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NTFS
Developer Microsoft
Full name NTFS
Introduced July 1993 (Windows NT 3.1)
Partition identifier 0x07 (MBR)
EBD0A0A2-B9E5-4433-87C0-68B6B72699C7 (GPT)
Structures
Directory contents B+ tree[1]
File allocation Bitmap/Extents
Bad blocks Bitmap/Extents
Limits
Max file size 264 bytes (16 EiB) minus 1 KiB [2]
Max number of files 4,294,967,295 (232-1)[2]
Max filename length 255 UTF-16 code units[3]
Max volume size 264 − 1 clusters [2]
Allowed characters in filenames In Posix namespace, any UTF-16 code unit (case sensitive) except U+0000 (NUL) and / (slash). A software developer is a person or organization concerned with facets of the software development process wider than design and coding a somewhat broader scope of Microsoft Corporation is an American multinational Computer technology Corporation, which rose to dominate the Home computer Windows NT 31 is the first release of Microsoft 's Windows NT line of server and business desktop Operating systems and was released to Disk partitioning is the creation of separate divisions of a Hard disk drive using Partition editors Once a disk is divided into several partitions directories and MBRs and disk partitioning MBRs and system bootstrapping On IA-32 IBM PC compatible machines using the MBR Partition Table scheme the bootstrapping In Computer hardware, GUID Partition Table ( GPT) is a standard for the layout of the Partition table on a physical Hard disk. In Computer science, a B+ tree is a type of tree which represents sorted data in a way that allows for efficient insertion retrieval and removal of records An exbibyte (a contraction of ex a bi nary byte) is a unit of Information or Computer storage, abbreviated EiB. A kibibyte (a contraction of ki lo bi nary byte) is a unit of Information or Computer storage, established by the International In Computing, UTF-16 (16- Bit Unicode Transformation Format is a variable-length Character encoding for Unicode, capable of encoding POSIX (ˈpɒzɪks or "Portable Operating System Interface" is the collective name of a family of related standards specified by the IEEE to define In Computing, UTF-16 (16- Bit Unicode Transformation Format is a variable-length Character encoding for Unicode, capable of encoding The null character (also null terminator) is a character with the value zero present in the ASCII and Unicode character sets and available In Win32 namespace, any UTF-16 code unit (case insensitive) except U+0000 (NUL) / (slash) \ (backslash) : (colon) * (asterisk) ? (Question mark) " (quote) < (less than) > (greater than) and | (pipe) [3]
Features
Dates recorded Creation, modification, POSIX change, access
Date range 1 January 1601 – 28 May 60056 (File times are 64-bit numbers counting 100-nanosecond intervals (ten million per second) since 1601, which is 58,000+ years)
Date resolution 100ns
Forks Yes (see Alternate data streams below)
Attributes Read-only, hidden, system, archive, not content indexed, off-line, temporary
File system permissions ACLs
Transparent compression Per-file, LZ77 (Windows NT 3.51 onward)
Transparent encryption Per-file,
DESX (Windows 2000 onward),
Triple DES (Windows XP onward),
AES (Windows XP Service Pack 1, Windows Server 2003 onward)
Supported operating systems Windows NT family (Windows NT 3.1 to Windows NT 4.0, Windows 2000, Windows XP, Windows Server 2003, Windows Vista, Windows Server 2008)

