diff options
Diffstat (limited to 'slackbook/html/system-configuration-kernel.html')
| -rw-r--r-- | slackbook/html/system-configuration-kernel.html | 354 |
1 files changed, 354 insertions, 0 deletions
diff --git a/slackbook/html/system-configuration-kernel.html b/slackbook/html/system-configuration-kernel.html new file mode 100644 index 00000000..7934fec4 --- /dev/null +++ b/slackbook/html/system-configuration-kernel.html @@ -0,0 +1,354 @@ +<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" + "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> +<html xmlns="http://www.w3.org/1999/xhtml"> +<head> +<meta name="generator" content="HTML Tidy, see www.w3.org" /> +<title>Selecting a Kernel</title> +<meta name="GENERATOR" content="Modular DocBook HTML Stylesheet Version 1.7" /> +<link rel="HOME" title="Slackware Linux Essentials" href="index.html" /> +<link rel="UP" title="System Configuration" href="system-configuration.html" /> +<link rel="PREVIOUS" title="System Configuration" href="system-configuration.html" /> +<link rel="NEXT" title="Network Configuration" href="network-configuration.html" /> +<link rel="STYLESHEET" type="text/css" href="docbook.css" /> +<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1" /> +</head> +<body class="SECT1" bgcolor="#FFFFFF" text="#000000" link="#0000FF" vlink="#840084" +alink="#0000FF"> +<div class="NAVHEADER"> +<table summary="Header navigation table" width="100%" border="0" cellpadding="0" +cellspacing="0"> +<tr> +<th colspan="3" align="center">Slackware Linux Essentials</th> +</tr> + +<tr> +<td width="10%" align="left" valign="bottom"><a href="system-configuration.html" +accesskey="P">Prev</a></td> +<td width="80%" align="center" valign="bottom">Chapter 4 System Configuration</td> +<td width="10%" align="right" valign="bottom"><a href="network-configuration.html" +accesskey="N">Next</a></td> +</tr> +</table> + +<hr align="LEFT" width="100%" /> +</div> + +<div class="SECT1"> +<h1 class="SECT1"><a id="SYSTEM-CONFIGURATION-KERNEL" +name="SYSTEM-CONFIGURATION-KERNEL">4.2 Selecting a Kernel</a></h1> + +<p>The kernel is the part of the operating system that provides hardware access, process +control, and overall system control. The kernel contains support for your hardware +devices, so picking one for your system is an important setup step.</p> + +<p>Slackware provides more than a dozen precompiled kernels that you can pick from, each +with a standard set of drivers and additional specific drivers. You can run one of the +precompiled kernels or you can build your own kernel from source. Either way, you need to +make sure that your kernel has the hardware support your system needs.</p> + +<div class="SECT2"> +<h2 class="SECT2"><a id="AEN1581" name="AEN1581">4.2.1 The <tt +class="FILENAME">/kernels</tt> Directory on the Slackware CD-ROM</a></h2> + +<p>The precompiled Slackware kernels are available in the <tt +class="FILENAME">/kernels</tt> directory on the Slackware CD-ROM or on the FTP site in +the main Slackware directory. The available kernels change as new releases are made, so +the documentation in that directory is always the authoritative source. The <tt +class="FILENAME">/kernels</tt> directory has subdirectories for each kernel available. +The subdirectories have the same name as their accompanying boot disk. In each +subdirectory you will find the following files:</p> + +<div class="INFORMALTABLE"><a id="AEN1587" name="AEN1587"></a> +<table border="0" frame="void" width="100%" class="CALSTABLE"> +<col width="33%" /> +<col width="67%" /> +<thead> +<tr> +<th>File</th> +<th>Purpose</th> +</tr> +</thead> + +<tbody> +<tr> +<td><tt class="FILENAME">System.map</tt></td> +<td>The system map file for this kernel</td> +</tr> + +<tr> +<td><tt