Difference between revisions of "Doc/syslinux"

From Syslinux Wiki
Jump to: navigation, search
m (Note as outdated.)
(Update to v.6.04-pre1, with additional minor corrections. Wiki formatting.)
Line 3: Line 3:
 
[[Category:Configuration]]
 
[[Category:Configuration]]
 
'''This document is partially outdated. Please see [[SYSLINUX]] and [[Config]].'''<br />
 
'''This document is partially outdated. Please see [[SYSLINUX]] and [[Config]].'''<br />
''The content of doc/syslinux.txt (release 3.72):''
+
''The content of doc/syslinux.txt (<!--release -->6.04-pre1, with minor corrections):''
  
=SYSLINUX=
+
<div style="color: black; background: none; font-weight: normal; margin: 0; padding-top: .5em; padding-bottom: .17em; border-bottom: 1px solid #aaa; font-size: 188%; text-align: center; "> <center>  The Syslinux Project </center> </div>
  
 
<center>'''A suite of bootloaders for Linux'''</center>
 
<center>'''A suite of bootloaders for Linux'''</center>
  
<center>''Copyright 1994-2008 H. Peter Anvin - All Rights Reserved''</center>
+
<center>''Copyright 1994-2011 H. Peter Anvin and contributors''</center>
  
This program is provided under the terms of the GNU General Public License, version 2 or, at your option, any later version.  There is no warranty, neither expressed nor implied, to the function of this program.  Please see the included file COPYING for details.
+
This program is provided under the terms of the GNU General Public  
 +
License, version 2 or, at your option, any later version.  There is no  
 +
warranty, neither expressed nor implied, to the function of this  
 +
program.  Please see the included file COPYING for details.
  
 
----
 
----
  
<center>SYSLINUX now has a home page at http://syslinux.zytor.com/</center>
+
<center> Syslinux now has a home page at http://syslinux.zytor.com/ </center>
  
 
----
 
----
  
 
+
The Syslinux suite contains the following boot loaders  
The SYSLINUX suite contains the following boot loaders ("derivatives"), for their respective boot media:
+
("derivatives"), for their respective boot media:
  
 
:::'''SYSLINUX''' - MS-DOS/Windows FAT filesystem
 
:::'''SYSLINUX''' - MS-DOS/Windows FAT filesystem
Line 27: Line 30:
 
:::'''EXTLINUX''' - Linux ext2/ext3 filesystem
 
:::'''EXTLINUX''' - Linux ext2/ext3 filesystem
  
For historical reasons, some of the sections in this document applies to the FAT loader only; see [[doc/pxelinux|pxelinux.txt]], [[doc/isolinux|isolinux.txt]] and [[doc/extlinux|extlinux.txt]] for what differs in these versions.
+
For historical reasons, some of the sections in this document apply
 +
to the FAT loader (SYSLINUX) only; see [[doc/pxelinux|pxelinux.txt]], [[doc/isolinux|isolinux.txt]] and  
 +
[[doc/extlinux|extlinux.txt]] for what differs in these versions
 +
The all-caps term "SYSLINUX" generally refers to the FAT loader, whereas "Syslinux"
 +
refers to the project as a whole.
  
 
Help with cleaning up the docs would be greatly appreciated.
 
Help with cleaning up the docs would be greatly appreciated.
  
  
=Options=
+
== Options ==
  
 
These are the options common to all versions of Syslinux:
 
These are the options common to all versions of Syslinux:
Line 38: Line 45:
 
::<tt>-s</tt>  Safe, slow, stupid; uses simpler code that boots better
 
::<tt>-s</tt>  Safe, slow, stupid; uses simpler code that boots better
 
::<tt>-f</tt>  Force installing
 
::<tt>-f</tt>  Force installing
 +
::<tt>-r</tt>  Raid mode.  If boot fails, tell the BIOS to boot the next <!--
 +
            --> device in the boot sequence (usually the next hard disk)  <!--
 +
            --> instead of stopping with an error message.                <!--
 +
            --> This is useful for RAID-1 booting.
  
 
These are only in the Windows version:
 
These are only in the Windows version:
Line 45: Line 56:
  
  
=CREATING A BOOTABLE LINUX FLOPPY=
+
== CREATING A BOOTABLE LINUX FLOPPY ==
  
In order to create a bootable Linux floppy using SYSLINUX, prepare a normal MS-DOS formatted floppy.  Copy one or more Linux kernel files to it, then execute the DOS command:
+
In order to create a bootable Linux floppy using SYSLINUX, prepare a  
 +
normal MS-DOS formatted floppy.  Copy one or more Linux kernel files to  
 +
it, then execute the DOS command:
  
::<tt>syslinux [-sfma][-d directory] a:</tt>
+
::<span style="white-space:nowrap;"><code>syslinux [-sfrmai][-d directory] a: [bootsecfile]</code></span>
  
(or whichever drive letter is appropriate; the [] meaning optional.)
+
(or whichever drive letter is appropriate; the {{nowrap|"<tt>[ ]</tt>"}} meaning optional).
  
Use "<tt>syslinux.com</tt>" (in the dos subdirectory of the distribution) for plain DOS (MS-DOS, DR-DOS, PC-DOS, FreeDOS...) or Win9x/ME.
+
Use "<tt>syslinux.com</tt>" (in the dos subdirectory of the distribution) for  
 +
plain DOS (MS-DOS, DR-DOS, PC-DOS, FreeDOS...) or Win9x/ME.
  