NTFS (New Technology File System) is the standard file system of Windows NT, including its later versions Windows 2000, Windows XP, Windows Server 2003, Windows Server 2008, and Windows Vista. In Computing, UTF-16 (16- Bit Unicode Transformation Format is a variable-length Character encoding for Unicode, capable of encoding The null character (also null terminator) is a character with the value zero present in the ASCII and Unicode character sets and available The backslash ( \) is a typographical mark ( Glyph) used chiefly in Computing. An asterisk ( *) (Latin asteriscum "little star" from Greek ἀστερίσκος) is a Typographical symbol or Glyph The question mark (? also known as an interrogation point, question point, query, or eroteme, is a punctuation mark that replaces Brackets are Punctuation marks used in pairs to set apart or interject text within other text Brackets are Punctuation marks used in pairs to set apart or interject text within other text Note "broken bar" and the glyph "¦" redirect here New Year See also New Year The Ancient Romans began their consular year on January 1st since 153 BC Events 585 BC - A Solar eclipse occurs as predicted by Greek philosopher and scientist Thales, while Alyattes is battling In computer File systems a fork is additional data associated with a file system object Most modern File systems have methods of administering permissions or access rights to specific users and groups of users In Computer security, an access control list ( ACL) is a list of permissions attached to an object LZ77 and LZ78 are the names for the two Lossless data compression Algorithms published in papers by Abraham Lempel and Jacob Ziv in Windows NT is a family of Operating systems produced by Microsoft, the first version of which was released in July 1993 Filesystem-level encryption, often called file or folder encryption is a form of Disk encryption where individual files or directories are encrypted by the File In Cryptography, DES-X (or DESX) is a variant on the DES (Data Encryption Standard Block cipher intended to increase the complexity of a Windows 2000 (also referred to as Win2K) is a preemptive, interruptible graphical and business-oriented Operating system designed to work with In Cryptography, Triple DES is a Block cipher formed from the Data Encryption Standard (DES Cipher by using it three times Windows XP is a family of 32-bit and 64-bit Operating systems produced by Microsoft for use on Personal computers including home and In Cryptography, the Advanced Encryption Standard ( AES) also known as Rijndael, is a Block cipher adopted as an Encryption Windows Server 2003 (also referred to as Win2K3 is a server Operating system produced by Microsoft. An operating system (commonly abbreviated OS and O/S) is the software component of a Computer system that is responsible for the management and coordination Windows NT is a family of Operating systems produced by Microsoft, the first version of which was released in July 1993 Windows NT 31 is the first release of Microsoft 's Windows NT line of server and business desktop Operating systems and was released to Windows NT 40 is a preemptive, graphical and business-oriented Operating system designed to work with either Uniprocessor or symmetric Windows 2000 (also referred to as Win2K) is a preemptive, interruptible graphical and business-oriented Operating system designed to work with Windows XP is a family of 32-bit and 64-bit Operating systems produced by Microsoft for use on Personal computers including home and Windows Server 2003 (also referred to as Win2K3 is a server Operating system produced by Microsoft. Windows Vista (ˈvɪstə is a line of Operating systems developed by Microsoft for use on Personal computers including home and business desktops Windows Server 2008 is the most recent release of Microsoft Windows ' server line of Operating systems Released to manufacturing on 4 February In Computing, a file system (often also written as filesystem) is a method for storing and organizing Computer files and the data they contain to make Windows NT is a family of Operating systems produced by Microsoft, the first version of which was released in July 1993 Windows 2000 (also referred to as Win2K) is a preemptive, interruptible graphical and business-oriented Operating system designed to work with Windows XP is a family of 32-bit and 64-bit Operating systems produced by Microsoft for use on Personal computers including home and Windows Server 2003 (also referred to as Win2K3 is a server Operating system produced by Microsoft. Windows Server 2008 is the most recent release of Microsoft Windows ' server line of Operating systems Released to manufacturing on 4 February Windows Vista (ˈvɪstə is a line of Operating systems developed by Microsoft for use on Personal computers including home and business desktops [4]

NTFS follows the FAT file system as the preferred file system for Microsoft’s “Windows”-branded operating systems. Templateinfobox filesystem whilst covering all 3 file systems please make any style changes to both at the same time NTFS has several improvements over FAT and HPFS (High Performance File System) such as improved support for metadata and the use of advanced data structures to improve performance, reliability, and disk space utilization, plus additional extensions such as security access control lists (ACL) and file system journaling. HPFS or High Performance File System is a File system created specifically for the OS/2 Operating system to improve upon the limitations Metadata ( meta data, or sometimes metainformation) is "data about data" of any sort in any media In Computer security, an access control list ( ACL) is a list of permissions attached to an object A journaling file system is a File system that logs changes to a journal (usually a circular log in a dedicated area before committing them to the main file The exact file system specification is a trade secret, although (since NTFS v3. A trade secret is a Formula, practice, Process, Design, instrument, Pattern, or compilation of Information which 00) it can be licensed commercially from Microsoft through their Intellectual Property Licensing program. Intellectual property ( IP) is a legal field that refers to creations of the mind such as musical literary and artistic works inventions and symbols names

Contents

History

In the early 1990s Microsoft and IBM formed a joint project to create the next generation graphical operating system. International Business Machines Corporation abbreviated IBM and nicknamed "Big Blue", is a multinational Computer Technology An operating system (commonly abbreviated OS and O/S) is the software component of a Computer system that is responsible for the management and coordination The result of the project was OS/2, but eventually Microsoft and IBM disagreed on many important issues and separated. OS/2 is a computer Operating system, initially created by Microsoft and IBM, then later developed by IBM exclusively OS/2 remained an IBM project. Microsoft started to work on Windows NT. The OS/2 filesystem HPFS contained several important features. HPFS or High Performance File System is a File system created specifically for the OS/2 Operating system to improve upon the limitations When Microsoft created their new operating system, they borrowed many of these concepts for NTFS. [5] Perhaps as a result of this, HPFS and NTFS share the same disk partition identification type code (07). Disk partitioning is the creation of separate divisions of a Hard disk drive using Partition editors Once a disk is divided into several partitions directories and This is unusual since the other major filesystems have their own code; FAT has more than nine (one each for FAT12, FAT16, FAT32, etc. Templateinfobox filesystem whilst covering all 3 file systems please make any style changes to both at the same time Templateinfobox filesystem whilst covering all 3 file systems please make any style changes to both at the same time Templateinfobox filesystem whilst covering all 3 file systems please make any style changes to both at the same time ). To identify the type of filesystem in a partition type 07, additional checks are needed.

Versions

NTFS has five released versions: (the alternate names are due to the fact that the OS version is sometimes set in line with the NTFS version)

V1. Windows Server 2008 is the most recent release of Microsoft Windows ' server line of Operating systems Released to manufacturing on 4 February 0 and V1. 2 are incompatible: that is, volumes written by NT 3. 5x cannot be read by NT 3. 1 until an update on the NT 3. 5x CD is applied to NT 3. 1, which also adds FAT long file name support. [6] V1. 2 supported compressed files, named streams, ACL-based security, etc. [7] V3. 0 added disk quotas, encryption, sparse files, reparse points, update sequence number (USN) journaling, the $Extend folder and its files, and reorganized security descriptors so that multiple files which use the same security setting can share the same descriptor. [8] V3. 1 expanded the Master File Table (MFT) entries with redundant MFT record number (useful for recovering damaged MFT files).

