Open a Terminal, change the current directory to the directory containing
the "ReactOS.vmdk" file and execute the following command:
qemu -m 128 -hda ReactOS.vmdk
You can improve the speed of the virtual machine by installing the appropriate
Kqemu package for your system.
If you want to access and modify files of the virtual hard disk, you have to
convert it to the "raw" format.
To convert it, execute the following commands in the directory containing the
qemu-img convert ReactOS.vmdk -O raw ReactOS.hd
Beware that this takes 2 GB of hard disk space, since a raw hard disk image
is not growable.
Now you can easily mount the image with the following command:
mount -oloop,offset=32256 -t vfat ReactOS.hd /mnt/vhd
In this case, I assume that you want to mount the hard disk image to /mnt/vhd.
Otherwise modify the command line accordingly.
After you unmounted the changed hard disk, you can boot it by executing the
qemu -m 128 -hda ReactOS.hd
And now i don't know how to unmount it. Any help would be appreciated