Re: NTFS partitions show up as OS/2 partitions.

Phil Brutsche (
Wed, 2 Dec 1998 16:29:42 -0600 (CST)

On Wed, 2 Dec 1998, Jesper Juhl wrote:

> Hi people,
> I recently tore down a Windows NT 4.0 server that used NTFS on two
> partitions. When I ran (Linux) fdisk, I noticed that both partitions
> showed up as OS/2 HPFS partitions. The machine has never had OS/2
> installed on it!

In the partition record on PCs there's a field (8 bytes) that "tells" what
kind of file system the partition contains. Many OSs[1] would read these
fields to tell what partitions it could use - that's why MS-DOS ignores
partitions that aren't marked as one of 0x04 (a FAT16 filesystem <32 MB),
0x05 (a FAT16 system used on extended partitions), and 0x06 (FAT16
filesystems > 32MB). Win9x/NT, of course, expand that list.

In any case, OS/2 HPFS uses the ID# 0x07 in the partition record. For
some reason, Microsoft chose to use that same ID# for NTFS partitions
(according to my list[2], at least).

[1] - Linux isn't one of those - I've had Linux happily mount ext2 file
systems that were in partitions marked as FAT16 (0x06).
[2] - For reference, that list is available at

Phil Brutsche

"Be of stout heart, Number One. We've handled the Borg. We can
certainly handle Admiral Jellico." - Jean-Luc Picard

Help stop spam! Visit

To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to
Please read the FAQ at