Windows Vista introduced Transactional NTFS, NTFS symbolic links, and self-healing functionality[9] though those owe more to additional functionality of the operating system than the filesystem itself. Windows Vista (ˈvɪstə is a line of Operating systems developed by Microsoft for use on Personal computers including home and business desktops Transactional NTFS (abbreviated TxF is a component of Windows Vista and later operating systems An NTFS symbolic link (symlink is a file-system object in the NTFS filesystem that points to another file system object Yet the NTFS version number has not been raised.

Features

NTFS v3. 0, the third version of NTFS to be introduced, includes several new features over its predecessors: disk usage quotas, sparse file support, reparse points, distributed link tracking and file-level encryption, also known as the Encrypting File System (EFS).

Alternate data streams (ADS) 
Alternate data streams allows files to be associated with more than one data stream. In computer File systems a fork is additional data associated with a file system object For example, a file such as text. txt can have an ADS with the name of text. txt:secret (of form filename:streamname) that can only be accessed by knowing the ADS name or by specialized directory browsing programs. Alternate streams are not detectable in the original file's size but are lost when the original file (i. e. text. txt) is deleted with a RemoveFile or RemoveFileTransacted call (or a call that uses those calls), or when the file is copied or moved to a partition that doesn't support ADS (e. g. a FAT partition, a floppy disk, or a network share). While ADS is a useful feature, it can also easily eat up hard disk space if unknown either through being forgotten or not being detected.
Quotas 
Disk quotas were introduced in NTFS v3. A disk quota is a limit set by a System administrator that restricts certain aspects of File system usage on modern Operating systems Types of They allow the administrator of a computer that runs a version of Windows that supports NTFS to set a threshold of disk space that users may utilize. It also allows administrators to keep track of how much disk space each user is using. An administrator may specify a certain level of disk space that a user may use before they receive a warning, and then deny access to the user once they hit their upper limit of space. Disk quotas do not take into account NTFS's transparent file-compression, should this be enabled. Applications that query the amount of free space will also see the amount of free space left to the user who has a quota applied to them.
Sparse files 
Sparse files are files which contain sparse data sets, data mostly filled with zeroes. In Computer science, a sparse file is a type of Computer file that attempts to use File system space more efficiently when blocks allocated to the file In the mathematical subfield of Numerical analysis a sparse matrix is a matrix populated primarily with zeros Many scientific applications can generate very large sparse data sets. Because of this, Microsoft has implemented support for sparse files by allowing an application to specify regions of empty (zero) data. An application that reads a sparse file reads it in the normal manner with the file system calculating what data should be returned based upon the file offset. As with compressed files, the actual size of sparse files are not taken into account when determining quota limits. [10][11]
Reparse points 
This feature was introduced in NTFS v3. These are used by associating a reparse tag in the user space attribute of a file or directory. When the object manager (see Windows NT line executive) parses a file system name lookup and encounters a reparse attribute, it knows to reparse the name lookup, passing the user controlled reparse data to every file system filter driver that is loaded into Windows 2000. Windows NT 31, Windows NT 35, Windows NT 351, Windows NT 40, Windows 2000, Windows XP, Windows Server 2003, Windows Each filter driver examines the reparse data to see if it is associated with that reparse point, and if that filter driver determines a match then it intercepts the file system call and executes its special functionality. Reparse points are used to implement Volume Mount Points, Directory Junctions, Hierarchical Storage Management, Native Structured Storage and Single Instance Storage:
Volume mount points 
Similar to Unix mount points, where the root of another file system is attached to a directory. Unix (officially trademarked as UNIX, sometimes also written as Unix with Small caps) is a computer Mounting, in Computer science, is the process of making a File system ready for use by the Operating system, typically by reading certain index data structures In NTFS, this allows additional file systems to be mounted without requiring a separate drive letter (like C: or D:) for each.
Directory Junctions 
Similar to Volume Mount Points, however directory junctions reference other directories in the file system instead of other volumes. An NTFS junction point (JP is a feature of the NTFS File system version 3 For instance, the directory C:\exampledir with a directory junction attribute that contains a link to D:\linkeddir will automatically refer to the directory D:\linkeddir when it is accessed by a user-mode application. [12] This function is conceptually similar to symbolic links to directories in Unix except that the target in NTFS must always be another directory. Unix (officially trademarked as UNIX, sometimes also written as Unix with Small caps) is a computer (Typical Unix file systems allow the target of a symbolic link to be any type of file. )
Hard links 
Originally included to support the POSIX subsystem in Windows NT[13], hard links are similar to directory junctions, but used for files instead of directories. POSIX (ˈpɒzɪks or "Portable Operating System Interface" is the collective name of a family of related standards specified by the IEEE to define In Computing, a hard link is a directory reference or pointer to a file on a storage volume Hard links can only be applied to files on the same volume since an additional filename record is added to the file's MFT record. Short (8. 3) filenames are also implemented as additional filename records that don't have separate directory entries.
Hierarchical Storage Management (HSM) 
Hierarchical Storage Management is a means of transferring files that are not used for some period of time to less expensive storage media. Hierarchical Storage Management ( HSM) is a data storage technique which automatically moves data between high-cost and low-cost storage media When the file is next accessed the reparse point on that file determines that it is needed and retrieves it from storage.
Native Structured Storage (NSS) 