Use "<tt>syslinux.exe</tt>" (in the win32 subdirectory of the distribution) for WinNT/2000/XP.
+
Use "<tt>syslinux.exe</tt>" (in the win32 subdirectory of the distribution) for  
 +
WinNT/2000/XP.
  
 
Under Linux, execute the command:
 
Under Linux, execute the command:
  
::<tt>syslinux [-sf][-d directory][-o offset] /dev/fd0</tt>
+
::<span style="white-space:nowrap;"><code>syslinux [-sfri][-d directory][-o offset] /dev/fd0</code></span>
  
(or, again, whichever device is the correct one.)
+
(or, again, whichever device is the correct one).
  
This will alter the boot sector on the disk and copy a file named <tt>LDLINUX.SYS</tt> into its root directory (or a subdirectory, if the <tt>-d</tt> option is specified.)
+
This will alter the boot sector on the disk and copy a file named  
 +
<tt>LDLINUX.SYS</tt> into its root directory (or a subdirectory, if the <tt>-d</tt>  
 +
option is specified).
  
The <tt>-s</tt> option, if given, will install a "safe, slow and stupid" version of SYSLINUX.  This version may work on some very buggy BIOSes on which SYSLINUX would otherwise fail.  If you find a machine on which the <tt>-s</tt> option is required to make it boot reliably, please send as much info about your machine as you can, and include the failure
+
The <tt>-s</tt> option, if given, will install a "safe, slow and stupid"  
 +
version of SYSLINUX.  This version may work on some very buggy BIOSes  
 +
on which SYSLINUX would otherwise fail.  If you find a machine on  
 +
which the <tt>-s</tt> option is required to make it boot reliably, please send  
 +
as much info about your machine as you can, and include the failure  
 
mode.
 
mode.
  
The <tt>-o</tt> option is used with a disk image file and specifies the byte offset of the filesystem image in the file.
+
The <tt>-o</tt> option is used with a disk image file and specifies the byte  
 +
offset of the filesystem image in the file.
  
For the DOS and Windows installers, the <tt>-m</tt> and <tt>-a</tt> options can be used on hard drives to write a Master Boot Record (MBR), and to mark the specific partition active.
+
For the DOS and Windows installers, the <tt>-m</tt> and <tt>-a</tt> options can be used  
 +
on hard drives to write a Master Boot Record (MBR), and to mark the  
 +
specific partition active.
  
On boot time, by default, the kernel will be loaded from the image named LINUX on the boot floppy.  This default can be changed, see the section on the SYSLINUX config file.
+
<s><small><del>On boot time, by default, the kernel will be loaded from the image named  
 +
LINUX on the boot floppy.  This default can be changed, see the section  
 +
on the SYSLINUX [[#CONFIGURATION_FILE|config file]].</del></small></s>
  
If the ''Shift'' or ''Alt'' keys are held down during boot, or the ''Caps'' or ''Scroll locks'' are set, SYSLINUX will display a LILO-style "<tt>boot:</tt>" prompt.  The user can then type a kernel file name followed by any kernel parameters. The SYSLINUX loader does not need to know about the kernel file in advance; all that is required is that it is a file located in the root directory on the disk.
+
If the ''Shift'' or ''Alt'' keys are held down during boot, or the ''Caps or Scroll locks''  
 +
are set, Syslinux will display a LILO-style "<tt>boot:</tt>" prompt.  The  
 +
user can then type a kernel file name followed by any kernel parameters.  
 +
The Syslinux loader does not need to know about the kernel file in  
 +
advance; all that is required is that it is a file located in the root  
 +
directory on the disk.
  
There are two versions of the Linux installer; one in the "<tt>mtools</tt>" directory which requires no special privilege (other than write permission to the device where you are installing) but requires the mtools program suite to be available, and one in the "unix" directory which requires root privilege.
+
There are two versions of the Linux installer; one in the "<tt>mtools</tt>"  
 +
directory which requires no special privilege (other than write  
 +
permission to the device where you are installing) but requires the  
 +
mtools program suite to be available, and one in the "linux" directory  
 +
which requires root privilege.
  
  
=CONFIGURATION FILE=
+
== CONFIGURATION FILE ==
  
All the configurable defaults in SYSLINUX can be changed by putting a file called "<tt>syslinux.cfg</tt>" in the root directory of the boot disk.
+
All options here apply to [[doc/pxelinux|PXELINUX]], [[doc/isolinux|ISOLINUX]] and [[doc/extlinux|EXTLINUX]] as well as
 +
[[doc/syslinux|SYSLINUX]] unless otherwise noted. See the respective .txt files.
  
This is a text file in either UNIX or DOS format, containing one or more of the following items (case is insensitive for keywords; uppercase is used here to indicate that a word should be typed verbatim):
+
All the configurable defaults in SYSLINUX can be changed by putting a  
 +
file called "<tt>syslinux.cfg</tt>" in the root directory of the boot disk.
  
Starting with version 3.35, the configuration file can also be in either the <tt>/boot/syslinux</tt> or <tt>/syslinux</tt> directories (searched in that order.)  If that is the case, then all filenames are assumed to be relative to that same directory, unless preceded with a slash or backslash.
+
Starting with version 3.35, the configuration file can also be in  
 +
either the <tt>/boot/syslinux</tt> or <tt>/syslinux</tt> directories (searched in that  
 +
order). If that is the case, then all filenames are assumed to be  
 +
relative to that same directory, unless preceded with a slash or  
 +
backslash.
 +
 
 +
The configuration file is a text file in either UNIX or DOS format,
 +
containing one or more of the following items, each on its own line with
 +
optional leading whitespace.  Case is insensitive for keywords; upper
 +
case is used here to indicate that a word should be typed verbatim.
  
