[673b0d8] | 1 | <?xml version="1.0" encoding="ISO-8859-1"?>
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| 2 | <!DOCTYPE sect1 PUBLIC "-//OASIS//DTD DocBook XML V4.3//EN" "http://www.oasis-open.org/docbook/xml/4.3/docbookx.dtd" [
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| 3 | <!ENTITY % general-entities SYSTEM "../general.ent">
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| 4 | %general-entities;
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| 5 | ]>
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[3be4d97] | 6 | <sect1 id="ch-bootable-kernel" xreflabel="Linux">
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[673b0d8] | 7 | <title>Linux-&linux-version;</title>
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| 8 | <?dbhtml filename="kernel.html"?>
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| 9 |
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| 10 | <indexterm zone="ch-bootable-kernel"><primary sortas="a-Linux">Linux</primary></indexterm>
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[6370fa6] | 11 |
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[5888299] | 12 | <para>The Linux package contains the kernel and the header files.</para>
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| 13 |
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[673b0d8] | 14 | <screen>&buildtime; All default options: 4.20 SBU
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| 15 | &diskspace; All default options: 181 MB</screen>
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| 16 |
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| 17 | <para>Linux installation depends on: Bash, Binutils, Coreutils, Findutils,
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| 18 | GCC, Glibc, Grep, Gzip, Make, Modutils, Perl, Sed.</para>
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[6403026] | 19 |
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[5888299] | 20 |
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[2081905] | 21 |
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| 22 | <sect2>
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| 23 | <title>Installation of the kernel</title>
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| 24 |
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| 25 | <para>Building the kernel involves a few steps: configuration, compilation, and
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| 26 | installation. If you don't like the way this book configures the kernel, view
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| 27 | the <filename>README</filename> file in the kernel source tree for alternative
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| 28 | methods.</para>
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| 29 |
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| 30 | <para>Prepare for compilation by running the following command:</para>
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| 31 |
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| 32 | <screen><userinput>make mrproper</userinput></screen>
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| 33 |
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| 34 | <para>This ensures that the kernel tree is absolutely clean. The kernel team
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| 35 | recommends that this command be issued prior to <emphasis>each</emphasis>
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| 36 | kernel compilation. You shouldn't rely on the source tree being clean after
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[673b0d8] | 37 | un-tarring.</para>
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[2081905] | 38 |
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| 39 | <para>Configure the kernel via a menu-driven interface:</para>
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| 40 |
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| 41 | <screen><userinput>make menuconfig</userinput></screen>
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| 42 |
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| 43 | <para><userinput>make oldconfig</userinput> may be more appropriate in some
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| 44 | situations. See the <filename>README</filename> file for more
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| 45 | information.</para>
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| 46 |
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| 47 | <para>If you wish, you may skip kernel configuration by simply copying the
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| 48 | kernel config file, <filename>.config</filename>, from your host system
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[673b0d8] | 49 | (assuming it is available) to the unpacked <filename class="directory">linux-&linux-version;</filename>
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| 50 | directory. However, we
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[2081905] | 51 | don't recommend this option. You're much better off exploring all the
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| 52 | configuration menus and creating your own kernel configuration from
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| 53 | scratch.</para>
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| 54 |
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| 55 | <para>For POSIX shared memory support, ensure that the kernel config option
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[673b0d8] | 56 | <quote>Virtual memory file system support</quote> is enabled. It resides within
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| 57 | the <quote>File systems</quote> menu and is normally enabled by default.</para>
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[2081905] | 58 |
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[9dfc02f] | 59 | <note><para>NPTL requires the kernel to be compiled with GCC 3.x, in this case
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| 60 | &gcc-version;. Compiling with 2.95.x is known to cause failures in the glibc
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| 61 | testsuite, so do <emphasis>not</emphasis> compile the kernel with gcc 2.95.x
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| 62 | unless you know what you're getting yourself into.</para></note>
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[2081905] | 63 |
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[9dfc02f] | 64 | <para>Compile the kernel image and modules:</para>
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[2081905] | 65 |
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[9dfc02f] | 66 | <screen><userinput>make</userinput></screen>
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[2081905] | 67 |
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| 68 | <para>If you intend to use kernel modules, you will need an
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[9dfc02f] | 69 | <filename>/etc/modprobe.conf</filename> file. Information pertaining
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[2081905] | 70 | to modules and to kernel configuration in general may be found in the
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| 71 | kernel documentation, which is found in the
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[9dfc02f] | 72 | <filename>linux-&linux-version;/Documentation</filename> directory. The
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[2081905] | 73 | modules.conf man page and the kernel HOWTO at
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[673b0d8] | 74 | <ulink url="http://www.tldp.org/HOWTO/Kernel-HOWTO.html"/> may also be of
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[2081905] | 75 | interest to you.</para>
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| 76 |
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| 77 | <para>Install the modules:</para>
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| 78 |
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[9dfc02f] | 79 | <screen><userinput>make modules_install</userinput></screen>
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[2081905] | 80 |
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[b157558] | 81 | <para>If you have a lot of modules and very little space, you may want to
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| 82 | consider stripping and compressing the modules. For most people such compression
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| 83 | isn't worth the trouble, but if you're really pressed for space, then have a look at
