svn commit: r44622 - head/en_US.ISO8859-1/books/handbook/boot
Dru Lavigne
dru at FreeBSD.org
Mon Apr 21 21:29:57 UTC 2014
Author: dru
Date: Mon Apr 21 21:29:57 2014
New Revision: 44622
URL: http://svnweb.freebsd.org/changeset/doc/44622
Log:
Prep work for boot chapter.
Add missing items from what is covered in this chapter list.
Add note about GPT and EFI/UEFI.
Some shuffling of headings to improve flow.
More commits to come.
Sponsored by: iXsystems
Modified:
head/en_US.ISO8859-1/books/handbook/boot/chapter.xml
Modified: head/en_US.ISO8859-1/books/handbook/boot/chapter.xml
==============================================================================
--- head/en_US.ISO8859-1/books/handbook/boot/chapter.xml Mon Apr 21 21:16:02 2014 (r44621)
+++ head/en_US.ISO8859-1/books/handbook/boot/chapter.xml Mon Apr 21 21:29:57 2014 (r44622)
@@ -19,7 +19,7 @@
<para>The process of starting a computer and loading the operating
system is referred to as <quote>the bootstrap process</quote>,
- or simply <quote>booting</quote>. &os;'s boot process provides
+ or <quote>booting</quote>. &os;'s boot process provides
a great deal of flexibility in customizing what happens when
the system starts, including the ability to select from
different operating systems installed on the same computer,
@@ -47,18 +47,27 @@
</listitem>
<listitem>
- <para>The basics of &man.device.hints.5;.</para>
+ <para>How to configure a customized boot splash screen.</para>
+ </listitem>
+
+ <listitem>
+ <para>The basics of setting device hints.</para>
+ </listitem>
+
+ <listitem>
+ <para>How to boot into single- and multi-user mode and how to
+ properly shutdown a &os; system.</para>
</listitem>
</itemizedlist>
<note>
<para>This chapter only describes the boot process for &os;
- running on Intel x86 systems.</para>
+ running on x86 and amd64 systems.</para>
</note>
</sect1>
<sect1 xml:id="boot-introduction">
- <title>The Booting Problem</title>
+ <title>&os; Boot Process</title>
<para>Turning on a computer and starting the operating system
poses an interesting dilemma. By definition, the computer does
@@ -71,7 +80,7 @@
<para>This problem parallels one in the book
<citetitle>The Adventures of Baron Munchausen</citetitle>. A
character had fallen part way down a manhole, and pulled himself
- out by grabbing his bootstraps, and lifting. In the early days
+ out by grabbing his bootstraps and lifting. In the early days
of computing the term <firstterm>bootstrap</firstterm> was
applied to the mechanism used to load the operating system,
which has become shortened to <quote>booting</quote>.</para>
@@ -81,9 +90,9 @@
<indexterm><primary>Basic Input/Output
System</primary><see><acronym>BIOS</acronym></see></indexterm>
- <para>On x86 hardware the Basic Input/Output System
+ <para>On x86 hardware, the Basic Input/Output System
(<acronym>BIOS</acronym>) is responsible for loading the
- operating system. To do this, the <acronym>BIOS</acronym>
+ operating system. The <acronym>BIOS</acronym>
looks on the hard disk for the Master Boot Record
(<acronym>MBR</acronym>), which must be located in a specific
place on the disk. The <acronym>BIOS</acronym> has enough
@@ -91,6 +100,19 @@
assumes that the <acronym>MBR</acronym> can then carry out the
rest of the tasks involved in loading the operating system,
possibly with the help of the <acronym>BIOS</acronym>.</para>
+
+ <note>
+ <para>amd64 hardware is backward compatible as it understands
+ <acronym>BIOS</acronym> instructions. Newer hardware uses
+ a GUID Partition Table (<acronym>GPT</acronym>) instead of a
+ <acronym>MBR</acronym>. &os; can boot from a
+ <acronym>MBR</acronym> or <acronym>GPT</acronym> partition.
