read only system

etc/fstab

@@ -1,4 +1,5 @@
-/dev/mmcblk0p1 /boot vfat defaults 0 2
+/dev/mmcblk0p1	/boot					vfat 	ro															0 0
-/dev/mmcblk0p2 / ext4 errors=remount-ro,noatime,nodiratime,commit=120 0 1
+/dev/mmcblk0p2	/							ext4	noatime,nodiratime,ro						0 0
-/dev/sda	/media/floppy vfat noauto
+/dev/sda				/media/floppy	vfat	noauto
-tmpfs /tmp tmpfs defaults,nodev,nosuid 0 0
+tmpfs						/tmp					tmpfs	defaults,noatime,nodev,nosuid 	0 0
+unionfs-fuse#/tmp=rw:/ro/var=ro	/var	fuse	cow,allow_other,nonempty