en/boot-installer/parameters.xml

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 <sect1 id="boot-parms"><title>Boot Parameters</title>
<para>

Boot parameters are Linux kernel parameters which are generally used
to make sure that peripherals are dealt with properly.  For the most
part, the kernel can auto-detect information about your peripherals.
However, in some cases you'll have to help the kernel a bit.

</para><para>

If this is the first time you're booting the system, try the default
boot parameters (i.e., don't try setting arguments) and see if it works
correctly. It probably will.  If not, you can reboot later and look for
any special parameters that inform the system about your hardware.

</para><para>

Information on many boot parameters can be found in the 
<ulink url="http://www.tldp.org/HOWTO/BootPrompt-HOWTO.html"> Linux
BootPrompt HOWTO</ulink>, including tips for obscure hardware.  This
section contains only a sketch of the most salient parameters.  Some
common gotchas are included below in 
<xref linkend="boot-troubleshooting"/>.

</para><para>

When the kernel boots, a message 

<informalexample><screen>

Memory:<replaceable>avail</replaceable>k/<replaceable>total</replaceable>k available 

</screen></informalexample>

should be emitted early in the process.
<replaceable>total</replaceable> should match the total amount of RAM,
in kilobytes.  If this doesn't match the actual amount of RAM you have
installed, you need to use the
<userinput>mem=<replaceable>ram</replaceable></userinput> parameter,
where <replaceable>ram</replaceable> is set to the amount of memory,
suffixed with ``k'' for kilobytes, or ``m'' for megabytes.  For
example, both <userinput>mem=65536k</userinput> and
<userinput>mem=64m</userinput> mean 64MB of RAM.

</para><para>

If your monitor is only capable of black-and-white, use the
<userinput>mono</userinput> boot argument.  Otherwise, your
installation will use color, which is the default.

</para><para condition="supports-serial-console">

If you are booting with a serial console, generally the kernel will
autodetect this 
<phrase arch="mipsel">(although not on DECstations)</phrase>
If you have a videocard (framebuffer) and a keyboard also attached to
the computer which you wish to boot via serial console, you may have
to pass the
<userinput>console=<replaceable>device</replaceable></userinput>
argument to the kernel, where <replaceable>device</replaceable> is
your serial device, which is usually something like
<filename>ttyS0</filename>.

</para><para arch="sparc">

For &arch-title; the serial devices are <filename>ttya</filename> or
<filename>ttyb</filename>.
Alternatively, set the <envar>input-device</envar> and
<envar>output-device</envar> OpenPROM variables to
<filename>ttya</filename>.

</para>


  <sect2 id="installer-args"><title>Debian Installer Arguments</title>
<para>

The installation system recognizes a few boot arguments which may be
useful. 

</para>

<variablelist>
<varlistentry>
<term>DEBCONF_PRIORITY</term>
<listitem><para>

These parameter settings will similarly set the highest priority of
messages to be displayed. 

</para><para>

With <userinput>DEBCONF_PRIORITY=critical</userinput>, the
installation system will display only critical messages and try to do
the right thing without fuss.  If problems are encountered, the
installer adjusts the priority as needed.

</para><para>

If <userinput>DEBCONF_PRIORITY=high</userinput> (the default setting),
both high and critical priority messages are shown, but medium and low
priority messages are skipped. When
<userinput>DEBCONF_PRIORITY=low</userinput> is used, all messages are
shown.

</para></listitem>
</varlistentry>


<varlistentry>
<term>DEBCONF_FRONTEND</term>
<listitem><para>

This boot parameter controls the type of user interface used for the
installer. The current possible parameter settings are:

<itemizedlist>
<listitem>
<para><userinput>DEBCONF_FRONTEND=noninteractive</userinput></para>
</listitem><listitem>
<para><userinput>DEBCONF_FRONTEND=text</userinput></para>
</listitem><listitem>
<para><userinput>DEBCONF_FRONTEND=newt</userinput></para>
</listitem><listitem>
<para><userinput>DEBCONF_FRONTEND=slang</userinput></para>
</listitem><listitem>
<para><userinput>DEBCONF_FRONTEND=ncurses</userinput></para>
</listitem><listitem>
<para><userinput>DEBCONF_FRONTEND=bogl</userinput></para>
</listitem><listitem>
<para><userinput>DEBCONF_FRONTEND=gtk</userinput></para>
</listitem><listitem>
<para><userinput>DEBCONF_FRONTEND=corba</userinput></para>
</listitem>
</itemizedlist>

The default front end is <userinput>DEBCONF_FRONTEND=newt</userinput>.
<userinput>DEBCONF_FRONTEND=text</userinput> may be preferable for
serial console installs. Other frontends but
<userinput>newt</userinput> are not available on default install
media, so this is not very useful right now.