All options here applies to [[doc/pxelinux|PXELINUX]], [[doc/isolinux|ISOLINUX]] and [[doc/extlinux|EXTLINUX]] as well as [[doc/syslinux|SYSLINUX]] unless otherwise noted.  See the respective .txt files.
 
  
 
'''#''' ''comment''
 
'''#''' ''comment''
::A comment line. The whitespace after the hash mark is mandatory.
+
::A comment line. <s><small><del>The whitespace after the hash mark is mandatory.</del></small></s>
  
 
'''INCLUDE''' ''filename''
 
'''INCLUDE''' ''filename''
::Inserts the contents of another file at this point in the configuration file. Files can currently be nested up to 16 levels deep, but it is not guaranteed that more than 8 levels will be supported in the future.
+
::Inserts the contents of another file at this point in the <!--
 +
--> configuration file. Files can currently be nested up to 16 <!--
 +
--> levels deep, but it is not guaranteed that more than 8 levels <!--
 +
--> will be supported in the future.
  
 
'''DEFAULT''' ''kernel options...''
 
'''DEFAULT''' ''kernel options...''
::Sets the default command line.  If SYSLINUX boots automatically, it will act just as if the entries after DEFAULT had been typed in at the "boot:" prompt.
+
::Sets the default command line.  If Syslinux boots automatically, <!--
 +
--> it will act just as if the commands after <tt>DEFAULT</tt> had been typed <!--
 +
--> in at the "<tt>boot:</tt>" prompt.
  
::If no configuration file is present, or no <tt>DEFAULT</tt> entry is present in the config file, the default is "<tt>linux auto</tt>".
+
::If no configuration file is present, or no <tt>DEFAULT</tt> entry is <!--
 +
--> present in the config file, <!--
 +
--> <s><small><del>the default is "<tt>linux auto</tt>"</del></small></s> <!--
 +
--> an error message is displayed and <!--
 +
--> the <tt>boot:</tt> prompt is shown.
  
::'''NOTE:''' Earlier versions of SYSLINUX used to automatically append the string "<tt>auto</tt>" to whatever the user specified using the <tt>DEFAULT</tt> command.  As of version 1.54, this is no longer true, as it caused problems when using a shell as a substitute for "<tt>init.</tt>"  You may want to include this option manually.
+
::<s><small><del>'''NOTE''': Earlier versions of SYSLINUX used to automatically <!--
 +
--> append the string "<tt>auto</tt>" to whatever the user specified using <!--
 +
--> the <tt>DEFAULT</tt> command.  As of version 1.54, this is no longer <!--
 +
--> true, as it caused problems when using a shell as a substitute <!--
 +
--> for "<tt>init.</tt>"  You may want to include this option manually.</del></small></s>
 +
 
 +
'''UI''' ''module'' ''options...''
 +
::Selects a specific user interface ''module'' (typically menu.c32 <!--
 +
--> or vesamenu.c32).  The command-line interface treats this as a <!--
 +
--> directive that overrides the <tt>DEFAULT</tt> and <tt>PROMPT</tt> directives.
  
 
<!-- Hidden manual anchor, -->
 
<!-- Hidden manual anchor, -->
<!-- so to be referenced or linked (from other pages). -->
+
<!-- so it can be referenced or linked to (from other pages). -->
 
<span id="APPEND_options"></span>
 
<span id="APPEND_options"></span>
 +
<span id="APPEND"></span>
 
'''APPEND''' ''options...''
 
'''APPEND''' ''options...''
::Add one or more options to the kernel command line.  These are added both for automatic and manual boots.  The options are added at the very beginning of the kernel command line, usually permitting explicitly entered kernel options to override them.  This is the equivalent of the LILO "<tt>append</tt>" option.
+
::Add one or more options to the kernel command line.  These are <!--
 +
--> added both for automatic and manual boots.  The options are <!--
 +
--> added at the very beginning of the kernel command line, <!--
 +
--> usually permitting explicitly entered kernel options to override <!--
 +
--> them.  This is the equivalent of the LILO "<tt>append</tt>" option.
  
'''IPAPPEND''' ''flag_val''   [PXELINUX only]
+
'''SYSAPPEND''' ''bitmask''<br />
::The IPAPPEND option is available only on PXELINUX.  The ''flag_val'' is an OR of the following
+
'''IPAPPEND''' ''bitmask''
 +
::The <tt>SYSAPPEND</tt> option was introduced in Syslinux 5.10; it is an <!--
 +
--> enhancement of a previous option <tt>IPAPPEND</tt> which was only <!--
 +
--> available on PXELINUX.  ''bitmask'' is interpreted as decimal format <!--
 +
--> unless prefixed with "0x" for hexadecimal or "0" (zero) for <!--
 +
--> octal.
  
:::1: indicates that an option of the following format should be generated and added to the kernel command line:
+
:::'''1''': indicates that an option of the following format <!--
 +
--> should be generated and added to the kernel command line:
  
::::<tt>ip=<client-ip>:<boot-server-ip>:<gw-ip>:<netmask></tt>
+
::::::<span style="white-space:nowrap;"><code>ip=<client-ip>:<boot-server-ip>:<gw-ip>:<netmask></code></span>
  
 
:::... based on the input from the DHCP/BOOTP or PXE boot server.
 
