NTFS
| Filesystems |
|---|
| Virtual Filesystems |
| Disk Filesystems |
| CD/DVD Filesystems |
| Network Filesystems |
| Flash Filesystems |
NTFS (New Technology File System) is Windows NT's native file system. It is not only based on HPFS, but also supports security features such as access control. Since Windows NT is entirely unicode, NTFS is a unicode filesystem, with each character (e.g. in names) being 16-bits instead of 8-bits.
About
NTFS doesn't only add security features to HPFS. In NTFS, there is a lot more built-in redundancy. For example: in HPFS, wiping out a sector in the wrong place can render the entire volume inaccessible. Support for multiple hard-links to a file (before NTFS, the only easy access was through the POSIX subsystem, but Windows 2000 (NT 5) added this to Win32 as well) was also added.
NTFS supports an arbitrary number of file forks (much like Mac OS, except Mac OS always has exactly 2 forks for each file).
HPFS decrees that a cluster is always 512 bytes long and a cluster is always one sector. For the sake of performance and compatibility with some (especially Japanese) machines, NTFS allows sectors of different sizes. It also supports clusters of more than one sector, which can be beneficial on performance.
In short, NTFS' most significant changes:
- Better and more security.
- Multiple hard-links to one file.
- An arbitrary number of forks.
- Variable cluster and sectors sizes (usually resulting in better performance).
Implementation
NTFS is probably one of the most difficult file system to deal with, especially because of the lack of hacking experience and reliable documents. A read-only stable driver can be found in the Linux source code base since kernel 2.4, while an experimental read-write driver is coming with linux 2.6.
The NTFS-3G project apparently has a read/write implementation for Linux/FreeBSD/BeOS that is currently in beta development status.