Re: Write to DVD-RAM

On 7/24/19 10:19 PM, Zhi-Qiang Lei wrote:
> Hi, I'm trying to encrypt a DVD-RAM before putting some files onto it on my OpenBSD 6.5 desktop. But neither dd nor disklabel seems able to work on the drive. Did I miss something?
>
> $ dmesg | grep cd
> cd0 at scsibus3 targ 1 lun 0: <HL-DT-ST, BD-RE BU40N, FR07> ATAPI 5/cdrom removable serial.13fd3940302020202020
> cd0 at scsibus3 targ 1 lun 0: <HL-DT-ST, BD-RE BU40N, FR07> ATAPI 5/cdrom removable serial.13fd3940302020202020
>
> $ doas dd if=/dev/urandom of=/dev/rcd0c bs=1k
> dd: /dev/rcd0c: Invalid argument
> 1+0 records in
> 0+0 records out
> 0 bytes transferred in 0.000 secs (0 bytes/sec)
>
> $ doas disklabel -E cd0
> cd0> a
> partition: [a]
> offset: [0]
> size: [2236704]
> FS type: [4.2BSD]
> cd0> w
> cd0> p
> OpenBSD area: 0-2236704; size: 2236704; free: 0
> # size offset fstype [fsize bsize cpg]
> a: 2236704 0 4.2BSD 2048 16384 1
> c: 2236704 0 unused
> cd0> q
> No label changes.
>
> The same drive can be formatted and used on Mac OS X.
>
> Thanks and best regards,
> Siegfried
>
Did you try 2K blocks? The low level of CDROM only works that way.