Re: [Re: [gentoo-dev] CD-RW devfs]

[Hendrik Visage]

On Mon, Oct 22, 2001 at 12:36:04PM +0100, Viktor Lakics wrote:
> Dear Hendrik,
>
> NOw I am confused. Do I need to have SCSI cdrom support in the kernel? I only
> have ide-scsi, scsi generic and ide-cd compiled as modules. I thought I only
> need SCSI cdrom support if I have a REAL scsi device...
>
> What is EXACTLY the minimum set of IDE and scsi option then what I need
> in the kernel in ordrt to use my cdrw to write and to use it as a cdrom as
> well (meaning mounting CDs and reading them)?!

For CD-RW usage (With stuff like cdrecord and friends), and accessing the
CDROM, you'll need
1) sg or pg (sg for SCSI, and pg for parallel port) for the raw communication
 to the CD-RW that cdrecord needs. These are the "Generic" devices.
2) sr_mod or pcd (sr_mod for SCSI, pcd for parallel port)
 as well as the "standard" cdrom etc. for acessing it as a CDROM device.

sr_mod & sg is under the SCSI config in the kernel, while pg & pcd are
somewhere under the parallel port stuff.

However, you have a IDE CD-RW:
Now the IDE (Actually ATAPI) CD-RWs are making use of a SCSI-over-IDE 
encapsulation. Thus the need for ide-scsi. You'll notice that when you
install the Adaptec/Nero etc. software on Windows, that they also installs a
SCSI (aspi I think) layer for comms to the CDRW.

Now the config at boot time:
 hdc=ide-scsi (I guess, machine @home :()

This tells the IDE/ATAPI layer to NOT initialize this drive in the IDE
chain for things, but that it'll be handled as a SCSI device.

Thus the need for modprobe ide-scsi to load the SCSI-over-IDE modules.
Then you'll have to modprobe sg for cdrecord to work, and lastly
modprobe sr_mod for this faked-SCSI CDROM (on the IDE/ATAPI bus).

Hope this clears it, as I just wished the ATAPI/IDE/ATA standards died a
silent/quiet/quick/horrific/long-forgotten death ages ago, so that we could
all be using SCSI with it zillions of NICE(tm) features like tag-command-queues
etc. etc. etc.

GReetz
HEndrik


>
>
> Appreciate you answer...
>
> Viktor
>
> Hendrik Visage <hvisage@×××××××××××.za> wrote:
> > On Mon, Oct 22, 2001 at 07:04:32AM +0100, Viktor Lakics wrote:
> > > Hi All,
> > >
> > > This is probably a user list question, I fighted it but I am running out
> of
> > > ideas.  I
> > > compiled IDE cdrom support as module, and ide-scsi as module in the
> kernel. I
> > >
> > > have hdb=ide-scsi with grub.
> > >
> > > My modules are not loaded automatically, devfs is not generating cdroms
> nor
> > > scsi
> > > device (scsi dir is there, but empty).
> > >
> > > 1. How can I get module autoloading? (module.autoload does NOT work : no
> > > matter what I put there. modules are not loaded). I do not have for some
> > > reason
> > > modeles.conf in etc as well)
> > >
> > > 2. Even if I do modprobe ide-scsi, ide-cd, cdrom, although the respective
> >
> > The order should be modprobe ide-scsi, sr_mod
> > YOu HAVE compiled in SCSI CDROM support???
> >
> > > modules
> > > are there, inserted, I cannot mount my cdrom. I could burn a CD, because
> the
> > > scsi
> > > generic driver is there (cdroms still not gnerated though), but when I try
> to
> > > mount
> > > a cd like:
> > >
> > > mount -t iso9660 /dev/sg0 /mnt/cdrom
> > >
> > > I get sg0 is not a block device.  Now /dev/scd0 is not there in devfs, I
> tried
> > >
> > > symlink as well, no success at all...
> > >
> > > Fresh rc6-9 tbz2 install...
> > >
> > >
> > > Thanks for any ideas...
> > >
> > > Viktor
> > >
> > >
> > >
> > >
> > > ----Viktor Lakics----
> > >
> > > Through the Internet:
> > >
> > >   lakicsv@×××.net
> > >
> > >
> > > ____________________________________________________________________
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> > >
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> >
> > --
> > ------------------------
> > Hendrik Visage
> > hvisage@×××××××××××.za
> >
> > _______________________________________________
> > gentoo-dev mailing list
> > gentoo-dev@××××××××××.org
> > http://cvs.gentoo.org/mailman/listinfo/gentoo-dev
>
>
> ----Viktor Lakics----
>
> Through the Internet:
>
>   lakicsv@×××.net
>
>
> ____________________________________________________________________
> Get free e-mail and a permanent address at http://www.amexmail.com/?A=1
>
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-- 
------------------------
Hendrik Visage
hvisage@×××××××××××.za