NSS was an ActiveX document storage technology that has since been discontinued by Microsoft. ActiveX is a Component object model (COM developed by Microsoft for Windows. It allowed ActiveX Documents to be stored in the same multi-stream format that ActiveX uses internally. ActiveX Document (also known as DocObject or DocObj) is a Compound document architecture that allow a container application to use the full capabilities An NSS file system filter was loaded and used to process the multiple streams transparently to the application, and when the file was transferred to a non-NTFS formatted disk volume it would also transfer the multiple streams into a single stream. [14]
Volume Shadow Copy 
The Volume Shadow Copy (VSC) service keeps historical versions of files and folders on NTFS volumes by copying old, newly-overwritten data to shadow copy (copy-on-write). Shadow Copy (also called Volume Snapshot Service or VSS, or Previous Versions in Windows Vista) is a feature introduced with Windows XP Copy-on-write (sometimes referred to as "COW" is an optimization strategy used in Computer programming. The old file data is overlaid on the new when the user requests a revert to an earlier version. This also allows data backup programs to archive files currently in use by the file system. On heavily loaded systems, Microsoft recommends setting up a shadow copy volume on separate disk to reduce the I/O load on the main volume.
File compression 
NTFS can compress files using a variant of the LZ77 algorithm (also used in the popular ZIP file format). LZ77 and LZ78 are the names for the two Lossless data compression Algorithms published in papers by Abraham Lempel and Jacob Ziv in The ZIP File format is a Data compression and archival format. [15] Although read-write access to compressed files is transparent, Microsoft recommends avoiding compression on server systems and/or network shares holding roaming profiles because it puts a considerable load on the processor. Any change in a Computing system such as new feature or new component is transparent if the system after change adheres to previous external interface as much as [16]
Single-user systems with limited hard disk space will probably use NTFS compression successfully. The slowest link in a notebook is not the CPU but the speed of the hard drive, so NTFS compression allows the limited, slow storage space to be better used, in terms of both space and (often) speed. [17] NTFS compression can also serve as a replacement for sparse files when a program (e. g. a download manager) is not able to create files without content as sparse files. A download manager is a Computer program dedicated to the task of downloading (and sometimes uploading) possibly unrelated stand-alone files from (and
Single Instance Storage (SIS) 
When there are several directories that have different, but similar, files, some of these files may have identical content. Single instance storage allows identical files to be merged to one file and create references to that merged file. Single-instance storage is a system's ability to keep one copy of content that multiple users or computers share SIS consists of a file system filter that manages copies, modification and merges to files; and a user space service (or groveler) that searches for files that are identical and need merging. SIS was mainly designed for remote installation servers as these may have multiple installation images that contain many identical files; SIS allows these to be consolidated but, unlike for example hard links, each file remains distinct; changes to one copy of a file will leave others unaltered. This is similar to copy-on-write, which is a technique by which memory copying is not really done until one copy is modified. Copy-on-write (sometimes referred to as "COW" is an optimization strategy used in Computer programming. [18]
Encrypting File System (EFS) 
EFS provides strong and user-transparent encryption of any file or folder on an NTFS volume. The Encrypting File System (EFS is a file system driver that provides Filesystem-level encryption in Microsoft Windows ( 2000 and later operating EFS works in conjunction with the EFS service, Microsoft's CryptoAPI and the EFS File System Run-Time Library (FSRTL). The Cryptographic Application Programming Interface (also known variously as CryptoAPI, Microsoft Cryptography API, or simply CAPI) is an Application
EFS works by encrypting a file with a bulk symmetric key (also known as the File Encryption Key, or FEK), which is used because it takes a relatively smaller amount of time to encrypt and decrypt large amounts of data than if an asymmetric key cipher is used. Symmetric-key algorithms are a class of Algorithms for Cryptography that use trivially related often identical Cryptographic keys for both decryption Public-key cryptography, also known as asymmetric cryptography, is a form of Cryptography in which the key used to encrypt a message differs from the key The symmetric key that is used to encrypt the file is then encrypted with a public key that is associated with the user who encrypted the file, and this encrypted data is stored in an alternate data stream of the encrypted file. Public-key cryptography, also known as asymmetric cryptography, is a form of Cryptography in which the key used to encrypt a message differs from the key To decrypt the file, the file system uses the private key of the user to decrypt the symmetric key that is stored in the file header. It then uses the symmetric key to decrypt the file. Because this is done at the file system level, it is transparent to the user. [19] Also, in case of a user losing access to their key, support for recovery agents that can unencrypt files has been built in to the EFS system.
Symbolic links 
Symbolic links were originally used to support the POSIX subsystem in Windows NT. In Computing, a symbolic link (also symlink or soft link) is a special type of file that contains a reference to another POSIX (ˈpɒzɪks or "Portable Operating System Interface" is the collective name of a family of related standards specified by the IEEE to define Symbolic links (or Soft links) are resolved on the client side. So when a symbolic link is shared, the target is subject to the access restrictions on the client, and not the server.
Transactional NTFS 
As of Windows Vista, applications can use Transactional NTFS to group changes to files together into a transaction. Transactional NTFS (abbreviated TxF is a component of Windows Vista and later operating systems The transaction will guarantee that all changes happen, or none of them do, and it will guarantee that applications outside the transaction will not see the changes until the precise instant they're committed. [20]
Change Journal 
Record the changes of files.

