CD-Writer Setup



This guide describes setting up a CD-Writer on Linux. The definitive guide is the CD-Writing HOWTO . This page is for those anxious to get started quickly.

I set up my first CD-Writer about 4 years ago. A few things have changed since then, but the basic principles are the same and I've never had need to change my setup. Below, I'll describe how I do things. Others may do it a little differently, and that's fine.


What We're Going To Do

  • We're going to create a setup where you always access your CD-ROM/CDRW drives as IDE drives and only switch to SCSI when we need to write CDs.
  • There are ways around this (eg. passing hdc=ide-scsi on the command line where hdc is your CDRW drive) but those won't be covered here.
  • Both your IDE drivers and your Generic SCSI drivers will be compiled as modules.

What You Need

  • An IDE-ATAPI CD-Writer (This guide does not cover SCSI. Actually, SCSI is a lot easier)
  • Generic SCSI support in your kernel. This lets you send SCSI commands to your CD-Writer. Things will not work without this. It's unlikely that your kernel has this compiled in by default. If it doesn't, then you'll need to know how to compile a kernel. The Kernel HOWTO covers this. This guide assumes you don't have generic SCSI support.
  • The cdrecord and mkisofsprograms for creating CD data Images and writing them to disk. Most distributions come with these programs nowadays. If you don't have them, search for them on freshmeat.

Setting Up The Drive

  • First, you need to enable generic SCSI support in the kernel. Switch to your kernel source directory (usually /usr/src/linux) and do a "make menuconfig" or a "make xconfig"
  • Go to the IDE/ATA/MFM/RLL support menu and then the IDE, ATA and ATAPI Block devices submenu
  • Compile IDE/ATAPI CDROM Support and SCSI Emulation Support as modules
  • Next, from the main menu, go to the SCSI support menu and compile SCSI  support into the kernel. In the same menu, compile SCSI CDROM support  and SCSI generic support as modules
  • Save your configuration, do a make bzImage, make modules, make install and make modules_install and restart your machine with the new kernel
  • The script load_scsi below removes IDE CDROM support from your kernel and loads scsi support. The unload_scsiscript removes scsi support. The IDE CDROM drivers are used by default when you attempt to access the CDROM drive. Make these scripts executable and  put them somewhere in your path

load_scsi script
#!/bin/sh

#script to load scsi modules into kernel

#make these variables point to the mount points of your cdrom/cdrw devices
mount_point1="/mnt/cdrom"
mount_point2="/mnt/cdrom2"
mount_point3="/mnt/cdrom3"

#no need to edit anything below this point

if [ ! "$mount_point1" = "" ];
then
 umount ${mount_point1}
fi

if [ ! "$mount_point2" = "" ];
then
 umount ${mount_point2}
fi

if [ ! "$mount_point3" = "" ];
then
 umount ${mount_point3}
fi

#remove ide cdrom support
rmmod ide-cd

#enable scsi support
modprobe ide-scsi
modprobe sg
modprobe sr_mod


unload_scsi script
#!/bin/sh

#script to remove scsi support from the kernel

rmmod ide-scsi
rmmod sg
rmmod sr_mod


  • Edit the load_scsi script and set the mount_point1, mount_point2 and mount_point3 variables to point to where you mount your cdrom/cdrw drives
  • Once the scripts are in your path, to enable SCSI support in your kernel and write CDs, just type load_scsi as root
  • You can verify that your CD writer is working by typing cdrecord -scanbus. If you see your CD-Writer listed as one of the recognized drives, everything's OK. The output I receive after running load_scsi is shown below as an example:
Cdrecord 1.11a24 (i686-pc-linux-gnu) Copyright (C) 1995-2002 Jörg Schilling
Linux sg driver version: 3.1.24
Using libscg version 'schily-0.6'
scsibus0:
        0,0,0     0) 'HP      ' 'CD-Writer+ 8100 ' '1.0g' Removable CD-ROM
cdrecord: Warning: controller returns wrong size for CD capabilities page.
        0,1,0     1) 'SONY    ' 'CDU4811         ' 'PY09' Removable CD-ROM
        0,2,0     2) *
        0,3,0     3) *
        0,4,0     4) *
        0,5,0     5) *
        0,6,0     6) *
        0,7,0     7) *

  • You're now ready to write CDs
  • If something went wrong, your output should look similar to the listing below. Have a look at the CD-Writing HOWTO for possible reasons and fixes.
Cdrecord 1.11a24 (i686-pc-linux-gnu) Copyright (C) 1995-2002 Jörg Schilling
cdrecord: No such file or directory. Cannot open '/dev/pg*'. Cannot open SCSI driver.
cdrecord: For possible targets try 'cdrecord -scanbus'. Make sure you are root.



Writing CDs
  • mkisofs is used to create a CD image
  • cdrecord is used to write the image to a blank CD (or a rewritable CD)
  • The man page for cdrecord and the mkisofs man page contain full descriptions of how to use those programs
  • cdrecord can also write audio tracks by passing it the -audio flag and possibly a few other flags as well. An alternative application used for writing CD audio data is cdrdao. 
  • A number of fancy frontends for these applications exist, and if you're using a major distribution, you most likely have all the applications including at least one frontend installed. All these programs are available at freshmeat as well.


Sample CD-Writing Commands


From the output of cdrecord -scanbus above, I see that my CD-Writer drive is identified as SCSI device 0,0,0
0,0,0     0) 'HP      ' 'CD-Writer+ 8100 ' '1.0g' Removable CD-ROM

The command below takes the contents of the /uploads directory, creates and image and pipes that image to cdrecord. This way I don't store the actual image on my hard drive and waste space. I have to check that /uploads contains less than 650MB (or 700MB if you have a better drive than me). The image is created with Rockridge extensions (-r -R), symlinks are followed (-f) and long filenames are supported (-l). The image is written at 4x (speed=4) and multiple sessions are supported (-multi)
mkisofs -v -l -f -r -R /uploads | cdrecord dev=0,0,0 speed=4 -v -multi -

The next command only creates a CD Image and stores it to the hard drive as the file ~/myimage.iso
mkisofs -v -l -f -r -R -o ~/myimage.iso /uploads

Lastly, the following command can be used to write an image (eg. a downloaded ISO image or one created with mkisofs) to disk:
cdrecord dev=0,0,0 speed=8 -v -multi some_image.iso


Enjoy!!!



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