title Install ubuntu-gnome-14.04 root (hd0,6) kernel (hd0,6)/vmlinuz boot=casper iso-scan/filename=/ubuntu-14.04.3-desktop-amd64.iso ro quiet splash locale=zh_CN.UTF-8 initrd (hd0,6)/initrd.lz
hd(0,6) is the third logical partition on the first hard disk C, D(hd(0,4)), E(hd(0,5)), F (this disk hd(0,6) )
uninstall isodevice
sudo umount -l /isodevice