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Date:      Thu, 10 Aug 2000 01:42:50 -0600
From:      "Kenneth D. Merry" <ken@kdm.org>
To:        Soren Schmidt <sos@freebsd.dk>
Cc:        Theo van Klaveren <t.vanklaveren@student.utwente.nl>, freebsd-hackers@FreeBSD.ORG
Subject:   Re: In-kernel ioctl calls
Message-ID:  <20000810014250.B69961@panzer.kdm.org>
In-Reply-To: <200008100648.IAA91303@freebsd.dk>; from sos@freebsd.dk on Thu, Aug 10, 2000 at 08:48:50AM %2B0200
References:  <003f01c00245$eddc2340$19e55982@student.utwente.nl> <200008100648.IAA91303@freebsd.dk>

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On Thu, Aug 10, 2000 at 08:48:50 +0200, Soren Schmidt wrote:
> It seems Theo van Klaveren wrote:
> > | Here's another idea, the ata driver can read/write 2352 sector size
> > | blocks directly, no need to use that ugly ioctl. You just have to
> > | set the right blocksize, I could provide you with a function for
> > | that, no more ioctl mess ;)
> > 
> > That would be _greatly_ appreciated! The question is, would this be
> > 'portable' to other drivers? In other words, how much trouble would it cost
> > me to get AudioFS to work with SCSI?
> 
> I dont think the SCSI/CAM system can cope with != %  512 byte blocks, so
> you are out of luck there, but then again SCSI/CAM doesnt support 
> CDIOCREADAUDIO either, so you are not worse of than now :)

True enough, the cd(4) driver uses whatever blocksize the drive returns in
response to a read capacity command.  (And that is generally either 2048 or
512 bytes.)

As for the CDIOCREADAUDIO ioctl, as I mentioned to Theo in a previous
message, there are a wide variety of methods that SCSI CDROM vendors have
used to get CDDA data off the disks.  Thus the reason I've left support for
CDDA extraction to external programs like tosha and cdda2wav. :)

Neither one of those obstacles is insurmountable, but they will make it
more difficult to support something like AudioFS with the SCSI CD driver.

Ken
-- 
Kenneth Merry
ken@kdm.org


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