:::... based on the input from the DHCP/BOOTP or PXE boot server.
  
:::'''THE USE OF THIS OPTION IS NOT RECOMMENDED'''.  If you have to use it, it is probably an indication that your network configuration is broken.  Using just "<tt>ip=dhcp</tt>" on the kernel command line is a preferrable option, or, better yet, run dhcpcd/dhclient, from an initrd if necessary.
+
:::<s><small><del>'''THE USE OF THIS OPTION IS NOT RECOMMENDED'''.  If you have to use <!--
 +
--> it, it is probably an indication that your network configuration <!--
 +
--> is broken.  Using just "<tt>ip=dhcp</tt>" on the kernel command line <!--
 +
--> is a preferrable option, or, better yet, run dhcpcd/dhclient, <!--
 +
--> from an initrd if necessary.</del></small></s>
 +
 
 +
:::'''NOTE''': The use of this option is no substitute for running a <!--
 +
--> DHCP client in the booted system.  Without regular renewals, <!--
 +
--> the lease acquired by the PXE BIOS will expire, making the <!--
 +
--> IP address available for reuse by the DHCP server.
 +
 
 +
:::This option is empty for non-PXELINUX.
 +
 
 +
:::'''2''': indicates that an option of the following format <!--
 +
--> should be generated and added to the kernel command line:
 +
 
 +
::::::<span style="white-space:nowrap;"><code>BOOTIF=<hardware-address-of-boot-interface></code></span>
 +
 
 +
:::... in dash-separated hexadecimal with leading hardware type <!--
 +
--> (same as for the configuration file; see [[doc/pxelinux|pxelinux.txt]]).
 +
 
 +
:::This allows an initrd program to determine from which <!--
 +
--> interface the system booted.
 +
 
 +
:::This option is empty for non-PXELINUX.
 +
 
 +
:::'''4''': indicates that an option of the following format <!--
 +
--> should be generated and added to the kernel command line:
 +
 
 +
::::::<span style="white-space:nowrap;"><code>SYSUUID=<system uuid></code></span>
 +
 
 +
:::... in lower case hexadecimal in the format normally used for <!--
 +
--> UUIDs (same as for the configuration file; see [[doc/pxelinux|pxelinux.txt]]).  <!--
 +
--> This may not be available if no valid UUID is found on the <!--
 +
--> system.
 +
 
 +
:::'''8''': indicate the CPU family and certain particularly <!--
 +
--> significant CPU feature bits:
 +
 
 +
::::::<span style="white-space:nowrap;"><code>CPU=<family><features></code></span>
 +
 
 +
:::The <family> is a single digit from 3 (i386) to 6 (i686 or <!--
 +
--> higher).  The following CPU features are currently reported; <!--
 +
--> additional flags may be added in the future:
 +
{|
 +
|
 +
P Physical Address Extension (PAE)
 +
V Intel Virtualization Technology (VT/VMX)
 +
T Intel Trusted Exection Technology (TXT/SMX)
 +
X Execution Disable (XD/NX)
 +
L Long Mode (x86-64)
 +
S AMD SMX virtualization
 +
|}
 +
 
 +
:::This was added in 5.10.
 +
 
 +
:::The following strings are derived from DMI/SMBIOS information <!--
 +
--> if available; these are all new in version 5.10:
 +
{|
 +
|
 +
Bit    String Significance
 +
-------------------------------------------------------------
 +
'''0x00010''' SYSVENDOR= System vendor name
 +
'''0x00020''' SYSPRODUCT= System product name
 +
'''0x00040''' SYSVERSION= System version
 +
'''0x00080''' SYSSERIAL= System serial number
 +
'''0x00100''' SYSSKU= System SKU
 +
'''0x00200''' SYSFAMILY= System family
 +
'''0x00400''' MBVENDOR= Motherboard vendor name
 +
'''0x00800''' MBPRODUCT= Motherboard product name
 +
'''0x01000''' MBVERSION= Motherboard version
 +
'''0x02000''' MBSERIAL= Motherboard serial number
 +
'''0x04000''' MBASSET= Motherboard asset tag
 +
'''0x08000''' BIOSVENDOR= BIOS vendor name
 +
'''0x10000''' BIOSVERSION= BIOS version
 +
'''0x20000''' SYSFF= System form factor
 +
|}
 +
 
 +
:::If these strings contain whitespace they are replaced with <!--
 +
--> underscores (_).
 +
 
 +
:::The system form factor value is a number defined in the SMBIOS <!--
 +
--> specification, available at <nowiki>http://www.dmtf.org/</nowiki>.  As of <!--
 +
--> version 2.7.1 of the specification, the following values are <!--
 +
--> defined:
 +
{|
 +
|
 +
  1 Other
 +
  2 Unknown
 +
  3 Desktop
 +
  4 Low Profile Desktop
 +
  5 Pizza Box
 +
  6 Mini Tower
 +
  7 Tower
 +
  8 Portable
 +
  9 Laptop
 +
10 Notebook
 +
11 Handheld
 +
12 Docking Station
 +
13 All-in-One   
 +
14 SubNotebook   
 +
15 Space-saving 
 +
16 Lunch Box     
 +
17 Main Server Chassis
 +
18 Expansion Chassis
 +
19 SubChassis
 +
20 Bus Expansion Chassis
 +
21 Peripheral Chassis
 +
22 RAID Chassis
 +
23 Rack Mount Chassis
 +
24 Sealed-case PC
 +
25 Multi-system chassis
 +
26 Compact PCI
 +
27 <!-- <s><small><del>Advanced TCI</del></small></s> -->Advanced TCA
 +
28 Blade
 +
29 Blade Enclosure
 +
|}
 +
<!-- As of version 3.2.0 of the SMBIOS specification, -->
 +
<!--  the following values are also defined: -->
 +
<!--
 +
30 Tablet
 +
31 Convertible
 +
32 Detachable
 +
33 IoT Gateway
 +
34 Embedded PC
 +
35 Mini PC
 +
36 Stick PC
 +
-->
 +
 