+ When booting from <acronym>GPT</acronym>, &os; can boot from
+ either a legacy <acronym>BIOS</acronym> or an Extensible
+ Firmware Interface (<acronym>EFI</acronym>). Work is in
+ progress to provide Unified Extensible Firmware Interface
+ (<acronym>UEFI</acronym>) support.</para>
+ </note>
<indexterm><primary>Master Boot Record
<acronym>MBR</acronym>)</primary></indexterm>
@@ -101,60 +123,50 @@
<para>The code within the <acronym>MBR</acronym> is usually
referred to as a <emphasis>boot manager</emphasis>, especially
- when it interacts with the user. In this case, the boot
+ when it interacts with the user. The boot
manager usually has more code in the first
- <emphasis>track</emphasis> of the disk or within the file
- system of some operating systems. A boot manager is sometimes
- also called a <emphasis>boot loader</emphasis>, but &os; uses
- that term for a later stage of booting. Popular boot managers
- include <application>boot0</application>, also called
- <application>Boot Easy</application>, the standard &os; boot
- manager, <application>Grub</application>,
- <application>GAG</application>, and
- <application>LILO</application>. Only
- <application>boot0</application> fits within the
- <acronym>MBR</acronym>.</para>
+ track of the disk or within the file
+ system. Examples of boot managers
+ include the standard &os; boot
+ manager <application>boot0</application>, also called
+ <application>Boot Easy</application>, and <application>Grub</application>,
+ which is used by many &linux; distributions.</para>
- <para>If only one operating system is installed, a standard PC
- <acronym>MBR</acronym> will suffice. This
+ <para>If only one operating system is installed, the
<acronym>MBR</acronym> searches for the first bootable (active)
slice on the disk, and then runs the code on that slice to load
- the remainder of the operating system. By default, the
- <acronym>MBR</acronym> installed by &man.fdisk.8; is such an
- <acronym>MBR</acronym> and is based on
- <filename>/boot/mbr</filename>.</para>
-
- <para>If multiple operating systems are present, a different boot
+ the remainder of the operating system. If multiple operating
+ systems are present, a different boot
manager can be installed which displays the list of operating
- systems so that the user can choose which one to boot from. Two
- boot managers are discussed in the next subsection.</para>
+ systems so that the user can choose which one to boot from.</para>
<para>The remainder of the &os; bootstrap system is divided into
- three stages. The first stage is run by the
- <acronym>MBR</acronym>, which knows just enough to get the
+ three stages. The first stage knows just enough to get the
computer into a specific state and run the second stage. The
second stage can do a little bit more, before running the third
stage. The third stage finishes the task of loading the
operating system. The work is split into three stages because
- PC standards put limits on the size of the programs that can be
+ the <acronym>MBR</acronym> puts limits on the size of the programs that can be
run at stages one and two. Chaining the tasks together allows
&os; to provide a more flexible loader.</para>
<indexterm><primary>kernel</primary></indexterm>
<indexterm><primary>&man.init.8;</primary></indexterm>
- <para>The kernel is then started and it begins to probe for
+ <para>The kernel is then started and begins to probe for
devices and initialize them for use. Once the kernel boot
process is finished, the kernel passes control to the user
- process &man.init.8;, which then makes sure the disks are in a
- usable state. &man.init.8; then starts the user-level resource
+ process &man.init.8;, which makes sure the disks are in a
+ usable state, starts the user-level resource
configuration which mounts file systems, sets up network cards
to communicate on the network, and starts the processes which
- have been configured to run on a &os; system at startup.</para>
- </sect1>
+ have been configured to run at startup.</para>
+
+ <para>This section describes these stages in more detail and
+ demonstrates how to interact with the &os; boot process.</para>
- <sect1 xml:id="boot-boot0">
- <title>The Boot Manager and Boot Stages</title>
+ <sect2 xml:id="boot-boot0">
+ <title>The Boot Manager</title>
<indexterm><primary>Boot Manager</primary></indexterm>
@@ -232,6 +244,7 @@ label=FreeBSD</programlisting>
run <command>/sbin/lilo -v</command> to commit the new
changes. Verify these are correct by checking the screen
messages.</para>
+ </sect2>
<sect2 xml:id="boot-boot1">
<title>Stage One and Stage Two</title>
@@ -605,6 +618,7 @@ boot:</screen>
boot flags.</para>
</note>
</sect2>
+ </sect1>
<!--
<sect2 id="boot-kernel-userconfig">
@@ -613,7 +627,7 @@ boot:</screen>
<para> </para>
</sect2> -->
- <sect2 xml:id="boot-splash">
+ <sect1 xml:id="boot-splash">
<info>
<title>Configuring Boot Time Splash Screens</title>
@@ -766,7 +780,6 @@ bitmap_name="<replaceable>/boot/splash.b
<para>For more information, refer to &man.splash.4;,
&man.loader.conf.5;, and &man.vga.4;.</para>
- </sect2>
</sect1>
<sect1 xml:id="device-hints">
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