exFAT

exFAT, short for Extended File Allocation Table, is a file system developed by Microsoft and introduced in 2006 as a solution for flash memory devices that exceed FAT32’s limits. It is optimized for high-capacity removable media such as USB flash drives and SDXC cards, providing large file and volume support while preserving cross‑platform compatibility for portable storage.

Key features include support for very large files and volumes through 64-bit file sizes and a simplified directory structure compared with NTFS. exFAT supports long file names with Unicode, multiple cluster sizes, and efficient metadata operations, making it suitable for media with rapid read/write cycles. It does not implement journaling or advanced access control lists, and file permissions are not part of the file system; reliability under sudden power loss relies on the host system’s handling of metadata writes.

Compatibility and licensing: exFAT is proprietary to Microsoft, but it has been licensed for use on a variety of devices and operating systems. Windows and macOS provide built‑in exFAT support across contemporary versions, and Linux and other systems have gained in‑kernel or user‑space implementations in recent years. For cross‑platform removable media intended for broad use, exFAT is commonly chosen over FAT32 when file sizes or drive capacities exceed FAT32 limits.

Limitations and alternatives: FAT32 remains widely compatible but imposes a 4 GB file size limit. exFAT has no practical single‑file limit, but support on older devices and in certain embedded environments may vary. In environments requiring POSIX permissions and journaling, other file systems may be more appropriate.