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NTFS stands for new Technology file system and is the file system of Windows NT, including its successors Windows 2000, Windows XP and Windows server 2003. NTFS inherited many concepts of of IBM file system HPFS, which was used in the operating system OS/2 developed together with Microsoft.

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Compared with FAT NTFS offers among other things a purposeful access protection on file level by complete support of ACCESS control Lists.

Structure

From view of the file system all part of a file is, also the meta data Systems.Die main file is the MFT (master file Table). In this file the entries, which sectors belong to which file, are the access authorizations and the attributes. Each characteristic of a file is under NTFS an attribute, also the actual file content.

Very small files (to approx. 1,4KB) are stored directly in the MFT. Larger files are stored then than attribute in a data run.

When formatting the non removable disk for the MFT a firm size is given. If this is used up, the file system NTFS begins to use free memory from the data medium to, whereby it can come to a fragmenting of the MFT.

When storing a file a journal is led. That means, first the planned action is written into the journal, then the actual write access is implemented to the file and updated finally the journal. If a write access is not completely terminated, for example because of a power failure, the file system must take back only the changes in the journal and is afterwards again in a consistent condition.

NTFS versions

NTFS 1.X - Windows NT 3.51
NTFS 2.X - Windows NT 4.0
NTFS 3,0 - Windows 2000
NTFS 3,1 - Windows XP

Often of NTFS version is falsely spoken 5, and/or 5,1, whereby not the version, but the affiliation to Windows signals the 5 2000 (NT 5) and/or to Windows XP (NT 5,1).

Up-to-date thus NTFS is 3.1

Advantages

efficient memory use with partitions over 400 MT
Journaling Dateisystem: automatic error correction and after data re-establishment crashes.
long file names: File names can be long contrary to FAT16 up to 256 indications and consist of nearly arbitrary university code characters
a maximum length of the complete path name of approx. 32,000 indications
high data security by assignment of rights of access on operating system level
Mechanisms for errortolerant data storage, e.g. "non removable disk reflection"
Maximum file size of theoretically 16 ExaByte
Use of data media with dynamic size (without firm partition table)
snaps and efficient storage of small files (starting from Windows NT 3,51 4 according to standard KB large cluster used)
Storage of alternative data streams
transparent compression of files (only with unencrypted files and cluster sizes to 4kB available)

NTFS 3.X

Data and data medium coding with EFS (not in the XP Home edition and only with unkomprimierten data)
Contingents (also: Disk Quota), in order to limit the usable non removable disk place for individual users
Points of analysis (English Reparse POINT) to the linkage of actions/functions with files and listings, e.g. for
- Hardon the left of: Data can be referenziert by up to 1023 file names (a file, many names).
- NTFS Junction POINTs and/or symbolic left, in order to hang up listings, partitions or drive assemblies into other listings (see Symlinks with Unix/Linux). NTFS Junction POINTs can refer however only to local resources, not to releases of other computers - that is possible only with DFS Junction POINTs.
- Remote STORAGE server
For files with many empty contents - if as Sparse file characterized - only the sections already written are stored.

Disadvantages

file system, i.e. the exact function mode is a trade secret of Microsoft and is observable only against payment
NTFS requires an operating system based on Windows NT
Caused to DOS & Linux
Due to the security concept of NTFS (secure/a logging) is NTFS somewhat more slowly than the FAT Dateisysteme, how strongly the whole affects itself, depends on the computer achievement
NTFS permits alternative of data streams (ADS), in which hides files be put down can and which thus also a danger to represent.
NTFS tried according to standard files the piece to store, nevertheless can come it with many small files to a fragmenting of the MFT. Microsoft provides a Defragmentierungsprogramm, which creates however no considerable Defragmentierung. Even with repeated attempts to defragmentieren the partitions only an insignificant improvement stops itself. Here the user must fall back to products of third manufacturers, be able surely the also very strongly fragmented NTFS partitions (e.g. 90% fragmenting) to defragmentieren and offer more functions than the rather primitive Defragmentierungsprogramm, the Microsoft Windows provides (see also for this "Defragmentierprogramme for NTFS", c't to 21/05).
The smaller cluster sizes make the file system slower. However this can be repaired, by using over the command line formatted and larger cluster sizes (up to 64 KB). However the implemented compression of files functions clearly only with cluster sizes to 4 KB and the internal Fragmentierungsteigt, which leads to storage location speicherplatzverschwendung.
The MFT is a linear structure, which makes accesses relatively inefficient.
The free storage location is administered in bit-maps.
That access platforms like e.g. a Unix/Linux operating system, installed by other restaurants, can lead still often high basic knowledge to overrun and required at present.

NTFS 3.X

Windows NT 4,0 can read NTFS 3.X-Partitionen only starting from service luggage 4.

Standard cluster sizes

Drive assembly size"	Cluster size
512 MT or less	512 bytes
513 MT - 1024 MT	1024 bytes
1025 MT - 2048 MT	2048 bytes
2049 MT and more	4096 bytes

Access with Linux

The Linux Kernel knows 2.2.0 NTFS drive assemblies since version mounten, however without write support. In Linux 2,4 a NTFS driver is contained, which also writes, however serious damage to the file system to arrange can. For the Kernel version 2.6 the NTFS driver was written completely again (developed of Anton Altapamarkov, Cambridge university, and Richard Russon) and offers a revised write support.

Starting from Kernel 2.6.7 only and write protected files already existing could not be changed or overwritten surely, if the file size does not change thereby. Putting on or deletion of files or listings is not supported yet.

Since Kernel 2.6.12 is not than experimentally designated the NTFS any more.

At present also a free program complex exists named Captive, which uses the original drivers of Windows (XP/2003) and them an Windows environment simulated. Therefore this driver is high compatible, in addition, slower than a native driver. For the legal employment of the original drivers a Windows license is necessary.

Since Kernel 2.6.15 also changing of files with change of the file size is possible. Creation and deletion of files are not supported by the NTFS Kerneltreiber yet. It exists however a FUSE module, with which one can provide and delete files and listings. In addition, no data are not functioned always destroyed.

Further there is a commercial product NTFS for Linux 3 of Paragon, which was introduced in the Linux magazine 11/04. It can damage however the file system, in particular with NTFS 3.x.

Access with DOS

For DOS systems (e.g. boat disks) can one limited NTFS access to attain. The company Sysinternals offers drivers named NTFSDOS, which can however only read in the free version. The enterprise DATA pole makes a free NTFS driver available for DOS with write access.