</para></listitem>
</varlistentry>


<varlistentry>
<term>BOOT_DEBUG</term>
<listitem><para>

Passing this boot parameter will cause the boot to be more verbosely 
logged.

<variablelist>
<varlistentry>
<term><userinput>BOOT_DEBUG=0</userinput></term>
<listitem><para>This is the default.</para></listitem>
</varlistentry>

<varlistentry>
<term><userinput>BOOT_DEBUG=1</userinput></term>
<listitem><para>More verbose than usual.</para></listitem>
</varlistentry>

<varlistentry>
<term><userinput>BOOT_DEBUG=2</userinput></term>
<listitem><para>Lots of debugging information.</para></listitem>
</varlistentry>

<varlistentry>
<term><userinput>BOOT_DEBUG=3</userinput></term>
<listitem><para>

Shells are run at various points in the boot process to allow detailed
debugging. Exit the shell to continue the boot.

</para></listitem>
</varlistentry>
</variablelist>

</para></listitem>
</varlistentry>


<varlistentry>
<term>INSTALL_MEDIA_DEV</term>
<listitem><para>

The value of the parameter is the path to the device to load the
Debian installer from. For example,
<userinput>INSTALL_MEDIA_DEV=/dev/floppy/0</userinput>

</para><para>

The boot floppy, which normally scans all floppys and USB storage
devices it can to find the root floppy, can be overridden by this
parameter to only look at the one device.

</para></listitem>
</varlistentry>

<varlistentry>
<term>debian-installer/framebuffer</term>
<listitem><para>

Some architectures use the kernel framebuffer to offer installation in
a number of languages. If framebuffer causes a problem on your system
you can disable the feature by the parameter
<userinput>debian-installer/framebuffer=false</userinput>. Problem
symptoms are error messages about bterm or bogl, a blank screen, or
a freeze within a few minutes after starting the install.

</para><para arch="i386">

The <userinput>video=vga16:off</userinput> argument may also be used
to disable the framebuffer. Such problems have been reported on a Dell
Inspiron with Mobile Radeon card.

</para><para arch="m68k">

Such problems have been reported on the Amiga 1200 and SE/30.

</para><para arch="hppa">

Such problems have been reported on hppa.

</para></listitem>
</varlistentry>

<varlistentry>
<term>debian-installer/probe/usb</term>
<listitem><para>

Set to <userinput>false</userinput> to prevent probing for USB on
boot, if that causes problems.

</para></listitem>
</varlistentry>

<varlistentry>
<term>netcfg/use_dhcp</term>
<listitem><para>

By default, the &d-i; automatically probes for network configuration
via DHCP. If the probe succeeds, you won't have a chance to review and
chage the obtained settings. You can get to the manual network setup
only in case the DHCP probe fails.

</para><para>

If you have a DHCP server on your local network, but want to avoid it
because e.g. it gives wrong answers, you can use the parameter
<userinput>netcfg/use_dhcp=false</userinput> to prevent configuring
the network with DHCP and to enter the information manually.

</para></listitem>
</varlistentry>

<varlistentry>
<term>hw-detect/start_pcmcia</term>
<listitem><para>

Set to <userinput>false</userinput> to prevent starting PCMCIA
services, if that causes problems. Some laptops are well known for
this misbehaviour.