Interoperability

Details on the implementation's internals are closed, which makes it difficult for third-party vendors to provide tools to handle NTFS.

Linux

Full and safe read/write of NTFS is provided by the NTFS-3G driver. NTFS-3G is an Open source Cross-platform implementation of the Microsoft Windows NTFS file system with read-write support It is included in most Linux distributions. A Linux distribution (also called GNU/Linux by distributions such as Debian, Fedora, Ubuntu, Linux Mint, Mandriva and

Other outdated and mostly read-only solutions exist as well:

Note that all three userspace drivers, namely NTFSMount, NTFS-3G and Captive NTFS, are built on the Filesystem in Userspace (FUSE), a Linux kernel module tasked with bridging userspace and kernel code to save and retrieve data. Filesystem in Userspace ( FUSE) is a Loadable kernel module for Unix-like computer Operating systems that allows non-privileged users to create

Almost all drivers listed above (except Paragon NTFS for Linux) are open source (GPL). Open source is a development methodology which offers practical accessibility to a product's source (goods and knowledge Due to the complexity of internal NTFS structures, both the built-in 2. 6. 14 kernel driver and the FUSE drivers disallow changes to the volume that are considered unsafe, to avoid corruption.

Windows

While the different NTFS versions have a great degree of both forward and backward compatibility, there are technical considerations for mounting newer NTFS volumes in older versions of Windows. Forward compatibility (sometimes confused with Extensibility) is the ability of a system to gracefully accept Input intended for later versions of itself In Technology, especially Computing (irrespective of platform a product is said to be backward compatible when it is able to take the place of an older product This affects dual-booting, and external portable hard drives.

For example, "Previous Versions" (a. k. a. Volume Shadow Copy) are lost because the older OS doesn't understand how to keep the new features' data updated. Shadow Copy (also called Volume Snapshot Service or VSS, or Previous Versions in Windows Vista) is a feature introduced with Windows XP [22]

Others

eComStation, KolibriOS, and Mac OS X versions 10. eComStation is a PC Operating system based on OS/2, published by Serenity Systems, USA KolibriOS (also known as KOS and Kolibri) is a free Operating system with a monolithic preemptive, real-time Mac OS X (mæk oʊ ɛs tɛn is a line of computer Operating systems developed marketed and sold by Apple Inc, the latest of which is pre-loaded on all currently 3 and later offer read-only NTFS support (there is a beta NTFS driver that allows write/delete for eComStation, but is generally considered unsafe). A free third-party tool for BeOS, which was based on NTFS-3G, allows full NTFS read and write. BeOS is an Operating system for Personal computers which began development by Be Inc

NTFS-3G also works on Mac OS X, FreeBSD, NetBSD and Haiku besides Linux. NTFS-3G is an Open source Cross-platform implementation of the Microsoft Windows NTFS file system with read-write support

A commercial read/write driver for DOS called "NTFS4DOS" also exists. [1]

A commercial solution for Mac OS X with read/write access is "Paragon NTFS for Mac OS X". [2]

Compatibility with FAT

Microsoft currently provides a tool (convert. exe) to convert HPFS (only on Windows NT 3), FAT16 and, on Windows 2000 and higher, FAT32 to NTFS, but not the other way around. HPFS or High Performance File System is a File system created specifically for the OS/2 Operating system to improve upon the limitations Templateinfobox filesystem whilst covering all 3 file systems please make any style changes to both at the same time [23] Various third-party tools are all capable of safely resizing NTFS partitions. Microsoft added the ability to shrink or expand a partition with Windows Vista, but this capability is limited because it will not relocate the master file table, thus limiting the ability to shrink a partition to roughly half of its original size. Windows Vista (ˈvɪstə is a line of Operating systems developed by Microsoft for use on Personal computers including home and business desktops [24]

For historical reasons, the versions of Windows that do not support NTFS all keep time internally as local zone time, and therefore so do all file systems other than NTFS that are supported by current versions of Windows. However, Windows NT and its descendants keep internal timestamps as UTC and make the appropriate conversions for display purposes. Therefore, NTFS timestamps are in UTC. This means that when files are copied or moved between NTFS and non-NTFS partitions, the OS needs to convert timestamps on the fly. But if some files are moved when daylight saving time (DST) is in effect, and other files are moved when standard time is in effect, there can be some ambiguities in the conversions. Daylight saving time ( DST Standard time is the result of synchronizing clocks in different geographical locations within a Time zone to the same time rather than using the local meridian as As a result, especially shortly after one of the days on which local zone time changes, users may observe that some files have timestamps that are incorrect by one hour. Due to the differences in implementation of DST between the northern and southern hemispheres, this can result in a potential timestamp error of up to 4 hours in any given 12 months. [25]

Internals

In NTFS, all file data—file name, creation date, access permissions, and contents—are stored as metadata. A computer file is a block of Arbitrary Information, or resource for storing information which is available to a Computer program and is usually Metadata ( meta data, or sometimes metainformation) is "data about data" of any sort in any media This abstract approach allowed easy addition of file system features during Windows NT's development — an interesting example is the addition of fields for indexing used by the Active Directory software. Active Directory ( AD) is a technology created by Microsoft that provides a variety of network services including LDAP -like Directory

