# Do you need to use SCSI for CDRW?

## butters

I have a CDRW drive on hdd (and a DVD drive on hdc).  Do I need to enable SCSI support in the kernel to get the CDRW drive to work?  What else do I need to do?

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## syme

I assume the DVD drive uses IDE. In that case, add the following to your grub menu.lst file entry after kernel=(I think): hdd=ide-scsi hdc=ide-scsi

Disable IDE CD-ROM support in the kernel, enable general SCSI, SCSI CD-ROM support, and SCSI emulation, and you should be set. Then just run cdrecord -scanbus after the reboot to see what SCSI bus the computer put the CD writer on.

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## akhkharu99

yeah, i think syme is correct here. i know that i could not get my cdrw working unless i had scsi emulation on. although, i did not need to put anything into my menu.lst file.

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## nitro322

there's a section in the installation guide, in the kernel compile section, that tells you exactly what you need to do to enable support.  In addition to enabling support, be sure you add the lisnes it tells you to to your /etc/modules.autoload file (assuming you compile them as modules).

And by the way, disabling IDE support isn't necessary.  I have a very similar setup to yours (DVD on hdc and CD-RW on hdd), and I'll I do is pass hdd=ide-scsi to the kernel; I let my DVD-ROM drive be detected and used and regular IDE.  Hope this helps.

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## Malakin

It's the norm for an OS to use a scsi layer when dealing with an ide cd burner, that's what aspi drivers are for in windows for example.

If you remove ide cdrom support from the kernel then you don't need to use this stuff - hdd=ide-scsi. Otherwise it defaults to using ide cdrom support insted of scsi emulation.

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## unexist

of course it's the norm, because ide is a smaller version, with fewer features, of the original scsi.

actually i wonder how many threads with this topic are created.

i always remove the ide support from my kernel. i have two ide devices, 1x dvd and 1x cdrw, bot work fine with the scsi emulation and i've never added anything (hd*=ide-scsi) to the config of my bootloader.

sometimes you have to edit the config of your devfs.

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## eric.cheminot

 *Quote:*   

> i always remove the ide support from my kernel. i have two ide devices, 1x dvd and 1x cdrw, bot work fine with the scsi emulation and i've never added anything (hd*=ide-scsi) to the config of my bootloader. 

 

And how do you enable DMA for your DVD? (that is without hdparm)

-ec

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## LibraMark

If I remember correctly...

You can still use hdparm with scsi emulation.  Remember the drive is still being run by the udma chipset, even with scsi emulation.  Just do the normal #hdparm -d1 /dev/hdx (x being a for primary master, b primary slave, c secondary master, d secondary slave.)

Good luck!

Mark.

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## eric.cheminot

OK. But the problem is that /dev/hdx no longer exists when device is used by ide-scsi module... And hdparm refuses to work when i pass the scsi device. Do you know how to have the ide /dev/hdx entry (i'm using devfs)?

Thanks,

-ec

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## ebichu

 *eric.cheminot wrote:*   

> OK. But the problem is that /dev/hdx no longer exists when device is used by ide-scsi module... And hdparm refuses to work when i pass the scsi device. Do you know how to have the ide /dev/hdx entry (i'm using devfs)?

 

Do the /dev/ide/hostW/busX/targetY/lunZ/disc entries still work when using ide-scsi?

Assuming the mobo's built-in IDE controller is host0, then hdc would be /dev/ide/host0/bus1/target0/lun0/disc.

bus0 is the primary, bus1 is the secondary, target0 is the master and target1 is the slave.

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## True

I think the best solution is to use scsi emulation for the cdrw by passing the ide-scsi parameter via lilo. If you compile in ide-cdrom support as well then you can still enable dma for the dvd (otherwise dvd playback becomes awful). From what I see devfs wont create /dev/hd* entries for the cd/dvd without ide-cdrom support sompiled into the kernel. I beleive it is possible to do a mknod and create entries that you can hdparm. You then need to save the changes to devfs (not sure how that's done yet).

So I think you should compile in scsi support AND ide-cdrom support.

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