cdrdao (WAS Re: [CLUE-Tech] ISO images from Audio CD's?)

[Timothy C. Klein]

* David Anselmi (anselmi at americanisp.net) wrote:
> Timothy C. Klein wrote:
> [...]
> 
> >>
> >>Why?  Can't you just change out the drivers (assuming they are all 
> >>modules)?  True, you can't write to it as a CDRW and read from it as a 
> >>DVD at the same time...
> >>
> >
> >
> >Because, to simplify the job of the burning software, it only
> >understands SCSI commands.  So, as far as I know, it started with
> >cdrecord.  Only devices that have a SCSI interface can be used by
> >cdrecord.  So, if you wanted to pipe information from one CD into
> >cdrecord and right back out to another CD, cdrecord can only read from
> >a CD drive if it speaks SCSI.
> 
> No, I think you are missing my point.  ATAPI CD drives (DVD, CDRW, 
> whatever, that use an IDE controller) can be controlled by either the 
> IDE driver or the SCSI driver.  If you want to write to a CD, you have 
> to use the SCSI driver because SCSI supports features that IDE doesn't 
> (and Joerg Schilling used it in cdrecord which has little competition).

I did not realize that the writing commands are only supported in SCSI.
If so, that would explain why SCSI is required for all the burning.  And
while they an ATAPI device can be controlled by through SCSI or IDE, it
can't be switched from one to the other without a reboot, as far as I
can tell.

> If you want to read from an ATAPI drive, you can use either the IDE 
> drivers or the SCSI drivers.  If IDE works better for you, use those. 
> If your drivers are modules, it shouldn't be hard to switch them out. 
> Probably your IDE driver loads first.  Probably you have settings 
> (modules.conf) to tell it not to grab the burner.  Probably you'll have 
> to adjust that.  Once you understand it, write a script to make it easy.
> 

I know how to get my DVD controlled by the IDE controller, and how to
get my CDROM controlled by the IDE-SCSI emulator.  That is no problem.
The problem is that none of the CD ripping/burning software supports
*reading* from an IDE device as input.  They all rely on talking to the
CDROM through a SCSI interface.  So if I have my DVD drive controlled by
IDE, so that I can get DMA and such, it is useless for piping data to my
CD Burner.  Thus I can not go directly from CD to CD, I have to buffer
to the hard drive.  A minor but annoying detail.

So if SCSI is indeed required for burning, that explains why there is a
prevalence of SCSI-required burning software.  The trouble is that all
of the programs I have tried have carried that requirement to the read
side, where it does not need to be enforced.

Tim
--
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== Timothy Klein || teece at silverklein.net   ==
== ---------------------------------------- ==
== "Hello, World" 17 Errors, 31 Warnings... ==
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