The last disk block FAT element includes the special code to signify the end of the file. It includes characteristics such as data recovery, multi-streaming, fault tolerance, security, extended file size and file systems, UNICODE names. NTFS maintains a journal which keeps track of the operations performed in the drive and can quickly recover the errors, shadow copies for backup, encryption, disk quota limits and hard links. It prevents unauthorised access to file contents by enforcing an encryption system named as Encryption File System which uses public key security.
The NTFS file system does not rely on the sector sizes on the different disks. It uses a concept of the clusters and cluster is a group of contiguous sectors for the disk space allocation. The cluster could contain 2 n number of sectors. A logical partition on the disk is known as volume and it utilizes a bitmap file to signify the allocated and vacant clusters in the volume.
There is also file named as bad cluster file to keep the record of unusable clusters. A volume set provides a way to exceed the capacity of the partitions which is up to 32 volumes.
Over years, few minor modifications were made on FAT16 file system so that it could handle hard disks and longer file names which originally had limitation of 8. One of the disadvantages of FAT16 is that it has a fixed number of clusters per partition which makes the hard disk bigger.
FAT16 also does not support encryption, compression or any advanced security using access to control lists. FAT32 is just an extension of FAT16 file system which provides a large number of clusters per partition.
It was first introduced with the first version of Windows NT. The latter is little more than an extension of the original FAT16 file system that provides for a much larger number of clusters per partition. As such, it offers greatly improved disk utilisation over FAT The Home edition of Windows XP allows users to keep their information private to themselves, while the Professional version supports access control and encryption of individual files and folders.
The file system is inherently more resilient than FAT, being less likely to suffer damage in the event of a system crash and it being more likely that any damage is recoverable via the chkdsk. NTFS also journalises all file changes, so as to allow the system to be rolled back to an earlier, working state in the event of some catastrophic problem rendering the system inoperable.
The smaller the cluster size, the more efficiently a disk stores information because unused space within a cluster cannot be used by other files; the more clusters supported, the larger the volumes or partitions that can be created. The table below provides a comparison of volume and default cluster sizes for the different Windows file systems still commonly in use:.
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