 +
 
 +
:::'''0x40000''': Append a file system UUID string.  <!--
 +
--> For {{nowrap|EXT2/3/4,}} this is the typical file system UUID.  <!--
 +
--> For {{nowrap|FAT12/16/32,}} this is the {{nowrap|32-bit}} file system serial number (ie DA1A-0B2E).
 +
 
 +
::::::<span style="white-space:nowrap;"><code>FSUUID=<FS-UUID></code></span>
  
:::2: indicates that an option of the following format should be generated and added to the kernel command line:
 
  
::::<tt>BOOTIF=<hardware-address-of-boot-interface></tt>
+
'''SENDCOOKIES'''&nbsp;''bitmask''&nbsp;<!--
 +
--><span style=" font-family: monospace; white-space: pre; "><!--
 +
20spaces-->                    &nbsp;</span><tt>[PXELINUX&nbsp;only]</tt>
 +
<!-- '''SENDCOOKIES'''&nbsp;''bitmask''&nbsp;--><!--
 +
--><!--<span style=" font-family: monospace; padding-left: 20ch; ">&nbsp;</span>--><!--
 +
--><!--<tt>[PXELINUX&nbsp;only]</tt> -->
 +
::When downloading files over http, the <tt>SYSAPPEND</tt> strings are <!--
 +
--> prepended with {{nowrap|"<tt>_Syslinux_</tt>"}} and sent to the server as cookies. <!--
 +
--> The cookies are URL-encoded; whitespace is *not* replaced with <!--
 +
--> underscores.
  
:::... in dash-separated hexadecimal with leading hardware type
+
::This command limits the cookies send; <tt>0</tt> means no cookies. The <!--
:::(same as for the configuration file; see [[doc/pxelinux|pxelinux.txt]].)
+
--> default is <tt>-1</tt>, meaning send all cookies.
  
:::This allows an initrd program to determine from which interface the system booted.
+
::This option is "sticky" and is not automatically reset when <!--
 +
--> loading a new configuration file with the <tt>CONFIG</tt> command.
  
 
'''LABEL''' ''label''<br/>
 
'''LABEL''' ''label''<br/>
 
:'''KERNEL''' ''image''
 
:'''KERNEL''' ''image''
 
:'''APPEND''' ''options...''
 
:'''APPEND''' ''options...''
:'''IPAPPEND''' ''flag_val''   [PXELINUX only]
+
:'''SYSAPPEND'''&nbsp;''flag_val''&nbsp;<!--
::Indicates that if "''label''" is entered as the kernel to boot, SYSLINUX should instead boot "''image''", and the specified <tt>APPEND</tt> and <tt>IPAPPEND</tt> options should be used instead of the ones specified in the global section of the file (before the first <tt>LABEL</tt> command.)  The default for "''image''" is the same as "''label''", and if no <tt>APPEND</tt> is given the default is to use the global entry (if any).
+
--><span style=" font-family: monospace; white-space: pre; "><!--
 +
20spaces-->                    &nbsp;</span><tt>[5.10+]</tt>
 +
<!-- :'''SYSAPPEND'''&nbsp;''flag_val''&nbsp;--><!--
 +
--><!--<span style=" font-family: monospace; padding-left: 20ch; ">&nbsp;</span>--><!--
 +
--><!--<tt>[5.10+]</tt> -->
 +
:'''IPAPPEND'''&nbsp;''flag_val''&nbsp;<!--
 +
--><span style=" font-family: monospace; white-space: pre; "><!--
 +
22spaces-->                      &nbsp;</span><tt>[5.10+&nbsp;or&nbsp;PXELINUX&nbsp;only]</tt>
 +
<!-- :'''IPAPPEND'''&nbsp;''flag_val''&nbsp;--><!--
 +
--><!--<span style=" font-family: monospace; padding-left: 22ch; ">&nbsp;</span>--><!--
 +
--><!--<tt>[5.10+&nbsp;or&nbsp;PXELINUX&nbsp;only]</tt> -->
 +
::Indicates that if "''label''" is entered as the kernel to boot, <!--
 +
--> Syslinux should instead boot "''image''", and the specified <tt>APPEND</tt> <!--
 +
--> and <tt>SYSAPPEND</tt> options should be used instead of the ones <!--
 +
--> specified in the global section of the file (before the first <!--
 +
--> <tt>LABEL</tt> command). The default for "''image''" is the same as <!--
 +
--> "''label''", and if no <tt>APPEND</tt> is given the default is to use the <!--
 +
--> global entry (if any).
  
::Starting with version 3.62, the number of LABEL statements is virtually unlimited.
+
::Starting with version 3.62, the number of <tt>LABEL</tt> statements is <!--
 +
--> virtually unlimited.
  
