mindstorm:~# mkdir /tmp/initrd ; cd /tmp/initrd ; zcat /boot/initrd.img-$(uname -r) | cpio -i
24052 blocks

mindstorm:/tmp/initrd# grep udev /tmp/initrd/init
# Note that this only becomes /dev on the real filesystem if udev's scripts
if [ -e /etc/udev/udev.conf ]; then
        . /etc/udev/udev.conf
mount -t tmpfs -o size=$tmpfs_size,mode=0755 udev /dev