NTFS

Microsoft NTFS is a proprietary file system developed by Microsoft for the operating system Microsoft Windows NT, including its successors 2000, XP, Server 2003, Vista, Server 2008, Windows 7, Server 2008 R2 and Windows 8 The acronym stands for New Technology File System.

Compared with the FAT file system NTFS offers, among other targeted access protection at the file level as well as greater data security through journaling. However, no such broad compatibility is given as FAT. Another advantage of NTFS is that the file size is not limited as in FAT to 4 GiB. Larger files are needed, for example when creating DVD images.

• 4.1 from NTFS 1.X
• 4.2 from NTFS 2.X
• 4.3 from NTFS 3.x 4.3.1 Analysis points

• 4.4.1 Transactional NTFS ( TxF )

• 6.1 Access with DOS -based operating systems
• 6.2 Access to Unix -based operating systems

History

As the development of NT, the later Microsoft Windows NT 3.1 started, it was not clear which file system would use the future operating system. At this time there were the FAT16 file system, which was used by MS- DOS and HPFS file system from OS / 2 Although both file systems were common, but in the opinion of David Cutler both did not meet the requirements of reliability, which he presented to the operating system. The new file system would be able, in his view, to restore damaged files automatically. In addition, both file systems have limitations on maximum file size and number, and it was expected that the new operating system would manage in the future, large amounts of data. The development of a third file system threatened, however, jeopardizing the schedule of the operating system.

Thus began the first phase of the new file system specification. The FAT16 file names were limited to the 8.3 format. These names were usually as cryptic and hard to remember. Although HPFS supported file names up to 255 characters long, but older DOS or Windows programs could not see these files. NTFS should solve this problem by having each long file name automatically received a short- form through which the file can be edited by older applications.

However, the development of the new file system stood on shaky legs. The April 1991 nearly the end for NTFS means when several developers opted to specifically to stop the development of this file system due to time constraints. Only when Cutler, who was at that time on vacation, came back and ordered the resumption of development, the work continued. In February 1992, the testing phase of the new file system began in October, the file system was stable enough for daily use.

Structure - MFT

NTFS inherited many of the concepts of the file system HPFS from IBM that was used in the initially developed together with Microsoft OS / 2.

From the perspective of the file system - it follows the NTFS file system concept of Unix - is all part of a file, the information of the system. The main file is the Master File Table, MFT shortly. In this file are the entries which blocks belong to which file access permissions and attributes. Among the properties ( attributes ) of a file under NTFS file size, date include file creation, last modification date, sharing, file type, and also the actual file content.

Very small files and directories are stored directly in the MFT. Larger files are then stored as an attribute in a data drive. There are 4 stages of the file growth.

Formatting the hard disk a fixed space is reserved for the MFT, which can not be occupied by other files. When this is full, the file system free space starts to use from disk, which can lead to fragmentation of the MFT. By default, a reserved area of 12.5 % of the partition size is accepted.

When storing metadata journal is launched, meaning that a planned action is first written to the journal. Then, the actual write access to the data is performed, and finally the journal is updated. If a write access is not completely finished, for example, because of a crash, the file system, only the changes in the journal needs to withdraw and is then returned to a consistent state.

NTFS versions

The following list reflects the association between NTFS and Windows version resist:

• NTFS 1.0 - Microsoft Windows NT 3.1
• NTFS 1.1 - Microsoft Windows NT 3.5/3.51
• NTFS 2 - Microsoft Windows NT 4.0
• NTFS 3.0 - Microsoft Windows NT 4.0 Service Pack 4 and Windows 2000 ( NT 5.0 )
• NTFS 3.1 - Microsoft Windows XP ( NT 5.1 )

Version Compatibility

• The only upward compatibility is for version 3.0 to 3.1 as the disc formats are identical. Thus, even NT 4.0 still using Windows XP partitions except the necessary Windows domain controller USN journal in a dual boot scenario on the same machine.
• Basically, all other versions are from NTFS to earlier versions backward compatible ( newer Windows versions have full access to older versions of NTFS ), but later versions are not forward compatible without updated drivers.

