why is /dev mounted as both ramfs and tmpfs?

  not sure why i never noticed this before, but OZ 3.5.4.2-rc2 on my
tosa shows:

# mount
/dev/mtdblock2 on / type jffs2 (rw)
/proc on /proc type proc (rw)
/sys on /sys type sysfs (rw)
ramfs on /dev type ramfs (rw)              <--
ramfs on /dev/.static/dev type ramfs (rw)  <--
tmpfs on /dev type tmpfs (rw)              <--
/dev/mtdblock3 on /home type jffs2 (rw,noatime)
tmpfs on /var type tmpfs (rw)
tmpfs on /media/ram type tmpfs (rw)
devpts on /dev/pts type devpts (rw)
usbfs on /proc/bus/usb type usbfs (rw)

  i've never seen a combination of /dev being mounted simultaneously
as both tmpfs and ramfs.  is there a pointer to an explanation of
what's happening here?  the output from df suggests that those two
mount points really just represent the same thing:

# df
...
ramfs                    10240        40     10200   0% /dev
tmpfs                    10240        40     10200   0% /dev

  so what's going on here?  it clearly works, i've just never seen
anything like this.  thanks.

rday

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