<?xml version='1.0' encoding='UTF-8'?>
<!DOCTYPE topic PUBLIC "-//OASIS//DTD DITA Topic//EN" "topic.dtd">
<topic xml:lang="en-us" id="ts_linux-host-ide-messages">
  <title>Strange Guest IDE Error Messages When Writing to CD or DVD</title>
  
  <body>
    <p>
        If the experimental CD or DVD writer support is enabled with an
        incorrect host or guest configuration, it is possible that any
        attempt to access the CD or DVD writer fails and simply results
        in guest kernel error messages for Linux guests or application
        error messages for Windows guests. <ph conkeyref="vbox-conkeyref-phrases/product-name"/> performs the
        usual consistency checks when a VM is powered up. In particular,
        it aborts with an error message if the device for the CD or DVD
        writer is not writable by the user starting the VM. But
        <ph conkeyref="vbox-conkeyref-phrases/product-name"/> cannot detect all misconfigurations. The
        necessary host and guest OS configuration is not specific for
        <ph conkeyref="vbox-conkeyref-phrases/product-name"/>, but a few frequent problems are listed here
        which occurred in connection with <ph conkeyref="vbox-conkeyref-phrases/product-name"/>.
      </p>
    <p>
        Special care must be taken to use the correct device. The
        configured host CD or DVD device file name, in most cases
        <filepath>/dev/cdrom</filepath>, must point to the device that
        allows writing to the CD or DVD unit. For CD or DVD writer units
        connected to a SCSI controller or to a IDE controller that
        interfaces to the Linux SCSI subsystem, common for some SATA
        controllers, this must refer to the SCSI device node, such as
        <filepath>/dev/scd0</filepath>. Even for IDE CD or DVD writer
        units this must refer to the appropriate SCSI CD-ROM device
        node, such as <filepath>/dev/scd0</filepath>, if the
        <userinput>ide-scsi</userinput> kernel module is loaded. This module
        is required for CD or DVD writer support with some early 2.6
        kernels. Many Linux distributions load this module whenever a CD
        or DVD writer is detected in the system, even if the kernel
        would support CD or DVD writers without the module.
        <ph conkeyref="vbox-conkeyref-phrases/product-name"/> supports the use of IDE device files, such as
        <filepath>/dev/hdc</filepath>, provided the kernel supports this
        and the <userinput>ide-scsi</userinput> module is not loaded.
      </p>
    <p>
        Similar rules, except that within the guest the CD or DVD writer
        is always an IDE device, apply to the guest configuration. Since
        this setup is very common, it is likely that the default
        configuration of the guest works as expected.
      </p>
  </body>
  
</topic>
