Windows NT File Systems

This section contains information about the two file systems that Windows NT supports:

• File Allocation Table (FAT). The computer can access files on a FAT volume when it is running Windows NT, Windows 95, MS-DOS, or OS/2.
• Windows NT File System (NTFS). The computer must be running Windows NT to be able to access files on an NTFS volume.

The FAT file system is a simple file system originally designed for small disks and simple folder structures. The FAT file system is named for its method of organization, the file allocation table, which resides at the beginning of the volume. To protect the volume, two copies of the table are kept, in case one becomes damaged. In addition, the file allocation tables and the root folder must be stored in a fixed location so that the files needed to start the system can be correctly located.

The FAT file system works the same in Windows NT as it does in MS-DOS, Windows 3.1x, and Windows 95. In fact, you can install Windows NT on your existing FAT primary partition. When running Windows NT, you can move or copy files between FAT and NTFS volumes.

Note

You cannot use Windows NT with any compression or partitioning software that requires disk device drivers to be loaded by MS-DOS. Therefore, you cannot use MS-DOS 6.0 DoubleSpaceâ or MS-DOS 6.22 DiskSpace on a FAT primary partition or logical drive that you want to access when running Windows NT.

The Windows NT file system (NTFS) provides a combination of performance, reliability, and compatibility not found in the FAT file system. It is designed to quickly perform standard file operations such as read, write, and search — and even advanced operations such as file-system recovery — on very large hard disks.

The NTFS file system includes security features required for file servers and high-end personal computers in a corporate environment. The NTFS file system supports data access control and ownership privileges that are important for the integrity of critical data. While folders shared on a Windows NT computer are assigned particular permissions, NTFS files and folders can have permissions assigned whether they are shared or not. NTFS is the only file system on Windows NT that allows you to assign permissions to individual files. However, when you move or copy a file from an NTFS to a FAT volume, permissions and other attributes unique to the NTFS file system are lost.

You can use either or both of these file systems on a computer. Which one you choose for your computer, or for an individual volume on your computer, depends on such things as:

• How you expect to use the computer.
• The hardware platform.
• The size and number of hard disks.
• Security considerations.

For more information about file systems, especially NTFS, see Inside the Windows NT File System, by Helen Custer (Microsoft Press 1994, ISBN 1-55615-660-X), which documents the NTFS file system design.