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| 84 | <ulink url="http://www.linux-mips.org/archives/linux-mips/2002-04/msg00031.html"/>.</para>
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| 85 |
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[2081905] | 86 | <para>Kernel compilation has finished but more steps are required to complete
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| 87 | the installation. Some files need to be copied to the <filename>/boot</filename>
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| 88 | directory.</para>
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| 89 |
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| 90 | <para>The path to the kernel image may vary depending on the platform you're
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| 91 | using. Issue the following command to install the kernel:</para>
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| 92 |
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[9dfc02f] | 93 | <screen><userinput>cp arch/i386/boot/bzImage /boot/lfskernel-&linux-version;</userinput></screen>
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[2081905] | 94 |
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| 95 | <para><filename>System.map</filename> is a symbol file for the kernel. It maps
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[673b0d8] | 96 | the function entry points of every function in the kernel API (Application Programming Interface), as well as the
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[2081905] | 97 | addresses of the kernel data structures for the running kernel. Issue the
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| 98 | following command to install the map file:</para>
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| 99 |
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[9dfc02f] | 100 | <screen><userinput>cp System.map /boot/System.map-&linux-version;</userinput></screen>
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[2081905] | 101 |
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| 102 | <para><filename>.config</filename> is the kernel configuration file that was
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| 103 | produced by the <command>make menuconfig</command> step above. It contains all
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| 104 | the config selections for the kernel that was just compiled. It's a good idea
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| 105 | to keep this file for future reference:</para>
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| 106 |
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[9dfc02f] | 107 | <screen><userinput>cp .config /boot/config-&linux-version;</userinput></screen>
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[2081905] | 108 |
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| 109 | <para>It is important to note that the files in the kernel source directory are
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| 110 | not owned by <emphasis>root</emphasis>. Whenever you unpack a package as user
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| 111 | <emphasis>root</emphasis> (like we did here inside chroot), the files end up
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| 112 | having the user and group IDs of whatever they were on the packager's computer.
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| 113 | This is usually not a problem for any other package you install because you
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| 114 | remove the source tree after the installation. But the Linux source tree is
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| 115 | often kept around for a long time, so there's a chance that whatever user ID
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| 116 | the packager used will be assigned to somebody on your machine and then that
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| 117 | person would have write access to the kernel source.</para>
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| 118 |
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| 119 | <para>If you are going to keep the kernel source tree around, you may want to
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| 120 | run <userinput>chown -R 0:0</userinput> on the
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[673b0d8] | 121 | <filename>linux-2.4.25</filename> directory to ensure all files are
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[2081905] | 122 | owned by user <emphasis>root</emphasis>.</para>
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| 123 |
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| 124 | </sect2>
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[6910868] | 125 |
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[673b0d8] | 126 |
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| 127 | <sect2 id="contents-kernel"><title>Contents of Linux</title>
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| 128 |
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| 129 | <para><emphasis>Installed files</emphasis>: the kernel, the kernel headers,
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| 130 | and the System.map</para>
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| 131 |
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| 132 | </sect2>
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| 133 |
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| 134 | <sect2><title>Short descriptions</title>
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| 135 |
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| 136 | <indexterm zone="ch-bootable-kernel kernel"><primary sortas="b-kernel">kernel</primary></indexterm>
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| 137 | <para id="kernel">The <emphasis>kernel</emphasis> is the engine of your GNU/Linux system.
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| 138 | When switching on your box, the kernel is the first part of your operating
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| 139 | system that gets loaded. It detects and initializes all the components of your
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| 140 | computer's hardware, then makes these components available as a tree of files
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| 141 | to the software, and turns a single CPU into a multi-tasking machine capable
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| 142 | of running scores of programs seemingly at the same time.</para>
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| 143 |
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| 144 | <indexterm zone="ch-bootable-kernel kernel-headers"><primary sortas="e-kernel-headers">kernel headers</primary></indexterm>
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| 145 | <para id="kernel-headers">The <emphasis>kernel headers</emphasis> define the interface to the
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| 146 | services that the kernel provides. The headers in your system's
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| 147 | <filename>include</filename> directory should <emphasis>always</emphasis> be
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| 148 | the ones against which Glibc was compiled and should therefore
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| 149 | <emphasis>not</emphasis> be replaced when upgrading the kernel.</para>
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| 150 |
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| 151 | <indexterm zone="ch-bootable-kernel System.map"><primary sortas="e-/boot/System.map">/boot/System.map</primary></indexterm>
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| 152 | <para id="System.map">The <filename>System.map</filename> file is a list of addresses and
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| 153 | symbols. It maps the entry points and addresses of all the functions and data
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| 154 | structures in the kernel.</para>
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| 155 |
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| 156 | </sect2>
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| 157 |
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| 158 |
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[5888299] | 159 |
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[6370fa6] | 160 | </sect1>
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