求教/boot/grub/menu.lst参数的意思？

default=2
timeout=5
splashimage=(hd0,7)/grub/splash.xpm.gz
hiddenmenu
title Fedora (2.6.35.12-88.fc14.i686)
root (hd0,7)
kernel /vmlinuz-2.6.35.12-88.fc14.i686 ro root=UUID=f1ff6e66-aa3a-4743-9935-c5b894f01c62 rd_NO_LUKS rd_NO_LVM rd_NO_MD rd_NO_DM LANG=zh_CN.UTF-8 KEYTABLE=us rhgb quiet
initrd /initramfs-2.6.35.12-88.fc14.i686.img
title Fedora (2.6.35.6-45.fc14.i686)
root (hd0,7)
kernel /vmlinuz-2.6.35.6-45.fc14.i686 ro root=UUID=f1ff6e66-aa3a-4743-9935-c5b894f01c62 rd_NO_LUKS rd_NO_LVM rd_NO_MD rd_NO_DM LANG=zh_CN.UTF-8 KEYTABLE=us rhgb quiet
initrd /initramfs-2.6.35.6-45.fc14.i686.img
title win7
rootnoverify (hd0,0)
chainloader +1

求教rd_NO_LUKS rd_NO_LVM rd_NO_MD rd_NO_DM 参数什么意思？