 
::Note that LILO uses the syntax:
 
::Note that LILO uses the syntax:
<pre>
+
{|
 +
|
 
         image = mykernel
 
         image = mykernel
 
           label = mylabel
 
           label = mylabel
 
           append = "myoptions"
 
           append = "myoptions"
</pre>
+
|}
        ... whereas SYSLINUX uses the syntax:
+
::... whereas Syslinux uses the syntax:
<pre>
+
{|
 +
|
 
         label mylabel
 
         label mylabel
 
           kernel mykernel
 
           kernel mykernel
 
           append myoptions
 
           append myoptions
</pre>
+
|}
::'''Note:''' The "''kernel''" doesn't have to be a Linux kernel; it can be a boot sector or a COMBOOT file (see below.)
+
  
::Since version 3.32 label names are no longer mangled into DOS format (for SYSLINUX.)
+
::'''Note''': The "''kernel''" doesn't have to be a Linux kernel; it can <!--
 +
--> be a boot sector <s><small><del>or a COMBOOT file</del></small></s> (see below).
  
::The following commands are available after a <tt>LABEL</tt> statement:
+
::Since version 3.32 label names are no longer mangled into DOS <!--
 +
--> format (for SYSLINUX).
  
::'''LINUX''' ''image''  - Linux kernel image (<tt>default</tt>)
+
:The following commands are available after a <tt>LABEL</tt> statement:
::'''BOOT''' ''image''  - Bootstrap program (<tt>.bs, .bin</tt>)
+
::'''BSS''' ''image''  - BSS image (<tt>.bss</tt>)
+
::'''PXE''' ''image''  - PXE Network Bootstrap Program (<tt>.0</tt>)
+
::'''FDIMAGE''' ''image''  - Floppy disk image (<tt>.img</tt>)
+
::'''COMBOOT''' ''image''  - COMBOOT program (<tt>.com, .cbt</tt>)
+
::'''COM32''' ''image''  - COM32 program (<tt>.c32</tt>)
+
::'''CONFIG''' ''image''  - New configuration file
+
  
:::Using one of these keywords instead of <tt>KERNEL</tt> forces the filetype, regardless of the filename.
+
<div style="white-space:nowrap; ">
 +
:'''LINUX''' ''image''  - Linux kernel image (<tt>default</tt>)
 +
:'''BOOT''' ''image''  - Bootstrap program (<tt>.bs, .bin</tt>)
 +
:'''BSS''' ''image''  - BSS image (<tt>.bss</tt>)
 +
:'''PXE''' ''image''  - PXE Network Bootstrap Program (<tt>.0</tt>)
 +
:'''FDIMAGE''' ''image''  - Floppy disk image (<tt>.img</tt>)
 +
:<s>'''COMBOOT''' ''image''  - COMBOOT program (<tt>.com, .cbt</tt>)</s>
 +
:'''COM32''' ''image''  - COM32 program (<tt>.c32</tt>)
 +
:'''CONFIG''' ''image''  - New configuration file
 +
</div>
  
:::<tt>CONFIG</tt> means restart the boot loader using a different configuration file.
+
::Using one of these keywords instead of <tt>KERNEL</tt> forces the <!--
 +
--> filetype, regardless of the filename.
  
::'''APPEND''' ''-''
+
::<tt>CONFIG</tt> means restart the boot loader using a different <!--
:::Append nothing.  <tt>APPEND</tt> with a single hyphen as argument in a <tt>LABEL</tt> section can be used to override a global <tt>APPEND</tt>.
+
--> configuration file.  The configuration file is read, the <!--
 +
--> working directory is changed (if specified via an <tt>APPEND</tt>), then <!--
 +
--> the configuration file is parsed.
  
::'''LOCALBOOT''' ''type''   [ISOLINUX, PXELINUX]
+
:'''APPEND''' ''-''
:::On PXELINUX, specifying "<tt>LOCALBOOT 0</tt>" instead of a "<tt>KERNEL</tt>" option means invoking this particular label will cause a local disk boot instead of booting a kernel.
+
::Append nothing.  <tt>APPEND</tt> with a single hyphen as argument in a <!--
 +
--> <tt>LABEL</tt> section can be used to override a global <tt>APPEND</tt>.
  
:::The argument 0 means perform a normal boot.  The argument 4 will perform a local boot with the Universal Network Driver Interface (UNDI) driver still resident in memory.  Finally, the argument 5 will perform a local boot with the entire PXE stack, including the UNDI driver, still resident in memory. All other values are undefinedIf you don't know what the UNDI or PXE stacks are, don't worry -- you don't want them, just specify 0.
+
:'''LOCALBOOT'''&nbsp;''type''&nbsp;<!--
 +
--><span style=" font-family: monospace; white-space: pre; "><!--
 +
22spaces-->                      &nbsp;</span><s><small><del><tt>[ISOLINUX,&nbsp;PXELINUX]</tt></del></small></s>
 +
<!-- :'''LOCALBOOT'''&nbsp;''type''&nbsp;--><!--
 +
--><!--<span style=" font-family: monospace; padding-left: 22ch; ">&nbsp;</span>--><!--
 +
--><!--<s><small><del><tt>[ISOLINUX,&nbsp;PXELINUX]</tt></del></small></s> -->
 +
::Attempt a different local boot method.  The special value -1 <!--
 +
--> causes the boot loader to report failure to the BIOS, which, on <!--
 +
--> recent BIOSes, should mean that the next boot device in the <!--
 +
--> boot sequence should be activatedValues other than those <!--
 +
--> documented may produce undesired results.
  