NTFS allows any sequence of 16-bit values for name encoding (file names, stream names, index names, etc. ). This means UTF-16 codepoints are supported, but the file system does not check whether a sequence is valid UTF-16 (it allows any sequence of short values, not restricted to those in the Unicode standard). In Computing, UTF-16 (16- Bit Unicode Transformation Format is a variable-length Character encoding for Unicode, capable of encoding

Internally, NTFS uses B+ trees to index file system data. In Computer science, a B+ tree is a type of tree which represents sorted data in a way that allows for efficient insertion retrieval and removal of records Although complex to implement, this allows faster file look up times in most cases. A file system journal is used to guarantee the integrity of the file system—but not individual files' content. Systems using NTFS are known to have improved reliability compared to FAT file systems. [26]

The Master File Table (MFT) contains metadata about every file, directory, and metafile on an NTFS volume. Metadata ( meta data, or sometimes metainformation) is "data about data" of any sort in any media It includes filenames, locations, size, and permissions. Its structure supports algorithms which minimize disk fragmentation. In computing file system fragmentation, sometimes called file system aging, is the inability of a File system to lay out related data sequentially (contiguously A directory entry consists of a filename and a "file ID" which is the record number representing the file in the Master File Table. The file ID also contains a reuse count to detect stale references. While this strongly resembles the W_FID of Files-11, other NTFS structures radically differ. Files-11, also known as on-disk structure, is the File system used by Hewlett-Packard 's OpenVMS Operating system, and also (in a simpler

Metafiles

NTFS contains several files which define and organize the file system. In all respects, most of these files are structured like any other user file ($Volume being the most peculiar), but are not of direct interest to file system clients. These metafiles define files, back up critical file system data, buffer file system changes, manage free space allocation, satisfy BIOS expectations, track bad allocation units, and store security and disk space usage information. In Computing, the BIOS (ˈbaɪoʊs

Segment Number File Name Purpose
0 $MFT Describes all files on the volume, including file names, timestamps, stream names and lists of cluster numbers where data streams reside, indexes, security identifiers, and file attributes like "read only", "compressed", "encrypted", etc.
1 $MFTMirr Is a duplicate of the first vital entries of $MFT, usually 4 entries (4 KiB).
2 $LogFile Contains transaction log of file system changes for metadata consistency.
3 $Volume Contains information about the volume, namely the volume object identifier, volume label, file system version, and volume flags (mounted, chkdsk requested, requested $LogFile resize, mounted on NT 4, volume serial number updating, structure upgrade request). In the context of computer Operating systems volume is the term used to describe a single accessible storage area with a single File system, typically (though not The volume serial number is in $Boot file.
4 $AttrDef A table of NTFS attributes used with names, numbers and descriptions.
5 . Root directory. In computer File systems the root directory is the first or top-most directory in a hierarchy
6 $Bitmap A table of bit entries representing if particular cluster on the volume is used or free.
7 $Boot Volume boot record. A Volume Boot Record (also known as a volume boot sector or a partition boot sector, although the latter is not strictly correct is a type of Boot sector This file located at first cluster on the volume includes bootstrap code (used to find and launch NTLDR/ BOOTMGR and a BIOS parameter block including volume serial number and cluster numbers of $MFT and $MFTMirr. NTLDR ( Abbreviation of NT Loader) is the boot loader for all releases of Microsoft 's Windows NT This refers to the boot components for Windows Vista and Windows Server 2008. BIOS parameter block ( BPB) is a description of the physical medium ( Hard disk or floppy that might be stored in a partition's Volume Boot Record. A volume serial number is a Serial number assigned to a disk volume or tape volume.
8 $BadClus A file which contains all the clusters marked as having bad sectors. A bad sector is a sector on a computer's Disk drive that cannot be used due to permanent damage such as physical damage to the disk particles This file simplifies cluster management by the chkdsk utility, both as a place to put newly discovered bad sectors, and for identifying unreferenced clusters.
9 $Secure Access control list database which reduces overhead having many identical ACLs stored with each file, by uniquely storing these ACLs in this database only (contains two indices $SII: perhaps Security ID Index and $SDH: Security Descriptor Hash which index the stream named $SDS containing actual ACL table). In Computer security, an access control list ( ACL) is a list of permissions attached to an object [27]
10 $UpCase A table of unicode uppercased characters for ensuring case insensitivity in Win32 and DOS namespaces.
11 $Extend A filesystem directory containing various optional extensions, such as $Quota, $ObjId, $Reparse or $UsnJrnl.
12 . . . 23 Reserved.
usually 24 $Extend\$Quota Contains information regarding disk quotas.
usually 25 $Extend\$ObjId Contains information used for distributed link tracking.
usually 26 $Extend\$Reparse Contains backreferences of all reparse points (such as symbolic links) on the volume
27 . In Computing, a symbolic link (also symlink or soft link) is a special type of file that contains a reference to another . . file. ext Beginning of regular file entries.

These metafiles are treated specially by NTFS and are difficult to directly view: special purpose-built tools are needed.

