DOS FAT12/16/32 filesystem
The limits for DOS FAT12/16/32 filesystems include:
- Filename length
- 255 characters.
- Pathname length
- 260 characters.
- File size
- 4 GB − 1; uses a 32-bit filesystem format.
- Directory size
- Depends on the type of filesystem:
- The root directory of FAT12/16 is special, in that it's pregrown and can't increase. You choose the size when you format, and is typically 512 entries. FAT32 has no such limit.
- FAT directories are limited (for DOS-compatability) to containing 64 K entries.
- For long (non-8.3) names, a single filename may need multiple entries, thus reducing the possible size of a directory.
- Filesystem size
- Depends on the FAT format:
- for FAT12, it's 4084 clusters (largest cluster is 32 KB, hence 128 MB)
- for FAT16, it's 65524 clusters (thus 2 GB)
- for FAT32, you get access to 268435444 clusters (which is 8 TB)
- Disk size
- Limited by the disk driver and io-blk.
These filesystems don't really support permissions, but they can emulate them.