The name of the filesystem in use on this volume, if it is known.
Known values include "HPFS", "JFS", "FAT16", "FAT32", "NTFS", "UDF", "CDFS", "Linux" and "????".
Note that there is an apparent error in the current OS/2 implementation which causes partition type 0x83 (Linux native) to be reported as "????" while type 0x82 (Linux swap) is reported as "Linux".