, for sure:
First, we assume that the file entry still exists (not overwritten with other data). The less the files have been created on the drive where the deleted file was resided, the more chances that space for the deleted file entry has not been used for other entries.
Second, we assume that the file entry is more or less safe to point to the proper place where file clusters are located. In some cases (it has been noticed in Windows XP, on large FAT32 volumes) operating system damages file entries right after deletion so that the first data cluster becomes invalid and further entry restoration is not possible.
Third, we assume that the file data clusters are safe (not overwritten with other data). The less the write operations have been performed on the drive where deleted file was resided, the more chances that the space occupied by data clusters of the deleted file has not been used for other data storage.
As general advices after data loss:
DO NOT WRITE ANYTHING ONTO THE DRIVE CONTAINING YOUR IMPORTANT DATA THAT YOU HAVE JUST DELETED ACCIDENTALLY! Even file recovery software installation could spoil your sensitive data. If the data is really important to you and you do not have another logical drive to install software to, take the whole hard drive out of the computer and plug it into another computer where data recovery software has been already installed or use recovery software that does not require installation, for example recovery software which is capable to run from bootable floppy.
DO NOT TRY TO SAVE ONTO THE SAME DRIVE DATA THAT YOU FOUND AND TRYING TO RECOVER! When saving recovered data onto the same drive where sensitive data is located, you can intrude in process of recovering by overwriting FAT/MFT records for this and other deleted entries. It's better to save data onto another logical, removable, network or floppy drive.
Disk Scan for deleted entries
Disk Scan is a process of low-level enumeration of all entries in Master File Table (MFT) on NTFS, NTFS5. The goal is to find and display deleted entries.
In spite of different file/folder entry structure for the different file systems, all of them contain basic file attributes like name, size, creation and modification date/time, file attributes, existing/deleted status, etc.
Given that a drive contains root file table and any file table (MFT, root folder of the drive, regular folder, or even deleted folder) has location, size and predefined structure, we can scan it from the beginning to the end checking each entry, if it's deleted or not and then display information for all found deleted entries.
Deleted entries are marked differently depending on the file system. On NTFS deleted entry has a special attribute in file header that points whether the file has been deleted or not.
Example of scanning folder on NTFS5:
For our drive we have input parameters:
- Total Sectors 610406
- Cluster size 512 bytes
- One Sector per Cluster
- MFT starts from offset 0x4000, non-fragmented
- MFT record size 1024 bytes
- MFT Size 1968 records
Thus we can iterate through all 1968 MFT records, starting from the absolute offset 0x4000 on the volume looking for the deleted entries. We are interested in MFT entry 57 having offset 0x4000 + 57 * 1024 = 74752 = 0x12400 because it contains our recently deleted file 'My Presentation.ppt'
Below MFT record number 57 is displayed:
MFT Record has pre-defined structure. It has a set of attributes defining any file of folder parameters.
MFT Record begins with standard File Record Header (first bold section, offset 0x00):
- 'FILE' identifier (4 bytes)
- Offset to update sequence (2 bytes)
- Size of update sequence (2 bytes)
- $LogFile Sequence Number (LSN) (8 bytes)
- Sequence Number (2 bytes)
- Reference Count (2 bytes)
- Offset to Update Sequence Array (2 bytes)
- Flags (2 bytes)
- Real size of the FILE record (4 bytes)
- Allocated size of the FILE record (4 bytes)
- File reference to the base FILE record (8 bytes)
- Next Attribute Id (2 bytes)
The most important information for us in this block is a file state: deleted or in-use. If Flags(in red color) field has bit 1 set, it means that file is in-use. In our example it is zero, i.e. file is deleted.
Starting from 0x48, we have Standard Information Attribute (second bold section):
- File Creation Time (8 bytes)
- File Last Modification Time (8 bytes)
- File Last Modification Time for File Record (8 bytes)
- File Access Time for File Record (8 bytes)
- DOS File Permissions (4 bytes) 0x20 in our case Archive Attribute
Following standard attribute header, we have File Name Attribute belonging to DOS name space, short file names, (third bold section, offset 0xA8) and again following standard attribute header, we have File Name Attribute belonging to Win32 name space, long file names, (third bold section, offset 0x120):
- File Reference to the Parent Directory (8 bytes)
- File Modification Times (32 bytes)
- Allocated Size of the File (8 bytes)
- Real Size of the File (8 bytes)
- Flags (8 bytes)
- Length of File Name(1 byte)
- File Name Space (1 byte)
- File Name (Length of File Name * 2 bytes)
In our case from this section we can extract file name, 'My Presentation.ppt', File Creation and Modification times, and Parent Directory Record number.
