Subject: Re: How to use CR-Writer?
To: Herb Peyerl <>
From: Manuel BOUYER <>
List: current-users
Date: 01/23/1997 17:14:41
On Jan 23, Herb Peyerl wrote
> FreeBSD have a worm device that does CDR... I've not looked at what it is
> or what it looks like... I also know they have some sort of faked-out rtprio()
> call that supposedly helps the CDR get a distinct amount of attention.

Just looked at it ... Well, it makes scsi commands in the kernel,
depending on the model of drive. I don't think this is a good idea, when
we know how a CD-R migth differ from another (even from the same
manufacturer: I have 2 different ricoh drives, wich needs 2 different
commands set). Perhaps one day there will be a scsi spec for CD-R, 
that constructor will conform to ...
But for now, I think that the only way to support different drive models
is to have different programs wich sends raw scsi commands (it is how
gear and other ms-windows programs works). For example, as designed, the
FreeBSD worm driver can't support the ricoh (the 1x, old one) as it
can't write CD with the write_big command, it uses a private command,
to which I had to pass 64k data block to have enouth bandwidth on the scsi bus.
How do you pass a 64k data block with write(2) ?

Manuel Bouyer, MASI, Universite Paris VI.