:::On ISOLINUX, the "''type''" specifies the local drive number to boot from; 0x00 is the primary floppy drive and 0x80 is the primary hard driveThe special value -1 causes ISOLINUX to report failure to the BIOS, which, on recent BIOSes, should mean that the next boot device in the boot sequence should be activated.
+
<!-- v.3.72: --><!--
 +
--><!--::On PXELINUX, specifying "<tt>LOCALBOOT 0</tt>" instead of a "<tt>KERNEL</tt>" --><!--
 +
--><!-- option means invoking this particular label will cause a local --><!--
 +
--><!-- disk boot instead of booting a kernel. --><!--
 +
--><!--      -->
 +
::On PXELINUX, "''type''" 0 means perform a normal boot.  "''type''" 4 <!--
 +
--> will perform a local boot with the Universal Network Driver <!--
 +
--> Interface (UNDI) driver still resident in memoryFinally, <!--
 +
--> "''type''" 5 will perform a local boot with the entire PXE <!--
 +
--> stack, including the UNDI driver, still resident in memory. <!--
 +
--> All other values are undefined.  If you don't know what the <!--
 +
--> UNDI or PXE stacks are, don't worry -- you don't want them, <!--
 +
--> just specify 0.
  
::'''INITRD''' ''initrd_file''
+
::On ISOLINUX, the "''type''" specifies the local drive number to <!--
:::Starting with version 3.71, an initrd can be specified in a separate statement (<tt>INITRD</tt>) instead of as part of the <tt>APPEND</tt> statement; this functionally appends "<tt>initrd=initrd_file</tt>" to the kernel command line.
+
--> boot from; 0x00 is the primary floppy drive and 0x80 is the <!--
 +
--> primary hard drive. <!--
 +
--><!--        --><!--
 +
--><!-- v.3.72: (This paragraph was mainly moved upwards) --><!--
 +
--><!--  The special value -1 causes ISOLINUX to --><!--
 +
--><!-- report failure to the BIOS, which, on recent BIOSes, should --><!--
 +
--><!-- mean that the next boot device in the boot sequence should be --><!--
 +
--><!-- activated. --><!--
 +
--><!--        -->
 +
 
 +
:'''INITRD''' ''initrd_file''
 +
::Starting with version 3.71, an initrd can be specified in a <!--
 +
--> separate statement (<tt>INITRD</tt>) instead of as part of the <tt>APPEND</tt> <!--
 +
--> statement; this functionally appends "<tt>initrd=initrd_file</tt>" to <!--
 +
--> the kernel command line.
 +
 
 +
::It supports multiple filenames separated by commas. <!--
 +
--> This is mostly useful for initramfs, which can be composed of <!--
 +
--> multiple separate cpio or cpio.gz archives. <!--
 +
--> Note: all files except the last one are zero-padded to a <!--
 +
--> 4K page boundary.  This should not affect initramfs.
  
 
'''IMPLICIT''' ''flag_val''
 
'''IMPLICIT''' ''flag_val''
::If ''flag_val'' is 0, do not load a kernel image unless it has been explicitly named in a <tt>LABEL</tt> statement.  The default is 1.
+
::If ''flag_val'' is 0, do not load a kernel image unless it has been <!--
 +
--> explicitly named in a <tt>LABEL</tt> statement.  The default is 1.
  
 
'''ALLOWOPTIONS''' ''flag_val''
 
'''ALLOWOPTIONS''' ''flag_val''
::If ''flag_val'' is 0, the user is not allowed to specify any arguments on the kernel command line.  The only options recognized are those specified in an <tt>APPEND</tt> statement.  The default is 1.
+
::If ''flag_val'' is 0, the user is not allowed to specify any <!--
 +
--> arguments on the kernel command line.  The only options <!--
 +
--> recognized are those specified in an <tt>APPEND</tt> statement.  The <!--
 +
--> default is 1.
  
 
'''TIMEOUT''' ''timeout''
 
'''TIMEOUT''' ''timeout''
::Indicates how long to wait at the <tt>boot:</tt> prompt until booting automatically, in units of 1/10 s.  The timeout is cancelled as soon as the user types anything on the keyboard, the assumption being that the user will complete the command line already begun.  A timeout of zero will disable the timeout completely, this is also the default.
+
::Indicates how long to wait at the <tt>boot:</tt> prompt until booting <!--
 +
--> automatically, in units of 1/10 s.  The timeout is cancelled as <!--
 +
--> soon as the user types anything on the keyboard, the assumption <!--
 +
--> being that the user will complete the command line already <!--
 +
--> begun.  A ''timeout'' of zero will disable the timeout completely, <!--
 +
--> this is also the default.
  
 
'''TOTALTIMEOUT''' ''timeout''
 
'''TOTALTIMEOUT''' ''timeout''
::Indicates how long to wait until booting automatically, in units of 1/10 s.  This timeout is <u>''not''</u> cancelled by user input, and can thus be used to deal with serial port glitches or "the user walked away" type situations.  A timeout of zero will disable the timeout completely, this is also the default.
+
::Indicates how long to wait until booting automatically, in <!--
 +
--> units of 1/10 s.  This timeout is <u>''not''</u> cancelled by user <!--
 +
--> input, and can thus be used to deal with serial port glitches <!--
 +
--> or "the user walked away" type situations.  A ''timeout'' of zero <!--
 +
--> will disable the timeout completely, this is also the default.
  