Starting from offset 0x188, there is a non-resident Data attribute (green section).
- Attribute Type (4 bytes) (e.g. 0x80)
- Length including header (4 bytes)
- Non-resident flag (1 byte)
- Name length (1 byte)
- Offset to the Name (2 bytes)
- Flags (2 bytes)
- Attribute Id (2 bytes)
- Starting VCN (8 bytes)
- Last VCN (8 bytes)
- Offset to the Data Runs (2 bytes)
- Compression Unit Size (2 bytes)
- Padding (4 bytes)
- Allocated size of the attribute (8 bytes)
- Real size of the attribute (8 bytes)
- Initialized data size of the stream (8 bytes)
- Data Runs .
Below MFT record number 57 is displayed:
MFT Record has pre-defined structure. It has a set of attributes defining any file of folder parameters.
MFT Record begins with standard File Record Header (first bold section, offset 0x00):
- 'FILE' identifier (4 bytes)
- Offset to update sequence (2 bytes)
- Size of update sequence (2 bytes)
- $LogFile Sequence Number (LSN) (8 bytes)
- Sequence Number (2 bytes)
- Reference Count (2 bytes)
- Offset to Update Sequence Array (2 bytes)
- Flags (2 bytes)
- Real size of the FILE record (4 bytes)
- Allocated size of the FILE record (4 bytes)
- File reference to the base FILE record (8 bytes)
- Next Attribute Id (2 bytes)
The most important information for us in this block is a file state: deleted or in-use. If Flags(in red color) field has bit 1 set, it means that file is in-use. In our example it is zero, i.e. file is deleted.
Starting from 0x48, we have Standard Information Attribute (second bold section):
- File Creation Time (8 bytes)
- File Last Modification Time (8 bytes)
- File Last Modification Time for File Record (8 bytes)
- File Access Time for File Record (8 bytes)
- DOS File Permissions (4 bytes) 0x20 in our case Archive Attribute
Following standard attribute header, we have File Name Attribute belonging to DOS name space, short file names, (third bold section, offset 0xA8) and again following standard attribute header, we have File Name Attribute belonging to Win32 name space, long file names, (third bold section, offset 0x120):
- File Reference to the Parent Directory (8 bytes)
- File Modification Times (32 bytes)
- Allocated Size of the File (8 bytes)
- Real Size of the File (8 bytes)
- Flags (8 bytes)
- Length of File Name(1 byte)
- File Name Space (1 byte)
- File Name (Length of File Name * 2 bytes)
In our case from this section we can extract file name, 'My Presentation.ppt', File Creation and Modification times, and Parent Directory Record number.
Starting from offset 0x188, there is a non-resident Data attribute (green section).
- Attribute Type (4 bytes) (e.g. 0x80)
- Length including header (4 bytes)
- Non-resident flag (1 byte)
- Name length (1 byte)
- Offset to the Name (2 bytes)
- Flags (2 bytes)
- Attribute Id (2 bytes)
- Starting VCN (8 bytes)
- Last VCN (8 bytes)
- Offset to the Data Runs (2 bytes)
- Compression Unit Size (2 bytes)
- Padding (4 bytes)
- Allocated size of the attribute (8 bytes)
- Real size of the attribute (8 bytes)
- Initialized data size of the stream (8 bytes)
- Data Runs .
In this section we are interested in Compression Unit size (zero in our case means noncompressed), Allocated and Real size of attribute that is equal to our file size (0xDC00 = 56320 bytes), and Data Runs (see the next chapter).
Defining clusters chain for the deleted entry
To define clusters chain we need to scan drive, going through one by one all file (NTFS) clusters belonging (presumably) to the file until we reach the file size equals to the total size of the selected clusters. If the file is fragmented, clusters chain will be composed of several extents in case of NTFS.
Location of these clusters can vary depending on file system. On NTFS each file has DATA attribute that describes 'data runs'. Disassembling data runs to 'extents' for each extent we have start cluster offset and number of clusters in extent, so enumerating extents, we can compose file's cluster chain.
You can try to define clusters chain manually, using low-level disk editors, like Active@ Disk Editor, however it's much simpler to use freeware data recovery tools, like Active@ UNERASER.
Example of defining clusters chain on NTFS
When recovering on NTFS part of DATA attribute called Data Runs give us location about file clusters. In most cases DATA attribute is stored inside MFT record, so if we found MFT record for the deleted file, most likely we'll be able to determine cluster's chain.
In example below DATA attribute is marked with a green color. Data Runs inside, marked as Bold.
