Index: en_US.ISO8859-1/books/handbook/disks/chapter.xml
===================================================================
--- en_US.ISO8859-1/books/handbook/disks/chapter.xml
+++ en_US.ISO8859-1/books/handbook/disks/chapter.xml
@@ -580,6 +580,134 @@
 	any block device, including optical drives or
 	<acronym>iSCSI</acronym> <acronym>LUN</acronym>s.</para>
     </sect2>
+
+    <sect2>
+      <title><acronym>USB</acronym> Mass Storage Target</title>
+
+      <note>
+	<para>The &man.cfumass.4; driver is a <acronym>USB</acronym>
+	  device mode driver that first became available in
+	  &os;&nbsp;12.0-CURRENT.</para>
+      </note>
+
+      <para>When running on <acronym>USB</acronym>
+	<acronym>OTG</acronym>-compliant hardware like that built into
+	many embedded boards, the &os; <acronym>USB</acronym> stack
+	can run in <emphasis>device mode</emphasis>.  Device mode
+	makes it possible for the computer to present itself as
+	different kinds	of <acronym>USB</acronym> device classes,
+	including serial ports, network adapters, and mass storage. A
+	<acronym>USB</acronym> host like a laptop or desktop computer
+	is able to access them just like physical
+	<acronym>USB</acronym> devices.</para>
+
+      <para>The &man.usb.template.4; kernel module allows the
+	<acronym>USB</acronym> stack to switch between host-side and
+	device-side automatically, depending on what is connected to
+	the <acronym>USB</acronym> port.  Connecting a
+	<acronym>USB</acronym> device like a memory stick to the
+	<acronym>USB</acronym> <acronym>OTG</acronym> port causes &os;
+	to switch to host mode. Connecting a <acronym>USB</acronym>
+	host like a computer causes &os; to switch to device
+	mode.</para>
+
+      <para>What &os; presents to the <acronym>USB</acronym> host
+	depends on the <varname>hw.usb.template</varname> sysctl.  See
+	&man.usb.template.4; for the list of available values.  Note
+	that for the host to notice the configuration change, it must
+	be either physically disconnected and reconnected, or forced
+	to rescan the <acronym>USB</acronym> bus in a system-specific
+	way.  When &os; is running on the host, &man.usbconfig.8;
+	<command>reset</command> can be used.  This also must be done
+	after loading <filename>usb_template.ko</filename> if the
+	<acronym>USB</acronym> host was already connected to the
+	<acronym>USB</acronym> <acronym>OTG</acronym> socket.</para>
+
+      <para>The <varname>hw.usb.template</varname> sysctl
+	is set to 0 by default, making &os; work as a
+	<acronym>USB</acronym> Mass Storage target.  Both
+	&man.usb.template.4; and &man.cfumass.4; kernel modules must
+	be loaded.  &man.cfumass.4; interfaces to the CTL subsystem,
+	the same one that is used for <acronym>iSCSI</acronym> or
+	Fibre Channel targets.  On the host side,
+	<acronym>USB</acronym> Mass Storage initiators can only access
+	a single <acronym>LUN</acronym>,
+	<acronym>LUN</acronym> 0.</para>
+
+      <para><acronym>USB</acronym> Mass Storage does not require the
+	&man.ctld.8; daemon to be running, although it can be used if
+	desired.  This is different from <acronym>iSCSI</acronym>.
+	Thus, there are two ways to configure the target:
+	&man.ctladm.8;, or &man.ctld.8;.  Both require the
+	<filename>cfumass.ko</filename> kernel module to be loaded.