Differences compared with the FAT file system

From NTFS 1.X

The differences compared to FAT are:

• Efficient memory usage on partitions over 400 MiB
• Metadata journaling: The file system structures are always in a consistent state
• Long file names: File names can as opposed to FAT16 be up to 255 characters long natively (without VFAT) and consist of almost any Unicode character. NTFS is case- sensitive; this is not supported by Win32 applications, POSIX applications can, however, correctly manage files that differ only in case- insensitive.
• Maximum length of the full path name of 32,767 characters.
• Flexible management of privileges by using Access Control Lists
• Maximum file size of 16 theoretically Exbibyte ( EIB )
• Fast and efficient storage of small files directly in the MFT (from Windows NT 3.51 by default 4096 bytes used large clusters )
• Storing alternate data streams
• Transparent compression of files ( is, although developed from the beginning, only from version 3.51 and Windows NT implements only supported for unencrypted files and cluster sizes up to 4 KiB).
• Increased defragmentation speed.

From NTFS 2.X

• Data encryption ( only at the file level )

From NTFS 3.x

• Transparent file encryption with EFS (not in the Windows XP Home Edition and only uncompressed data )
• Quotas to limit the usable disk space for individual users,
• Analysis points (English reparse point) for the associations between actions / functions with files or directories,
• Hard Links: Each file can be referenced by up to 1023 file name (a file, a lot of names )
• Are for files with many empty content when they are marked as file sparse, only actually written sections stored.

Analysis points

Analysis points represent a flexible extension for the file system by linking it file system entries with features. These can be used in many different ways and expanded in future versions. A file system driver that does not know a particular type of analysis point, this does not execute. When accessing a reparse point, the function-specific analytical data are dynamically evaluated by the appropriate function (hence " analysis"). This implies that such an analysis can also fail with an access to the data provided by the analysis point (possibly by current, temporary circumstances ) is not possible.

The following functions are currently supported by NTFS:

• Mount points to mount logical volumes in other directories.
• Junction Points to mount directories to other directories.
• Symbolic links to mount files and directories to other directories. These were introduced with Vista and support unlike the analysis points mentioned above also references to non-local objects.

Extensions for Windows Vista

Transactional NTFS ( TxF )

With the introduction of Windows Vista, the NTFS file system to the concept of atomic operations (transactions) has been extended. This transaction-based NTFS (English Transactional NTFS in short, TxF ) enables applications to perform file operations atomically. Changes in the file system are therefore only be executed if the entire transaction could be carried out successfully. To a transaction can a single operation or sequence of operations include file ( for example, to create, delete, or rename one or more files or directories ).

Transactional NTFS has been implemented based on the also introduced with Windows Vista Kernel Transaction Manager (KTM ) allowing transactions at the level of the kernel. It extends the already contained in previous versions of NTFS journaling functionality that is limited to the integrity of the structures of the file system to the following:

• Atomic operations on individual files:

• Atomic operations that span multiple files:

• Atomic operations across computer boundaries:

Windows supports transactions from Windows Vista or Windows Server 2008. Meanwhile, however, Microsoft recommends the use of alternatives, must the API are thus considered to be deprecated and discouraged by an insert.

Default cluster sizes and restrictions

Depending on the size of the drive following default cluster sizes will be awarded:

" Not supported ( MBR) " = The Master Boot Record only supports drives up to 2 Tebibyte, beyond the GUID Partition Table is used, which is only supported in Windows 2000 and computers with Extensible Firmware Interface.

Support from other operating systems

Since this is a proprietary file system NTFS, access is possible by operating systems other than the Windows NT - series may be only a limited extent.

Access with DOS -based operating systems

For DOS -based operating systems, including the operating systems Windows 9x series are, exist driving as NTFS4DOS allow full access to NTFS drives.

Access Unix -based operating systems

Linux support via NTFS-3G has full read and write access, read access to encrypted files, and can format disk to NTFS. Furthermore, it is a kernel driver. Mac OS X since version 10.3 read NTFS file systems, but not write. In version 10.6 (Snow Leopard) a hidden write functionality has been found, but which is not officially released.

Under both operating systems can also be accessed through the user-mode driver NTFS-3G write on NTFS file systems. In addition, Paragon a commercial driver.