Data Runs need to be decrypted. First byte (0x31) shows how many bytes are allocated for the length of the run (0x1 in our case) and for the first cluster offset (0x3 in our case). Next, we take one byte (0x6E) that points to the length of the run. Next, we pick up 3 bytes pointing to the start cluster offset (0xEBC404). Changing bytes order we get first cluster of the file 312555 (equals 0x04C4EB). Starting from this cluster we need to pick up 110 clusters (equals 0x6E).
Next byte (0x00) tells us that no more data runs exist. Our file is not fragmented, so we have the only one data run.
Lets check, isn't there enough information about the file data?
Cluster size is 512 bytes.We have 110 clusters, 110*512 = 56320 bytes
Our file size was defined as 56320 bytes, so we have enough information now to recover the file clusters.
Clusters chain recovery for the deleted entry
After clusters chain is defined, automatically or manually, the only task left is to read and save contents of the defined clusters to another place verifying their contents.
We have a chain of clusters; we can calculate each cluster offset from the beginning of the drive, using standard formulas. After that we copy amount of data equals to the cluster size, starting from the calculated offset into the newly created file. For the last one we copy not all cluster, but reminder from the file size minus number of copied clusters multiplied by cluster size.
Mac os x server. Formulas for calculating cluster offset could vary depending on file system.
To calculate, for example, offset of the cluster for FAT we need to know:
- Boot sector size
- Number of FAT supported copies
- Size of one copy of FAT
- Size of main root folder
- Number of sectors per cluster
- Number of bytes per sector
On the NTFS, we have linear space so we can calculate cluster offset simply as cluster number multiplied by cluster size.
Example of recovery clusters chain on NTFS
In our example we just need to pick up 110 clusters starting from the cluster 312555.
Cluster size is 512 byte, so the offset of the first cluster would be 512 * 312555 = 160028160 = 0x0989D600
Here is our data. What's left to do is just reading from this point 110 clusters (56320 bytes) and then copy them to another location. Data recovery is complete now.
Recommended software
Active@ File Recovery — software tool to recover deleted or otherwise lost files on NTFS
Recommended Reading
Glossary of Terms
compressed cluster
When you set a file or folder property to compress data, the file or folder uses less disk space. While the size of the file is smaller, it must use a whole cluster in order to exist on the hard drive. As a result, compressed clusters contain 'file slack space'. This space may contain residual confidential data from the file that previously occupied this space. KillDisk can wipe out the residual data without touching the existing data.
cluster
A logical group of disk sectors, managed by the operating system, for storing files. Each cluster is assigned a unique number when it is used. The operating system keeps track of clusters in the hard disk's root records or MFT records. (See lost cluster)
free cluster
A cluster that is not occupied by a file. This space may contain residual confidential data from the file that previously occupied this space. KillDisk can wipe out the residual data.
file slack space
The smallest file (and even an empty folder) takes up an entire cluster. A 10-byte file will take up 2,048 bytes if that is the cluster size. File slack space is the unused portion of a cluster. This space may contain residual confidential data from the file that previously occupied this space. KillDisk can wipe out the residual data without touching the existing data.
deleted boot records
All disks start with a boot sector. In a damaged disk, if the location of the boot records is known, the partition table can be reconstructed. The boot record contains a file system identifier.
ISO
An International Organization for Standardization ISO-9660 file system is a standard CD-ROM file system that allows you to read the same CD-ROM whether you're on a PC, Mac, or other major computer platform. Disk images of ISO-9660 file systems (ISO images) are a common way to electronically transfer the contents of CD-ROMs. They often have the filename extension .ISO (though not necessarily), and are commonly referred to as 'ISOs'.
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lost cluster
A cluster that has an assigned number in the file allocation table, even though it is not assigned to any file. You can free up disk space by reassigning lost clusters. In DOS and Windows, you can find lost clusters with the ScanDisk utility.
MFT records
Master File Table. A file that contains the records of every other file and directory in an NTFS-formatted hard disk drive. The operating system needs this information to access the files.
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root records
File Allocation Table. A file that contains the records of every other file and directory in a FAT-formatted hard disk drive. The operating system needs this information to access the files. There are FAT32, FAT16 and FAT versions.
sector
The smallest unit that can be accessed on a disk. Tracks are concentric circles around the disk and the sectors are segments within each circle.
unallocated space
Space on a hard disk where no partition exists. A partition may have been deleted or damaged or a partition may not have been created.
Windows system records
The Windows registry keeps track of almost everything that happens in windows. This enhances performance of the computer when doing repetitive tasks. Over time, these records can take up a lot of space.