Resident vs. non-resident files

To optimize storage for the common case of small data files, NTFS prefers to place file data within the master file table—if it fits, instead of using MFT space to list clusters containing the data. The former is called "resident data" by computer forensics workers. Computer forensics is a branch of Forensic science pertaining to legal evidence found in computers and digital storage mediums The amount of data which fits is highly dependent on the file's characteristics, but 700 to 800 bytes is common in single-stream files with non-lengthy filenames and no ACLs. Encrypted-by-NTFS, sparse, or compressed files cannot be resident.

Since resident files do not directly occupy clusters ("allocation units"), it is possible for an NTFS volume to contain more files on a volume than there are clusters. For example, an 80 GB (74. 5 GiB) partition NTFS formats with 19,543,064 clusters of 4 KiB. Subtracting system files (64 MiB log file, a 2,442,888-byte $Bitmap file, and about 25 clusters of fixed overhead) leaves 19,526,158 clusters free for files and indices. Since there are four MFT records per cluster, this volume theoretically could hold almost 4 × 19,526,158 = 78,104,632 resident files.

Limitations

The following are a few limitations of NTFS:

Reserved File Names
Though the file system supports paths up to about 32767 Unicode characters[28] with each path component (directory or filename) up to 255 characters[28] long, certain names are unusable, since NTFS stores its metadata in regular (albeit hidden and for the most part inaccessible) files; accordingly, user files cannot use these names. These files are all in the root directory of a volume (and are reserved only for that directory). The names are: $MFT, $MFTMirr, $LogFile, $Volume, $AttrDef, . (dot), $Bitmap, $Boot, $BadClus, $Secure, $Upcase, and $Extend;[2] . (dot) and $Extend are both directories; the others are files.
Maximum Volume Size
In theory, the maximum NTFS volume size is 264-1 clusters. However, the maximum NTFS volume size as implemented in Windows XP Professional is 232-1 clusters. For example, using 64 KiB clusters, the maximum NTFS volume size is 256 TiB minus 64 KiB. A kibibyte (a contraction of ki lo bi nary byte) is a unit of Information or Computer storage, established by the International Using the default cluster size of 4 KiB, the maximum NTFS volume size is 16 TiB minus 4 KiB. Because partition tables on master boot record (MBR) disks only support partition sizes up to 2 TiB, dynamic or GPT volumes must be used to create bootable NTFS volumes over 2 TiB. In Computer hardware, GUID Partition Table ( GPT) is a standard for the layout of the Partition table on a physical Hard disk.
Maximum File Size
Theoretical: 16 EiB minus 1 KiB (264 − 210 bytes). An exbibyte (a contraction of ex a bi nary byte) is a unit of Information or Computer storage, abbreviated EiB. Implementation: 16 TiB minus 64 KiB (244 − 216 bytes)
Alternate Data Streams
Windows system calls may—or may not—handle alternate data streams. A tebibyte (a contraction of te ra bi nary byte) is a unit of Information or Computer storage, abbreviated TiB. [2] Depending on the operating system, utility and remote file system, a file transfer might silently strip data streams. [2] A safe way of copying or moving files is to use the BackupRead and BackupWrite system calls, which allow programs to enumerate streams, to verify whether each stream should be written to the destination volume and to knowingly skip offending streams. [2]
Maximum path length
An absolute path may be up to 32767 characters[28] long; a relative path is limited to 255 characters.
Date range
NTFS uses the same time reckoning as Windows NT: 64-bit timestamps with a range from January 1, 1601 to May 28 60056 at a resolution of ten million ticks per second. New Year See also New Year The Ancient Romans began their consular year on January 1st since 153 BC Events 585 BC - A Solar eclipse occurs as predicted by Greek philosopher and scientist Thales, while Alyattes is battling

Developers

NTFS developers include:

