NTFS is a file system based on security and it is a unique file system structure adopted by Windows NT. It is created on the base of file protection and directory data. Meanwhile, it can save storage resources and reduce disk usage. The widely used Windows NT 4.0 is adopting NTFS4.0 file system, and users must be deeply impressed by its advantaged system .Win 2000 adopts newer edition of NTFS file system—NTFS5.0. Its release not only allows users to operate and manage computer as conveniently and efficiently as that in Win 9X, but also makes users to enjoy the system security brought by NTFS.
The main features of NTFS 5.0 are following:
1. The size of partitions( it is called volume in dynamic disks ) that NTFS 5.0 supports is 2TB at most while the size of partitions supported by FAT 32 in Win 2000 is 32 GB at most.
2. NTFS5.0 is a resumable file system and users hardly need to operate the disk repair program. NTFS guarantees partitions consistency by using standard transaction log and recovery technology. When system failure occurs, NTFS 5.0 will automatically recover consistency of system by using journal file and checkpoint information.
3. NTFS 5.0 is in support of the compression of partitions, folders and files. Any application based on Windows can read and write compressed files in NTFS5.0 partitions without uncompressing by other program in advance. When reading and writing documents begins, files uncompress program will run automatically. And files will be compressed automatically when closed or saved.
4. NTFS5.0 adopts smaller cluster to manage disk space efficiently. In FAT32 file system of Win 2000, when partitions vary from 2GB-8GB, one cluster is 4KB; when partitions vary from 8GB-16GB, one cluster is 8KB; and, when partitions vary from 16GB-32GB, one cluster is 16KB. However, in NTFS file system of Win2000, when the partition is less than 2GB, the size of cluster is smaller than that of FAT32. When the partition is bigger than 2GB (2 GB-2TB), every cluster is 4KB. Therefore, compared with FAT32, NTFS can manage disk space more efficiently and decrease disk space waste furthest.
5. In NTFS 5.0 partitions, users can set access permission authorities of sharing resources, folders and files. It contains tow aspects: one is which group or user can access the folders, files and sharing resources and the other is what level the group or user can access. Set of access permission authorities is not only suitable for local computer users, but also suitable for network users who access files through network sharing folders. Compared with access to folders or files in FAT32 file system, it is more security in NTFS5.0. In addition, in Win 2000 adopting NTFS format, audit policy can be used to audit folders, files and active directory object.
And audit results are recorded in security log. Through the security log, the administrator can check which group or user has accessed to folders files and active directory object and what level operation they have done. So the possible illegal access to the system can be found out and corresponding methods will be taken to reduce this kind of potential safety hazard furthest. It even can encrypt every file. Maybe some users will say this function has been realized by setting permission for users in NT4.0. But the encryption file system of NTFS 5.0 is not same as that of NT4.0. It is a new feature of NTFS. It encrypts file by using a random generation key which is only controlled by the owner and administrator. Even others can login in the system, they can not read it. However, the file itself is not encrypted in NT 4.0. If the user without access permission wants to read the file, it will be realized by installing another NT in the disk. Nevertheless, files are encrypted to store in NTFS5.0. Even the user installs another Windows 2000; the decrypted key can not be obtained. So the security of encryption file system is higher.
6. NTFS file system can manage disk quota in Win 2000. Disk quota is that administrator can define the using space for users by quota limit and every user can only use disk space within the maximum quota. When disk quota is set, the disk usage of every user can be monitored and controlled. Through the monitor, the users exceeding quotas alarm threshold and quota limit can be identified and corresponding methods can be taken. The use of disk quota management makes the administrator allocate storage resources to users conveniently and reasonably. And this avoids system crash caused by disk usage space out of control, which increase the security of system.
7. NTFS also uses a "dynamic" log to record the change of files.
8. NTFS 5.0 is in support of dynamic disk. That means users can change the size of partitions online, without log out or formatting or restarting. In addition, if a partition contains important file information, the user can dynamically create mirrored image for this partition. In the process, the user can read and write documents in this partition as normal. When the mirror image is not needed, it can be canceled online.