</para></listitem>
</varlistentry>

</variablelist>
  </sect2>
 </sect1>

1	toff	5236	<!-- retain these comments for translator revision tracking -->
2	joeyh	11648	<!-- $Id$ -->
3	toff	5236
4			<sect1 id="boot-parms"><title>Boot Parameters</title>
5			<para>
6
7			Boot parameters are Linux kernel parameters which are generally used
8			to make sure that peripherals are dealt with properly. For the most
9			part, the kernel can auto-detect information about your peripherals.
10			However, in some cases you'll have to help the kernel a bit.
11
12			</para><para>
13
14			If this is the first time you're booting the system, try the default
15			boot parameters (i.e., don't try setting arguments) and see if it works
16			correctly. It probably will. If not, you can reboot later and look for
17			any special parameters that inform the system about your hardware.
18
19			</para><para>
20
21	toff	5907	Information on many boot parameters can be found in the
22			<ulink url="http://www.tldp.org/HOWTO/BootPrompt-HOWTO.html"> Linux
23	toff	5236	BootPrompt HOWTO</ulink>, including tips for obscure hardware. This
24			section contains only a sketch of the most salient parameters. Some
25			common gotchas are included below in
26	toff	5338	<xref linkend="boot-troubleshooting"/>.
27	toff	5236
28			</para><para>
29
30			When the kernel boots, a message
31
32			<informalexample><screen>
33
34			Memory:<replaceable>avail</replaceable>k/<replaceable>total</replaceable>k available
35
36			</screen></informalexample>
37
38			should be emitted early in the process.
39			<replaceable>total</replaceable> should match the total amount of RAM,
40			in kilobytes. If this doesn't match the actual amount of RAM you have
41			installed, you need to use the
42			<userinput>mem=<replaceable>ram</replaceable></userinput> parameter,
43			where <replaceable>ram</replaceable> is set to the amount of memory,
44			suffixed with ``k'' for kilobytes, or ``m'' for megabytes. For
45			example, both <userinput>mem=65536k</userinput> and
46			<userinput>mem=64m</userinput> mean 64MB of RAM.
47
48			</para><para>
49
50			If your monitor is only capable of black-and-white, use the
51			<userinput>mono</userinput> boot argument. Otherwise, your
52			installation will use color, which is the default.
53
54			</para><para condition="supports-serial-console">
55
56			If you are booting with a serial console, generally the kernel will
57			autodetect this
58			<phrase arch="mipsel">(although not on DECstations)</phrase>
59			If you have a videocard (framebuffer) and a keyboard also attached to
60			the computer which you wish to boot via serial console, you may have
61			to pass the
62			<userinput>console=<replaceable>device</replaceable></userinput>
63			argument to the kernel, where <replaceable>device</replaceable> is
64	mck	5692	your serial device, which is usually something like
65			<filename>ttyS0</filename>.
66	toff	5236
67	toff	5338	</para><para arch="sparc">
68	toff	5236
69	mck-guest	7337	For &arch-title; the serial devices are <filename>ttya</filename> or
70	mck	5692	<filename>ttyb</filename>.
71			Alternatively, set the <envar>input-device</envar> and
72			<envar>output-device</envar> OpenPROM variables to
73			<filename>ttya</filename>.
74	toff	5236
75			</para>
76
77
78			<sect2 id="installer-args"><title>Debian Installer Arguments</title>
79			<para>
80
81			The installation system recognizes a few boot arguments which may be
82			useful.
83
84			</para>
85
86			<variablelist>
87			<varlistentry>
88	toff	5907	<term>DEBCONF_PRIORITY</term>
89	toff	5236	<listitem><para>
90
91	toff	5907	These parameter settings will similarly set the highest priority of
92			messages to be displayed.
93	toff	5236
94	toff	5907	</para><para>
95
96	mck-guest	7337	With <userinput>DEBCONF_PRIORITY=critical</userinput>, the
97			installation system will display only critical messages and try to do
98			the right thing without fuss. If problems are encountered, the
99			installer adjusts the priority as needed.
100	toff	5907
101			</para><para>
102
103	mck-guest	7337	If <userinput>DEBCONF_PRIORITY=high</userinput> (the default setting),
104			both high and critical priority messages are shown, but medium and low
105			priority messages are skipped. When
106			<userinput>DEBCONF_PRIORITY=low</userinput> is used, all messages are
107			shown.
108	toff	5907
109	toff	5236	</para></listitem>
110			</varlistentry>
111
112	toff	5907
113	toff	5236	<varlistentry>
114	toff	5907	<term>DEBCONF_FRONTEND</term>
115			<listitem><para>
116	toff	5236
117	toff	5907	This boot parameter controls the type of user interface used for the
118			installer. The current possible parameter settings are:
119
120			<itemizedlist>
121	mck-guest	7337	<listitem>
122			<para><userinput>DEBCONF_FRONTEND=noninteractive</userinput></para>
123			</listitem><listitem>
124			<para><userinput>DEBCONF_FRONTEND=text</userinput></para>
125			</listitem><listitem>
126			<para><userinput>DEBCONF_FRONTEND=newt</userinput></para>
127			</listitem><listitem>
128			<para><userinput>DEBCONF_FRONTEND=slang</userinput></para>
