On 05/12/16 17:13, Samuel Sieb wrote:
On 12/05/2016 04:18 AM, Tim wrote:
> Allegedly, on or about 04 December 2016, Samuel Sieb sent:
>> I haven't tried using dd to write an optical disk. I would not expect
>> it work and it shouldn't work.
>
> I haven't, either. But I'd be inclined to think that it would. If your
> ISO file is simply an image of what is going to burnt to disc, in
> essence what will be streamed to the laser, then you shouldn't have to
> do much beyond sending the data towards the optical device.
>
> The fly in the ointment would be whether a optical burner begins burning
> when data is sent to it, or whether commands need issuing to it first
> (and it could well be that dd isn't completely dumb, nor the device
> handlers).
>
dd is "dumb" in that way, but it's possible the device driver might have
some sort of handling. But my understanding is that there's a certain
amount of device setup required which depends on which format you're
writing the data in. And I think there's some sort of redundancy info
that needs to be generated as well.
I don't really understand the wish to use dd for this. I burn dvds
from iso several times a week, using k3b in verify mode. FWIW the
growisofs command it uses is apparently:
/usr/bin/growisofs -Z /dev/sr0=/dev/fd/0 -use-the-force-luke=notray
-use-the-force-luke=tty -use-the-force-luke=4gms
-use-the-force-luke=tracksize:2240945 -use-the-force-luke=dao:2240945
-dvd-compat -speed=6 -use-the-force-luke=bufsize:32m