class="FILENAME">bzImage</tt></td> +<td>The actual kernel image</td> +</tr> + +<tr> +<td><tt class="FILENAME">config</tt></td> +<td>The source configuration file for this kernel</td> +</tr> +</tbody> +</table> +</div> + +<p>To use a kernel, copy the <tt class="FILENAME">System.map</tt> and <tt +class="FILENAME">config</tt> files to your <tt class="FILENAME">/boot</tt> directory and +copy the kernel image to <tt class="FILENAME">/boot/vmlinuz</tt>. Run <tt +class="COMMAND">/sbin/lilo</tt>(8) to install LILO for the new kernel, and then reboot +your system. That's all there is to installing a new kernel.</p> + +<p>The kernels that end with a .i are IDE kernels. That is, they include no SCSI support +in the base kernel. The kernels that end with .s are SCSI kernels. They include all the +IDE support in .i kernels, plus SCSI support.</p> +</div> + +<div class="SECT2"> +<h2 class="SECT2"><a id="SYSTEM-CONFIGURATION-KERNEL-COMPILE" +name="SYSTEM-CONFIGURATION-KERNEL-COMPILE">4.2.2 Compiling a Kernel from Source</a></h2> + +<p>The question “Should I compile a kernel for my system?” is often asked by +new users. The answer is a definite maybe. There are few instances where you will need to +compile a kernel specific to your system. Most users can use a precompiled kernel and the +loadable kernel modules to achieve a fully working system. You will want to compile a +kernel for your system if you are upgrading kernel versions to one that we do not +currently offer in Slackware, or if you have patched the kernel source to get special +device support that is not in the native kernel source. Anyone with an SMP system will +definitely want to compile a kernel with SMP support. Also, many users find a custom +compiled kernel runs much faster on their machine. You may find it useful to compile the +kernel with optimizations for the specific processor in your machine.</p> + +<p>Building your own kernel is not that hard. The first step is to make sure you have the +kernel source installed on your system. Make sure that you installed the packages from +the K series during the installation. You will also want to make sure you have the D +series installed, specifically the C compiler, GNU make, and GNU binutils. In general, +it's a good idea to have the entire D series installed if you plan on doing any kind of +development. You can also download the latest kernel source from <a +href="http://www.kernel.org/mirrors" target="_top">http://www.kernel.org/mirrors</a>.</p> + +<div class="SECT3"> +<h3 class="SECT3"><a id="AEN1624" name="AEN1624">4.2.2.1 Linux Kernel version 2.4.x +Compilation</a></h3> + +<table border="0" bgcolor="#E0E0E0" width="100%"> +<tr> +<td> +<pre class="SCREEN"> +<samp class="PROMPT">%</samp> <kbd class="USERINPUT">su -</kbd> +Password: +<samp class="PROMPT">#</samp> <kbd class="USERINPUT">cd /usr/src/linux</kbd> +</pre> +</td> +</tr> +</table> + +<p>The first step is to bring the kernel source into its base state. We issue this +command to do that (note, you may wish to back-up the <tt class="FILENAME">.config</tt> +file as this command will delete it without warning):</p> + +<table border="0" bgcolor="#E0E0E0" width="100%"> +<tr> +<td> +<pre class="SCREEN"> +<samp class="PROMPT">#</samp> <kbd class="USERINPUT">make mrproper</kbd> +</pre> +</td> +</tr> +</table> + +<p>Now you can configure the kernel for your system. The current kernel offers three ways +of doing this. The first is the original text-based question and answer system. It asks a +bunch of questions and then builds a configuration file. The problem with this method is +that if you mess up, you must start over. The method that most people prefer is the menu +driven one. Lastly, there is an X-based kernel configuration tool. Pick the one you want +and