<P> exFAT is a proprietary and patent - protected file system with certain advantages over NTFS with regard to file system overhead . </P> <P> exFAT is not backward compatible with FAT file systems such as FAT12, FAT16 or FAT32 . The file system is supported with newer Windows systems, such as Windows Server 2003, Windows Vista, Windows 2008, Windows 7, Windows 8, and more recently, support has been added for Windows XP . </P> <P> exFAT is supported in OS X starting with version 10.6. 5 (Snow Leopard). Support in other operating systems is sparse since Microsoft has not published the specifications of the file system and implementing support for exFAT requires a license . exFAT is the only file system that is fully supported on both OS X and Windows that can hold files bigger than 4 GB . </P> <P> Prior to the introduction of VSAM, OS / 360 systems implemented an unusual hybrid file system . The system was designed to easily support removable disk packs, so the information relating to all files on one disk (volume in IBM terminology) is stored on that disk in a flat system file called the Volume Table of Contents (VTOC). The VTOC stores all metadata for the file . Later a hierarchical directory structure was imposed with the introduction of the System Catalog, which can optionally catalog files (datasets) on resident and removable volumes . The catalog only contains information to relate a dataset to a specific volume . If the user requests access to a dataset on an offline volume, and he has suitable privileges, the system will attempt to mount the required volume . Cataloged and non-cataloged datasets can still be accessed using information in the VTOC, bypassing the catalog, if the required volume id is provided to the OPEN request . Still later the VTOC was indexed to speed up access . </P>

What file systems can be used by servers