129			</listitem><listitem>
130			<para><userinput>DEBCONF_FRONTEND=ncurses</userinput></para>
131			</listitem><listitem>
132			<para><userinput>DEBCONF_FRONTEND=bogl</userinput></para>
133			</listitem><listitem>
134			<para><userinput>DEBCONF_FRONTEND=gtk</userinput></para>
135			</listitem><listitem>
136			<para><userinput>DEBCONF_FRONTEND=corba</userinput></para>
137			</listitem>
138	toff	5907	</itemizedlist>
139
140	mck-guest	7337	The default front end is <userinput>DEBCONF_FRONTEND=newt</userinput>.
141	mck-guest	14350	<userinput>DEBCONF_FRONTEND=text</userinput> may be preferable for
142			serial console installs. Other frontends but
143			<userinput>newt</userinput> are not available on default install
144			media, so this is not very useful right now.
145	toff	5907
146			</para></listitem>
147			</varlistentry>
148
149
150			<varlistentry>
151			<term>BOOT_DEBUG</term>
152	toff	5236	<listitem><para>
153
154	toff	5907	Passing this boot parameter will cause the boot to be more verbosely
155			logged.
156	toff	5236
157	toff	5907	<variablelist>
158			<varlistentry>
159	mck-guest	9780	<term><userinput>BOOT_DEBUG=0</userinput></term>
160	toff	5907	<listitem><para>This is the default.</para></listitem>
161			</varlistentry>
162
163			<varlistentry>
164	mck-guest	9780	<term><userinput>BOOT_DEBUG=1</userinput></term>
165	toff	5907	<listitem><para>More verbose than usual.</para></listitem>
166			</varlistentry>
167
168			<varlistentry>
169	mck-guest	9780	<term><userinput>BOOT_DEBUG=2</userinput></term>
170	toff	5907	<listitem><para>Lots of debugging information.</para></listitem>
171			</varlistentry>
172
173			<varlistentry>
174	mck-guest	9780	<term><userinput>BOOT_DEBUG=3</userinput></term>
175	toff	5907	<listitem><para>
176
177			Shells are run at various points in the boot process to allow detailed
178			debugging. Exit the shell to continue the boot.
179
180	toff	5236	</para></listitem>
181			</varlistentry>
182	toff	5907	</variablelist>
183	toff	5236
184	toff	5907	</para></listitem>
185			</varlistentry>
186
187
188	toff	5236	<varlistentry>
189	toff	5907	<term>INSTALL_MEDIA_DEV</term>
190	toff	5236	<listitem><para>
191
192	toff	5907	The value of the parameter is the path to the device to load the
193			Debian installer from. For example,
194			<userinput>INSTALL_MEDIA_DEV=/dev/floppy/0</userinput>
195	toff	5236
196	toff	5907	</para><para>
197
198			The boot floppy, which normally scans all floppys and USB storage
199			devices it can to find the root floppy, can be overridden by this
200	joeyh	6176	parameter to only look at the one device.
201	toff	5907
202	toff	5236	</para></listitem>
203			</varlistentry>
204
205			<varlistentry>
206	mck-guest	9780	<term>debian-installer/framebuffer</term>
207	toff	5236	<listitem><para>
208
209			Some architectures use the kernel framebuffer to offer installation in
210			a number of languages. If framebuffer causes a problem on your system
211	mck-guest	9780	you can disable the feature by the parameter
212			<userinput>debian-installer/framebuffer=false</userinput>. Problem
213			symptoms are error messages about bterm or bogl, a blank screen, or
214			a freeze within a few minutes after starting the install.
215	toff	5236
216			</para><para arch="i386">
217
218	toff	5338	The <userinput>video=vga16:off</userinput> argument may also be used
219	toff	5907	to disable the framebuffer. Such problems have been reported on a Dell
220			Inspiron with Mobile Radeon card.
221	toff	5236
222			</para><para arch="m68k">
223
224			Such problems have been reported on the Amiga 1200 and SE/30.
225
226			</para><para arch="hppa">
227
228			Such problems have been reported on hppa.
229
230			</para></listitem>
231			</varlistentry>
232
233	mck-guest	14350	<varlistentry>
234			<term>debian-installer/probe/usb</term>
235			<listitem><para>
236
237			Set to <userinput>false</userinput> to prevent probing for USB on
238			boot, if that causes problems.
239
240			</para></listitem>
241			</varlistentry>
242
243			<varlistentry>
244			<term>netcfg/use_dhcp</term>
245			<listitem><para>
246
247			By default, the &d-i; automatically probes for network configuration
248			via DHCP. If the probe succeeds, you won't have a chance to review and
249			chage the obtained settings. You can get to the manual network setup
250			only in case the DHCP probe fails.
251
252			</para><para>
253
254			If you have a DHCP server on your local network, but want to avoid it
255			because e.g. it gives wrong answers, you can use the parameter
256			<userinput>netcfg/use_dhcp=false</userinput> to prevent configuring
257			the network with DHCP and to enter the information manually.
258
259			</para></listitem>
260			</varlistentry>
261
262			<varlistentry>
263			<term>hw-detect/start_pcmcia</term>
264			<listitem><para>
265
266			Set to <userinput>false</userinput> to prevent starting PCMCIA
267			services, if that causes problems. Some laptops are well known for
268			this misbehaviour.
269
270			</para></listitem>
271			</varlistentry>
272
273	toff	5236	</variablelist>
274			</sect2>
275			</sect1>
276