issue the appropriate command:</p> + +<table border="0" bgcolor="#E0E0E0" width="100%"> +<tr> +<td> +<pre class="SCREEN"> +<samp class="PROMPT">#</samp> <kbd +class="USERINPUT">make config</kbd> (text-based Q&A version) +<samp class="PROMPT">#</samp> <kbd +class="USERINPUT">make menuconfig</kbd> (menu driven, text-based version) +<samp class="PROMPT">#</samp> <kbd +class="USERINPUT">make xconfig</kbd> (X-based version, make sure you are in X first) +</pre> +</td> +</tr> +</table> + +<div class="FIGURE"><a id="SYSTEM-CONFIGURATION-MAKE-MENUCONFIG" +name="SYSTEM-CONFIGURATION-MAKE-MENUCONFIG"></a> +<p><b>Figure 4-1. Kernel Configuration Menu</b></p> + +<p><img src="system-configuration/make-menuconfig-w.png" /></p> +</div> + +<p>New users will probably find <tt class="COMMAND">menuconfig</tt> to be the easiest to +use. Help screens are provided that explain the various parts of the kernel. After +configuring your kernel, exit the configuration program. It will write the necessary +configuration files. Now we can prepare the source tree for a build:</p> + +<table border="0" bgcolor="#E0E0E0" width="100%"> +<tr> +<td> +<pre class="SCREEN"> +<samp class="PROMPT">#</samp> <kbd class="USERINPUT">make dep</kbd> +<samp class="PROMPT">#</samp> <kbd class="USERINPUT">make clean</kbd> +</pre> +</td> +</tr> +</table> + +<p>The next step is to compile the kernel. First try issuing the <tt +class="COMMAND">bzImage</tt> command below.</p> + +<table border="0" bgcolor="#E0E0E0" width="100%"> +<tr> +<td> +<pre class="SCREEN"> +<samp class="PROMPT">#</samp> <kbd class="USERINPUT">make bzImage</kbd> +</pre> +</td> +</tr> +</table> + +<p>This may take a while, depending on your CPU speed. During the build process, you will +see the compiler messages. After building the kernel image, you will want to build any +parts of the kernel that you flagged as modular.</p> + +<table border="0" bgcolor="#E0E0E0" width="100%"> +<tr> +<td> +<pre class="SCREEN"> +<samp class="PROMPT">#</samp> <kbd class="USERINPUT">make modules</kbd> +</pre> +</td> +</tr> +</table> + +<p>We can now install the kernel and modules that you compiled. To install the kernel on +a Slackware system, these commands should be issued:</p> + +<table border="0" bgcolor="#E0E0E0" width="100%"> +<tr> +<td> +<pre class="SCREEN"> +<samp class="PROMPT">#</samp> <kbd +class="USERINPUT">mv /boot/vmlinuz /boot/vmlinuz.old</kbd> +<samp class="PROMPT">#</samp> <kbd +class="USERINPUT">cat arch/i386/boot/bzImage > /vmlinuz</kbd> +<samp class="PROMPT">#</samp> <kbd +class="USERINPUT">mv /boot/System.map /boot/System.map.old</kbd> +<samp class="PROMPT">#</samp> <kbd class="USERINPUT">cp System.map /boot/System.map</kbd> +<samp class="PROMPT">#</samp> <kbd class="USERINPUT">make modules_install</kbd> +</pre> +</td> +</tr> +</table> + +<p>You will want to edit <tt class="FILENAME">/etc/lilo.conf</tt> and add a section to +boot your old kernel in case your new one does not work. After doing that, run <tt +class="COMMAND">/sbin/lilo</tt> to install the new boot block. You can now reboot with +your new kernel.</p> +</div> + +<div class="SECT3"> +<h3 class="SECT3"><a id="AEN1686" name="AEN1686">4.2.2.2 Linux Kernel Version +2.6.x</a></h3> + +<p>The compilation of a 2.6 kernel is only slightly different from a 2.4 or a 2.2 kernel, +but it is important that you understand the differences before delving in. It's no longer +necessary to run <tt class="COMMAND">make dep</tt> and <tt class="COMMAND">make +clean</tt>. Also, the kernel compilation process is not as verbose in the 2.6 kernel +series. This results in a build process that is easier to understand, but has some short +comings as well. If you have trouble building the kernel, it's highly recommended that +you turn verbosity back up. You do this simply by appending <var class="OPTION">V=1</var> +to the build. This allows you to log more information that could help a kernel developer +or other friendly geek aid you in resolving the issue.