References

  1. ^ Mark Russinovich. Tom Miller (born in 1950) is a Software developer who is employed by Microsoft. Gary Dean Kimura is a Professor for the Department of Computer Science & Engineering at the University of Washington and a Software developer who worked Mark Russinovich is a Software engineer and Author who works for Microsoft as a Technical fellow. Inside Win2K NTFS, Part 1. Microsoft Developer Network. The Microsoft Developer Network ( MSDN) is the portion of Microsoft responsible for managing the firm's relationship with developers hardware developers interested Retrieved on 2008-04-18. 2008 ( MMVIII) is the current year in accordance with the Gregorian calendar, a Leap year that started on Tuesday of the Common Events 1025 - Bolesław Chrobry is crowned in Gniezno, becoming the first King of Poland.
  2. ^ a b c d e f g Microsoft Corporation. How NTFS Works. Retrieved on 2008-01-27. 2008 ( MMVIII) is the current year in accordance with the Gregorian calendar, a Leap year that started on Tuesday of the Common Events 98 - Trajan becomes Roman Emperor after the death of Nerva.
  3. ^ a b Richard Russon and Yuval Fledel. NTFS Documentation. Retrieved on 2007-07-01. Year 2007 ( MMVII) was a Common year starting on Monday of the Gregorian calendar in the 21st century. "July 1st" redirects here For the Ayumi Hamasaki song see H (song.
  4. ^ Custer, Helen (1994). Inside the Windows NT File System. Microsoft Press. Microsoft Press is the Publishing arm of Microsoft, usually releasing books dealing with various current Microsoft technologies ISBN 978-1-55615-660-1.  
  5. ^ Kozierok, Charles M. (April 17, 2001). Overview and History of NTFS. PCGuide.
  6. ^ Recovering Windows NT After a Boot Failure on an NTFS Drive. Microsoft (November 1, 2006).
  7. ^ Inside Win2K NTFS, Part 1,page1 ohg2001
  8. ^ Inside Win2K NTFS, Part 1
  9. ^ Loveall, John (2006). Storage improvements in Windows Vista and Windows Server 2008 (PowerPoint) 14-20. Microsoft Corporation. Retrieved on 2007-09-04. Year 2007 ( MMVII) was a Common year starting on Monday of the Gregorian calendar in the 21st century. Events 476 - Romulus Augustus, last emperor of the Western Roman Empire, is deposed when Odoacer proclaims himself
  10. ^ Sparse Files. MSDN Platform SDK: File Systems. Retrieved on 2005-05-22. Year 2005 ( MMV) was a Common year starting on Saturday (link displays full calendar of the Gregorian calendar. Events 334 BC - The Greek army of Alexander the Great defeats Darius III of Persia in the Battle of the Granicus.
  11. ^ Sparse FIles and Disk Quotas. Win32 and COM Development: File Systems. Retrieved on 2007-12-05. Year 2007 ( MMVII) was a Common year starting on Monday of the Gregorian calendar in the 21st century. Events 63 BC - Cicero reads the last of his Catiline Orations.
  12. ^ Mark Russinovich, "Inside Win2K NTFS, Part 1"
  13. ^ MS Windows NT Workstation 4. 0 Resource Guide, "POSIX Compatibility"
  14. ^ John Saville, "What is Native Structured Storage?"
  15. ^ File Compression and Decompression. MSDN Platform SDK: File Systems. Retrieved on 2005-08-18. Year 2005 ( MMV) was a Common year starting on Saturday (link displays full calendar of the Gregorian calendar. Events 293 BC - The oldest known Roman temple to Venus is founded starting the institution of Vinalia Rustica.
  16. ^ "Best practices for NTFS compression in Windows. " Microsoft Knowledge Base. Retrieved on 2005-08-18. Year 2005 ( MMV) was a Common year starting on Saturday (link displays full calendar of the Gregorian calendar. Events 293 BC - The oldest known Roman temple to Venus is founded starting the institution of Vinalia Rustica.
  17. ^ Daily, Sean (January 1998). Optimizing Disks. IDG books. Retrieved on 2007-12-17. Year 2007 ( MMVII) was a Common year starting on Monday of the Gregorian calendar in the 21st century. Events 546 - Gothic War (535–554: The Ostrogoths of King Totila
  18. ^ Single Instance Storage in Windows 2000 (PDF). Microsoft Research and Balder Technology Group. Microsoft Research (MSR is a division of Microsoft created in 1991 for researching various Computer science topics and issues
  19. ^ How EFS Works, Microsoft Windows 2000 Resource Kit
  20. ^ Transactional NTFS. MSDN. The Microsoft Developer Network ( MSDN) is the portion of Microsoft responsible for managing the firm's relationship with developers hardware developers interested Retrieved on 2007-02-02. Year 2007 ( MMVII) was a Common year starting on Monday of the Gregorian calendar in the 21st century. Events 962 - Translatio imperii: Pope John XII crowns Otto I Holy Roman Emperor, the first Holy Roman Emperor
  21. ^ "ntfsmount wiki page on linux-ntfs.org"
  22. ^ cfsbloggers (July 14, 2006). How restore points and other recovery features in Windows Vista are affected when dual-booting with Windows XP. The Filing Cabinet. Retrieved on 2007-03-21. Year 2007 ( MMVII) was a Common year starting on Monday of the Gregorian calendar in the 21st century. Events 630 - Byzantine emperor Heraclius restores the True Cross to Jerusalem.
  23. ^ How to Convert FAT Disks to NTFS. Microsoft Corporation (2001-10-25). Year 2001 ( MMI) was a Common year starting on Monday according to the Gregorian calendar. Events 1147 - The Portuguese, under Afonso I, and Crusaders from England and Flanders conquer Lisbon after a Retrieved on 2007-08-27. Year 2007 ( MMVII) was a Common year starting on Monday of the Gregorian calendar in the 21st century. Events 479 BC - Greco-Persian Wars: Persian forces led by Mardonius are routed by Pausanias, the Spartan
  24. ^ Working Around Windows Vista's "Shrink Volume" Inadequacy Problems
  25. ^ "Beating the Daylight Savings Time bug and getting correct file modification times" The Code Project
  26. ^ "Microsoft TechNet Resource Kit"
  27. ^ Mark Russinovich (November 2000). Inside Win2K NTFS, Part 1: New features improve efficiency, optimize disk utilization, and enable developers to add functionality. Windows 2000 Magazine. Microsoft. Retrieved on 2008-01-14. 2008 ( MMVIII) is the current year in accordance with the Gregorian calendar, a Leap year that started on Tuesday of the Common Events 1129 - Formal approval of the Order of the Templar at the Council of Troyes.
  28. ^ a b c More precisely, 32767 resp. 255 UTF-16 code words. In Computing, UTF-16 (16- Bit Unicode Transformation Format is a variable-length Character encoding for Unicode, capable of encoding Some rare/unusual Unicode characters require two such words.

See also

External links

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