I found that the system disk of that windows xp virtual machine uses 'msdos' parttype.
So i partition another disk with 'msdos' and formated it to ntfs, and attach it again.
But no luck. the windows xp still can't recognise this parttion and i have to delete this so called 'unknow partition' and recreate it from inside windows.

On Thu, May 31, 2012 at 2:41 PM, me,apporc <appleorchard2000@gmail.com> wrote:
I use guestfs.part_disk to  partition one disk with 'mbr' and formated it to ntfs, then attach this disk to one windows xp virtual machine.
But this windows xp can't recognise that partition, it says 'uknown partition'

Why it is so, and how to solve it? May someone help me with this problem?