Windows File Systems

A file system is used to organise files into directories, so that each file has a start point and an end point to segregate the data. A file system also organises files, so they can be stored and retrieved. Windows supports three native file systens, FAT, NTFS and ReFS

FAT16 and FAT32

FAT (File Allocation Table) is the file system that has been around since MS-DOS days. Bill Gates supposedly created the original FAT system in 1976, in a hotel room in Albuquerque. The original FAT, or FAT16 system supported volumes up to a maximum size of 4 GB. The FAT32 file system supports volumes up to 32GB and exFAT or extended FAT supports bigger volumes. While FAT is over 40 years old, it is still supported by Windows 10. If you insert a USB drive, then right click on it in Windows Explorer and check out 'Properties' you will probably see that the file system is FAT32. Most USB drives are formatted as FAT32 or exFAT, because FAT is supported by so many devices.

The FAT16 file system supports a maximum of 65,524 clusters per volume. FAT32 volumes must have a minimum of 65,527 clusters on a 32-GB volume, which is the largest FAT32 volume that Windows Server 2003 can format.

Volume Size FAT16 Cluster Size FAT32 Cluster Size
7 MB - 16 MB 2 KB Not supported
17 MB - 32 MB 512 bytes Not supported
33 MB - 64 MB 1 KB 512 bytes
65 MB - 128 MB 2 KB 1 KB
129 MB - 256 MB 4 KB 2 KB
257 MB - 512 MB 8 KB 4 KB
513 MB - 1,024 MB 16 KB 4 KB
1,025 MB - 2 GB 32 KB 4 KB
2 GB - 4 GB 64 KB 4 KB
4 GB - 8 GB Not supported 4 KB
8 GB - 16 GB Not supported 8 KB
16 GB - 32 GB Not supported 16 KB
32 GB - 2 terabytes Not supported Not supported


NTFS was introduced in the Windows NT operating system. Its advantages and disadvantages are discussed in the NTFS page. NTFS is the default Windows file system and is the only one that Windows will boot from. If right click on your boot drive, usually c:, in Windows Explorer and check out 'Properties' you will see that the file system is NTFS.


ReFS was introduced with Windows Server 2012. Its advantages and disadvantages are discussed in the ReFS page. Microsoft has a statement of intent to make ReFS the default file system in the future and it is fully supported by Windows 10, but not for boot drives.

Other file systems

Others ways exist to manage and access data, data that is held on CDs, DVDs or Network drives and they are mentioned below. Some of these are not exactly file systems, but are still valid ways to access and organise data.


DFS (Distributed File Sharing) was introduced in Windows NT, and then developed further right up to Windows 2016. It is a Windows Server concept, rather than stand alone PCs, which allows you to set up shared folders deployed on different servers into one or more logically structured namespaces. The idea behind DFS is to hide the location of a file or directory from the user, so that if a file or disk moves around between servers then the user is unaware of the details. This is all discussed in the DFS page


CIFS is an open system which lets groups of users to work together and share documents across the Internet. It is discussed in the CIFS page.

Compact Disk File System

The Compact Disk File System (CDFS) replaced the MS-DOS MSCDEX utility. It is used to read data from CD-ROM devices and is supported right up to Windows 10.

Life File System

The Life File System, formerly knowd as Universal Disk Format (UDF) in turn replaced CDFS. The Optical Storage Technology Association (OSTA) defined the UDF file system to work with CD, DVD and Magneto Optical storage. It is supported for Windows releases right up to Windows 10.

Offline Files

Offline Files was developed by IntelliMirror, and was introduced to Windows 2000. It is intended for mobile users who sometimes log into a network, and sometimes work standalone, and allows them to access locally cached versions of networked files, if they are working stand alone. They can also use locally cached versions of files when they are logged into the network, which can greatly improve network performance. Newer applications like OneDrive or DropBox will make this application less relevant in future.

Windows uses the Synchronisation Manager feature to keep local and remote files in step. Three Synchronisation options are available:

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