newfs and DVD-RAM

Anybody know how to put a filesystem on to a DVD-RAM under
NetBSD-2.0_BETA/i386? It's a fine 2048 byte per sector block device, and
I can disklabel it, but newfs doesn't seem to like it.

dev1 # disklabel cd0
disklabel: Can't read master boot record 0: Invalid argument
# /dev/rcd0d:
type: ATAPI
disk: dvdram
label: dvdram
flags: removable
bytes/sector: 2048
sectors/track: 100
tracks/cylinder: 1
sectors/cylinder: 100
cylinders: 22368
total sectors: 2236704
rpm: 300
interleave: 1
trackskew: 0
cylinderskew: 0
headswitch: 0           # microseconds
track-to-track seek: 0  # microseconds
drivedata: 0

4 partitions:
#        size    offset     fstype [fsize bsize cpg/sgs]
 a:   2236700         0     4.2BSD   2048 16384     0  # (Cyl.      0 -  22366)
 d:   2236700         0     unused      0     0        # (Cyl.      0 -  22366)


dev1 # newfs -S 2048 /dev/rcd0a
/dev/rcd0a: 4368.6MB (2236700 sectors) block size 16384, fragment size 2048
        using 24 cylinder groups of 182.03MB, 11650 blks, 22912 inodes.
wtfs: write error for sector 2236699: Invalid argument

I do seem to be able to write the block:

dev1 # dd if=/dev/zero of=/dev/rcd0a bs=2048 skip=2236699 count=1
1+0 records in
1+0 records out
2048 bytes transferred in 0.002 secs (1024000 bytes/sec)

cjs
-- 
Curt Sampson  <[email protected]>   +81 90 7737 2974   http://www.NetBSD.org
    Don't you know, in this new Dark Age, we're all light.  --XTC