+	The module can be loaded manually:</para>
+
+      <screen>&prompt.root; <userinput>kldload cfumass</userinput></screen>
+
+      <para>If <filename>cfumass.ko</filename> has not been built into
+	the kernel, <filename>/boot/loader.conf</filename> can be set
+	to load	the module at boot:</para>
+
+      <programlisting>cfumass_load="YES"</programlisting>
+
+      <para>A <acronym>LUN</acronym> can be created without the
+	&man.ctld.8; daemon:</para>
+
+      <screen>&prompt.root; <userinput>ctladm create -b block -o file=/data/target0</userinput></screen>
+
+      <para>This presents the contents of the image file
+	<filename>/data/target0</filename> as a <acronym>LUN</acronym>
+	to the <acronym>USB</acronym> host.  The file must exist
+	before executing the command.  To configure the
+	<acronym>LUN</acronym> at system startup, add the command to
+	<filename>/etc/rc.local</filename>.</para>
+
+      <para>&man.ctld.8; can also be used to manage
+	<acronym>LUN</acronym>s.  Create
+	<filename>/etc/ctl.conf</filename>, add a line to
+	<filename>/etc/rc.conf</filename> to make sure &man.ctld.8; is
+	automatically started at boot, and then start the
+	daemon.</para>
+
+      <para>This is an example of a simple
+	<filename>/etc/ctl.conf</filename> configuration file.  Refer
+	to &man.ctl.conf.5; for a more complete description of the
+	options.</para>
+
+      <programlisting>target naa.50015178f369f092 {
+	lun 0 {
+		path /data/target0
+		size 4G
+	}
+}</programlisting>
+
+      <para>The example creates a single target with a single
+	<acronym>LUN</acronym>.  The
+	<literal>naa.50015178f369f092</literal> is a device identifier
+	composed of 32 random hexadecimal digits.  The
+	<literal>path</literal> line defines the full path to a file
+	or zvol backing the <acronym>LUN</acronym>.  That file must
+	exist before starting &man.ctld.8;.  The second line is
+	optional and specifies the size of the
+	<acronym>LUN</acronym>.</para>
+
+      <para>To make sure the &man.ctld.8; daemon is started at
+	boot, add this line to
+	<filename>/etc/rc.conf</filename>:</para>
+
+      <programlisting>ctld_enable="YES"</programlisting>
+
+      <para>To start &man.ctld.8; now, run this command:</para>
+
+      <screen>&prompt.root; <userinput>service ctld start</userinput></screen>
+
+      <para>As the &man.ctld.8; daemon is started, it reads
+	<filename>/etc/ctl.conf</filename>.  If this file is edited
+	after the daemon starts, reload the changes so they take
+	effect immediately:</para>
+
+      <screen>&prompt.root; <userinput>service ctld reload</userinput></screen>
+    </sect2>
   </sect1>
 
   <sect1 xml:id="creating-cds">
Index: share/xml/man-refs.ent
===================================================================
--- share/xml/man-refs.ent
+++ share/xml/man-refs.ent
@@ -7060,6 +7060,7 @@
 <!ENTITY man.central.4 "<citerefentry xmlns='http://docbook.org/ns/docbook'><refentrytitle>central</refentrytitle><manvolnum>4</manvolnum></citerefentry>">
 <!ENTITY man.cfi.4 "<citerefentry xmlns='http://docbook.org/ns/docbook'><refentrytitle>cfi</refentrytitle><manvolnum>4</manvolnum></citerefentry>">
 <!ENTITY man.cfid.4 "<citerefentry xmlns='http://docbook.org/ns/docbook'><refentrytitle>cfid</refentrytitle><manvolnum>4</manvolnum></citerefentry>">
+<!ENTITY man.cfumass.4 "<citerefentry xmlns='http://docbook.org/ns/docbook'><refentrytitle>cfumass</refentrytitle><manvolnum>4</manvolnum></citerefentry>">
 <!ENTITY man.ch.4 "<citerefentry xmlns='http://docbook.org/ns/docbook'><refentrytitle>ch</refentrytitle><manvolnum>4</manvolnum></citerefentry>">
 <!ENTITY man.ciss.4 "<citerefentry xmlns='http://docbook.org/ns/docbook'><refentrytitle>ciss</refentrytitle><manvolnum>4</manvolnum></citerefentry>">
 <!ENTITY man.clkbrd.4 "<citerefentry xmlns='http://docbook.org/ns/docbook'><refentrytitle>clkbrd</refentrytitle><manvolnum>4</manvolnum></citerefentry>">