DVD-RAM on FreeBSD?

[Wilko Bulte]

Today I by coincidence found myself with DVD-RAM disk.

Given that my DVD drive ( NEC DVD_RW ND-4571A 1-01 ) should be able
to work with DVD-RAM disks my curiosity got the best of me.  Currently
running 

FreeBSD freebie.xs4all.nl 6.2-PRERELEASE FreeBSD 6.2-PRERELEASE #6: Fri Dec 22 17:16:16 CET 2006     root at freebie.xs4all.nl:/usr/src/sys/i386/compile/FREEBIE  i386

Following the handbook's suggestion at

http://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/creating-dvds.html

I tried:

-su-2.05b# dd if=/dev/zero of=/dev/acd0 count=2
dd: /dev/acd0: Invalid argument
1+0 records in
0+0 records out
0 bytes transferred in 0.002064 secs (0 bytes/sec)

I have tried different blocksizes with dd but that does not help.

From:

-su-2.05b# dvd+rw-mediainfo /dev/dvd
INQUIRY:                [_NEC    ][DVD_RW ND-4571A ][1-01]
GET [CURRENT] CONFIGURATION:
 Mounted Media:         12h, DVD-RAM
 Current Write Speed:   6.1x1385=8467KB/s
 Write Speed #0:        6.1x1385=8467KB/s
 Write Speed #1:        5.1x1385=7056KB/s
 Write Speed #2:        4.1x1385=5645KB/s
 Write Speed #3:        3.1x1385=4234KB/s
 Write Speed #4:        2.0x1385=2822KB/s
 Write Speed #5:        1.0x1385=1411KB/s
GET [CURRENT] PERFORMANCE:
 Write Performance:     3.0x1385=4155KB/s@[0 -> 2236704]
 Speed Descriptor#0:    03/2236704 R at 3.0x1385=4155KB/s W at 3.0x1385=4155KB/s
 Speed Descriptor#1:    03/2236704 R at 2.0x1385=2770KB/s W at 2.0x1385=2770KB/s
READ DVD STRUCTURE[#0h]:
 Media Book Type:       16h, DVD-RAM book [revision 6]
 Legacy lead-out at:    2314080*2KB=4739235840
READ DISC INFORMATION:
 Disc status:           other
 Number of Sessions:    1
 State of Last Session: complete
 "Next" Track:          1
 Number of Tracks:      1
READ FORMAT CAPACITIES:
 unformatted:           2295072*2048=4700307456
 00h(800):              2236704*2048=4580769792
 00h(800):              2295072*2048=4700307456
-su-2.05b# 

it appears the disk is recognised OK.

One can run dvd+rw-format on the disk without problems.

I'm probably missing something (but so is the handbook IMO ;-)
so suggestions are welcome.  Especially from people running DVD-RAM
successfully on RELENG_6

thanks,
Wilko

-- 
Wilko Bulte				wilko at FreeBSD.org