source: postlfs/config/bootdisk.xml@ e1100da

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<sect1 id="postlfs-config-bootdisk" xreflabel="Creating a Custom Boot Device">
  <?dbhtml filename="bootdisk.html"?>

  <sect1info>
    <othername>$LastChangedBy$</othername>
    <date>$Date$</date>
  </sect1info>

  <title>Creating a Custom Boot Device</title>

  <sect2>
    <title>Decent Rescue Boot Device Needs</title>

    <para>This section is really about creating a <emphasis>rescue</emphasis>
    device.  As the name <emphasis>rescue</emphasis> implies, the host
    system has a problem, often lost partition information or corrupted file
    systems, that prevents it from booting and/or operating normally.  For
    this reason, you <emphasis>must not</emphasis> depend on resources from
    the host being "rescued".  To presume that any given partition or hard
    drive <emphasis>will</emphasis> be available is a risky presumption.</para>

    <para>In a modern system, there are many devices that can be
    used as a rescue device: floppy, cdrom, usb drive, or even a network card.
    Which one you use depends on your hardware and your BIOS.  In the past,
    a rescue device was thought to be a floppy disk.  Today, many
    systems do not even have a floppy drive.</para>

    <para>Building a complete rescue device is a challenging task.  In many
    ways, it is equivalent to building an entire LFS system.
    In addition, it would be a repetition of information already available.
    For these reasons, the procedures for creating a rescue device image are not
    presented here.</para>

  </sect2>

  <sect2>
    <title>Creating a Rescue Floppy</title>

    <para>The software of today's systems has grown large.  Linux 2.6 no longer
    supports booting directly from a floppy.  In spite of this, there are solutions
    available using older versions of Linux.  One of the best is Tom's Root/Boot
    Disk available at <ulink url='http://www.toms.net/rb/'/>.  This will provide a
    minimal Linux system on a single floppy disk and provides the ability to
    customize the contents of your disk if necessary.</para>

  </sect2>

  <sect2>
    <title>Creating a Bootable CD-ROM</title>

    <para>There are several sources that can be used for a rescue CD-ROM.
    Just about any commercial distribution's installation CD-ROMs or
    DVDs will work.  These include RedHat, Ubuntu, and SuSE.  One
    very popular option is Knoppix.</para>

    <para>Also, the LFS Community has developed its own LiveCD available at
    <ulink url='http://www.&lfs-domainname;/livecd/'/>.  This LiveCD, is no
    longer capable of building an entire LFS/BLFS system, but is still a
    good rescue CD-ROM.  If you download the
<!--    ISO image, use <xref linkend="xorriso"/> to copy the image to a-->
    ISO image, use <ulink url="&blfs-book;multimedia/libisoburn.html">xorriso</ulink> 
    to copy the image to a CD-ROM.</para>

    <para>The instructions for using GRUB2 to make a custom rescue CD-ROM are
    also available in <ulink
    url='http://www.&lfs-domainname;/lfs/view/stable/chapter08/grub.html'>LFS
    Chapter 8</ulink>.</para>

  </sect2>

  <sect2>
    <title>Creating a Bootable USB Drive</title>

    <para>A USB pen drive, sometimes called a thumb drive, is recognized by Linux as
    a SCSI device.  Using one of these devices as a rescue device has the advantage
    that it is usually large enough to hold more than a minimal boot image.  You
    can save critical data to the drive as well as use it to diagnose and recover
    a damaged system.  Booting such a drive requires BIOS support, but building the
    system consists of formatting the drive, adding <application>GRUB</application>
    as well as the Linux kernel and supporting files.</para>

    <para>Creating a bootable USB drive from a downloaded iso file is
    relatively simple. For example, if the iso file is some-rescue.iso and when
    inserting a usb drive into the system the drive is recognized as /dev/sdg,
    the file can be copied to the drive (as the root user) with:</para>

<screen><userinput>dd of=/dev/sdg bs=8M status=progress oflag=direct if=some-rescue.iso</userinput></screen>

    <para condition="html" role="usernotes">User Notes:
    <ulink url='&blfs-wiki;/CreatingaCustomBootDevice'/></para>

  </sect2>
</sect1>