Windows File System Formats

Windows includes support for the following file system formats:

  • CDFS

  • UDF

  • FAT12, FAT16, and FAT32

  • exFAT

  • NTFS

Each of these formats is best suited for certain environments, as you’ll see in the following sections.


CDFS (%SystemRoot%\System32\Drivers\Cdfs.sys), or CD-ROM file system, is a read-only file system driver that supports a superset of the ISO-9660 format as well as a superset of the Joliet disk format. While the ISO-9660 format is relatively simple and has limitations such as ASCII uppercase names with a maximum length of 32 characters, Joliet is more flexible and supports Unicode names of arbitrary length. If structures for both formats are present on a disk (to offer maximum compatibility), CDFS uses the Joliet ...

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