Re: cd burning: kernel / userspace?

From: Wakko Warner
Date: Tue Aug 10 2004 - 17:12:21 EST


> I've followed the latest cdrecord "discussion" on the list, and I can't
> see why you have to use a userspace program which talks SCSI in order to
> burn a cd.

I agree.

> Why can't a similar method be used for DAO writing? Packet writing and
> Mount Rainer support belongs in the kernel - why not normal cd burning?
> On modern "burnproof" hardware, it should be possible to use dd to write
> your disk image to the cdrecorder device. I'm guessing that this just
> isn't as interesting, especially with userspace programs available to do
> the job.

Disclamer: I'm not a kernel hacker. Just looking at things on how they
appear to me...

I have thought about this myself. Using CDR/RW with the UDF format would be
simply packet writing. This is already supported with CDRWs.

However, I usually burn ISO instead of UDF. How should these instances be
supported:

1) DAO (ISO image burned)
2) TAO single session with or without fixation. I have burned audio disks
like this before where I would leave off the fixate option and keep burning,
each track is closed.
3) TAO multi session leaving disk open
4) TAO multi session closing disk (probably similar if not the same as 2)
5) blanking a CDRW (fast and/or slow)

Maybe something along the lines of IOCTLs that do these? Wouldn't it seem
silly to:
cdrwcontrol DAO speed=40 burnproof ....
dd if=my.iso of=/dev/scd0 (sorry, I'm a scsi guy =)

or cdrwcontrol TAO speed=40 ...
dd ..
cdrwcontrol fixate

Ok, enough rambling, I think the idea is out =)

--
Lab tests show that use of micro$oft causes cancer in lab animals
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