</p> + +<table border="0" bgcolor="#E0E0E0" width="100%"> +<tr> +<td> +<pre class="SCREEN"> +<samp class="PROMPT">#</samp> <kbd class="USERINPUT">make bzImage V=1</kbd> +</pre> +</td> +</tr> +</table> +</div> +</div> + +<div class="SECT2"> +<h2 class="SECT2"><a id="SYSTEM-CONFIGURATION-KERNEL-MODULES" +name="SYSTEM-CONFIGURATION-KERNEL-MODULES">4.2.3 Using Kernel Modules</a></h2> + +<p>Kernel modules are another name for device drivers that can be inserted into a running +kernel. They allow you to extend the hardware supported by your kernel without needing to +pick another kernel or compile one yourself.</p> + +<p>Modules can also be loaded and unloaded at any time, even when the system is running. +This makes upgrading specific drivers easy for system administrators. A new module can be +compiled, the old one removed, and the new one loaded, all without rebooting the +machine.</p> + +<p>Modules are stored in the <tt class="FILENAME">/lib/modules/<var +class="REPLACEABLE">kernel version</var></tt> directory on your system. They can be +loaded at boot time through the <tt class="FILENAME">rc.modules</tt> file. This file is +very well commented and offers examples for major hardware components. To see a list of +modules that are currently active, use the <tt class="COMMAND">lsmod</tt>(1) command:</p> + +<table border="0" bgcolor="#E0E0E0" width="100%"> +<tr> +<td> +<pre class="SCREEN"> +<samp class="PROMPT">#</samp> <kbd class="USERINPUT">lsmod</kbd> +Module Size Used by +parport_pc 7220 0 +parport 7844 0 [parport_pc] +</pre> +</td> +</tr> +</table> + +<p>You can see here that I only have the parallel port module loaded. To remove a module, +you use the <tt class="COMMAND">rmmod</tt>(1) command. Modules can be loaded by the <tt +class="COMMAND">modprobe</tt>(1) or <tt class="COMMAND">insmod</tt>(1) command. <tt +class="COMMAND">modprobe</tt> is usually safer because it will load any modules that the +one you're trying to load depends on.</p> + +<p>A lot of users never have to load or unload modules by hand. They use the kernel +autoloader for module management. By default, Slackware includes <var +class="OPTION">kmod</var> in its kernels. <var class="OPTION">kmod</var> is a kernel +option that enables the kernel to automatically load modules as they are requested. For +more information on <var class="OPTION">kmod</var> and how it is configured, see <tt +class="FILENAME">/usr/src/linux/Documentation/kmod.txt</tt>. You'll have needed to have +the kernel source package, or downloaded kernel source from <a href="http://kernel.org" +target="_top">http://kernel.org</a>.</p> + +<p>More information can be found in the man pages for each of these commands, plus the +<tt class="FILENAME">rc.modules</tt> file.</p> +</div> +</div> + +<div class="NAVFOOTER"> +<hr align="LEFT" width="100%" /> +<table summary="Footer navigation table" width="100%" border="0" cellpadding="0" +cellspacing="0"> +<tr> +<td width="33%" align="left" valign="top"><a href="system-configuration.html" +accesskey="P">Prev</a></td> +<td width="34%" align="center" valign="top"><a href="index.html" +accesskey="H">Home</a></td> +<td width="33%" align="right" valign="top"><a href="network-configuration.html" +accesskey="N">Next</a></td> +</tr> + +<tr> +<td width="33%" align="left" valign="top">System Configuration</td> +<td width="34%" align="center" valign="top"><a href="system-configuration.html" +accesskey="U">Up</a></td> +<td width="33%" align="right" valign="top">Network Configuration</td> +</tr> +</table> +</div> +</body> +</html> + |