source: BOOK/boot/common/devices.xml@ d6aaa67

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<!DOCTYPE sect1 PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
  "http://www.oasis-open.org/docbook/xml/4.5/docbookx.dtd" [
  <!ENTITY % general-entities SYSTEM "../../general.ent">
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<sect1 id="ch-boot-devices">
  <?dbhtml filename="devices.html"?>

  <title>Populating /dev</title>

  <indexterm zone="ch-boot-devices">
    <primary sortas="e-/dev/*">/dev/*</primary>
  </indexterm>

  <sect2>
    <title>Creating Initial Device Nodes</title>

    <note os="a">
      <para>The commands in the remainder of the book should be run as
      the <systemitem class="username">root</systemitem> user. Check 
      that ${CLFS} is set in the 
      <systemitem class="username">root</systemitem> user&rsquo;s environment
       before proceeding.</para>
    </note>

    <para os="b">When the kernel boots the system, it requires the presence
    of a few device nodes, in particular the <filename
    class="devicefile">console</filename> and <filename
    class="devicefile">null</filename> devices. The device nodes will
    be created on the hard disk so that they are available before
    <command>udev</command> has been started, and additionally when Linux
    is started in single user mode (hence the restrictive permissions on
    <filename class="devicefile">console</filename>). Create these by running
    the following commands:</para>

<screen><userinput>mknod -m 600 ${CLFS}/dev/console c 5 1
mknod -m 666 ${CLFS}/dev/null c 1 3</userinput></screen>

    <para>Before udev starts a tmpfs filesystem is mounted over <filename class="directory">/dev</filename> and the previous entries are no-longer available. The folling command creates files that are copied over by the udev bootscript:</para>

<screen><userinput>mknod -m 600 ${CLFS}/lib/udev/devices/console c 5 1
mknod -m 666 ${CLFS}/lib/udev/devices/null c 1 3</userinput></screen>

  </sect2>

</sect1>