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@@ -207,14 +207,93 @@ EOF</userinput></screen>
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</sect3>
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</sect2>
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+ <sect2>
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+ <title>Udev Bootscripts</title>
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+
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+ <para>The first LFS bootscript,
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+ <filename>/etc/init.d/mountvirtfs</filename> will copy any devices
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+ located in <filename class="directory">/lib/udev/devices</filename> to
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+ <filename class="directory">/dev</filename>. This is necessary because
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+ some devices, directories, and symlinks are needed before the dynamic
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+ device handling processes are available during the early stages of
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+ booting a system, or are required by <command>udevd</command> itself.
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+ Creating static device nodes in <filename
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+ class="directory">/lib/udev/devices</filename> also provides an easy
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+ workaround for devices that are not supported by the dynamic device
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+ handling infrastructure.</para>
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+
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+ <para>The <filename>/etc/rc.d/init.d/udev</filename> initscript starts
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+ <command>udevd</command>, triggers any "coldplug" devices that have
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+ already been created by the kernel and waits for any rules to complete.
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+ The script also unsets the uevent handler from the default of
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+ <filename>/sbin/hotplug </filename>. This is done because the kernel no
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+ longer needs to call out to an external binary. Instead
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+ <command>udevd</command> will listen on a netlink socket for uevents that
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+ the kernel raises.</para>
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+
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+ <para>The <command>/etc/rc.d/init.d/udev_retry</command> initscript takes
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+ care of re-triggering events for subsystems whose rules may rely on
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+ filesystems that are not mounted until the <command>mountfs</command>
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+ script is run (in particular, <filename class="directory">/usr</filename>
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+ and <filename class="directory">/var</filename> may cause this). This
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+ script runs after the <command>mountfs</command> script, so those rules
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+ (if re-triggered) should succeed the second time around. It is
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+ configured from the <filename>/etc/sysconfig/udev_retry</filename> file;
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+ any words in this file other than comments are considered subsystem names
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+ to trigger at retry time. To find the subsystem of a device, use
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+ <command>udevadm info --attribute-walk <device></command> where
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+ <device> is an absolute path in /dev or /sys such as /dev/sr0 or
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+ /sys/class/rtc.</para>
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+
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+ <sect3>
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+ <title>Module Loading</title>
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+
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+ <para>Device drivers compiled as modules may have aliases built into them.
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+ Aliases are visible in the output of the <command>modinfo</command>
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+ program and are usually related to the bus-specific identifiers of devices
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+ supported by a module. For example, the <emphasis>snd-fm801</emphasis>
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+ driver supports PCI devices with vendor ID 0x1319 and device ID 0x0801,
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+ and has an alias of <quote>pci:v00001319d00000801sv*sd*bc04sc01i*</quote>.
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+ For most devices, the bus driver exports the alias of the driver that
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+ would handle the device via <systemitem
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+ class="filesystem">sysfs</systemitem>. E.g., the
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+ <filename>/sys/bus/pci/devices/0000:00:0d.0/modalias</filename> file
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+ might contain the string
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+ <quote>pci:v00001319d00000801sv00001319sd00001319bc04sc01i00</quote>.
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+ The default rules provided with Udev will cause <command>udevd</command>
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+ to call out to <command>/sbin/modprobe</command> with the contents of the
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+ <envar>MODALIAS</envar> uevent environment variable (which should be the
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+ same as the contents of the <filename>modalias</filename> file in sysfs),
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+ thus loading all modules whose aliases match this string after wildcard
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+ expansion.</para>
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+
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+ <para>In this example, this means that, in addition to
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+ <emphasis>snd-fm801</emphasis>, the obsolete (and unwanted)
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+ <emphasis>forte</emphasis> driver will be loaded if it is
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+ available. See below for ways in which the loading of unwanted drivers can
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+ be prevented.</para>
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+
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+ <para>The kernel itself is also able to load modules for network
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+ protocols, filesystems and NLS support on demand.</para>
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+
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+ </sect3>
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+
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+ <sect3>
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+ <title>Handling Hotpluggable/Dynamic Devices</title>
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+
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+ <para>When you plug in a device, such as a Universal Serial Bus (USB) MP3
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+ player, the kernel recognizes that the device is now connected and
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+ generates a uevent. This uevent is then handled by
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+ <command>udevd</command> as described above.</para>
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+
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+ </sect3>
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+ </sect2>
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+
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<sect2 id="ch-scripts-clock">
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<title>Configuring the System Clock</title>
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- <sect3 id="ch-scripts-setclock">
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- <title>System V Clock Configuration</title>
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-
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- <indexterm zone="ch-scripts-setclock">
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- <primary sortas="d-setclock">setclock</primary>
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+ <indexterm zone="ch-scripts-clock">
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+ <primary sortas="d-scripts-setclock">setclock</primary>
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<secondary>configuring</secondary></indexterm>
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<para>The <command>setclock</command> script reads the time from the hardware
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@@ -268,7 +347,6 @@ EOF</userinput></screen>
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<note><para>The CLOCKPARAMS and UTC paramaters may be alternatively set
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in the <filename>/etc/sysconfig/rc.site</filename> file.</para></note>
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- </sect3>
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</sect2>
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<sect2 id="ch-scripts-console">
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Bruce Dubbs