::Both <tt>TIMEOUT</tt> and <tt>TOTALTIMEOUT</tt> can be used together, for example:
+
::Both <tt>TIMEOUT</tt> and <tt>TOTALTIMEOUT</tt> can be used together, for <!--
<pre>
+
--> example:
# Wait 5 seconds unless the user types something, but
+
{|
# always boot after 15 minutes.
+
|
TIMEOUT 50
+
# Wait 5 seconds unless the user types something, but
TOTALTIMEOUT 9000
+
# always boot after 15 minutes.
</pre>
+
TIMEOUT 50
 +
TOTALTIMEOUT 9000
 +
|}
  
 
'''ONTIMEOUT''' ''kernel options...''
 
'''ONTIMEOUT''' ''kernel options...''
::Sets the command line invoked on a timeout.  Normally this is the same thing as invoked by "<tt>DEFAULT</tt>".  If this is specified, then "<tt>DEFAULT</tt>" is used only if the user presses <Enter> to boot.
+
::Sets the command line invoked on a timeout.  Normally this is <!--
 +
--> the same thing as invoked by "<tt>DEFAULT</tt>".  If this is specified, <!--
 +
--> then "<tt>DEFAULT</tt>" is used only if the user presses <Enter> to <!--
 +
--> boot.
  
 
'''ONERROR''' ''kernel options...''
 
'''ONERROR''' ''kernel options...''
::If a kernel image is not found (either due to it not existing, or because <tt>IMPLICIT</tt> is set), run the specified command.  The faulty command line is appended to the specified options, so if the <tt>ONERROR</tt> directive reads as:
+
::If a kernel image is not found (either due to it not existing, <!--
 +
--> or because <tt>IMPLICIT</tt> is set), run the specified command.  The <!--
 +
--> faulty command line is appended to the specified options, so <!--
 +
--> if the <tt>ONERROR</tt> directive reads as:
  
 
:::<tt>ONERROR xyzzy plugh</tt>
 
:::<tt>ONERROR xyzzy plugh</tt>
Line 212: Line 519:
 
:::<tt>foo bar baz</tt>
 
:::<tt>foo bar baz</tt>
  
::... SYSLINUX will execute the following as if entered by the user:
+
::... Syslinux will execute the following as if entered by the user:
  
 
:::<tt>xyzzy plugh foo bar baz</tt>
 
:::<tt>xyzzy plugh foo bar baz</tt>
  
'''SERIAL''' ''port [[baudrate] flowcontrol]''
+
'''SERIAL''' ''port [baudrate [flowcontrol]]''
::Enables a serial port to act as the console.  "''port''" is a number (0 = <tt>/dev/ttyS0</tt> = COM1, etc.) or an I/O port address (e.g. <tt>0x3F8</tt>); if "baudrate" is omitted, the baud rate defaults to 9600 bps.  The serial parameters are hardcoded to be 8 bits, no parity, 1 stop bit.
+
::Enables a serial port to act as the console.  "''port''" is a <!--
 +
--> number (0 = <tt>/dev/ttyS0</tt> = COM1, etc.) or an I/O port address <!--
 +
--> (e.g. <tt>0x3F8</tt>); if "''baudrate''" is omitted, the baud rate defaults <!--
 +
--> to 9600 bps.  The serial parameters are hardcoded to be 8 <!--
 +
--> bits, no parity, 1 stop bit.
  
 
::"''flowcontrol''" is a combination of the following bits:
 
::"''flowcontrol''" is a combination of the following bits:
:::0x001 - Assert DTR
+
 
:::0x002 - Assert RTS
+
{|
:::0x010 - Wait for CTS assertion
+
|
:::0x020 - Wait for DSR assertion
+
    0x001 - Assert DTR
:::0x040 - Wait for RI assertion
+
    0x002 - Assert RTS
:::0x080 - Wait for DCD assertion
+
    0x008 - Enable interrupts
:::0x100 - Ignore input unless CTS asserted
+
    0x010 - Wait for CTS assertion
:::0x200 - Ignore input unless DSR asserted
+
    0x020 - Wait for DSR assertion
:::0x400 - Ignore input unless RI asserted
+
    0x040 - Wait for RI assertion
:::0x800 - Ignore input unless DCD asserted
+
    0x080 - Wait for DCD assertion
 +
    0x100 - Ignore input unless CTS asserted
 +
    0x200 - Ignore input unless DSR asserted
 +
    0x400 - Ignore input unless RI asserted
 +
    0x800 - Ignore input unless DCD asserted
 +
|}
  
 
::All other bits are reserved.
 
::All other bits are reserved.
Line 235: Line 551:
 
::Typical values are:
 
::Typical values are:
  
:::&nbsp;&nbsp;&nbsp;&nbsp;0 - No flow control (default)
+
{|
:::0x303 - Null modem cable detect
+
|
:::0x013 - RTS/CTS flow control
+
        0 - No flow control (default)
:::0x813 - RTS/CTS flow control, modem input
+
    0x303 - Null modem cable detect
:::0x023 - DTR/DSR flow control
+
    0x013 - RTS/CTS flow control
:::0x083 - DTR/DCD flow control
+
    0x813 - RTS/CTS flow control, modem input
 +
    0x023 - DTR/DSR flow control
 +
    0x083 - DTR/DCD flow control
 +
|}
 +
 
 +
::For the <tt>SERIAL</tt> directive to be guaranteed to work properly, it <!--
 +
--> should be the first directive in the configuration file.
 +
 
 +
::'''NOTE''': "''port''" values from 0 to 3 means the first four serial <!--
 +
--> ports detected by the BIOS.  They may or may not correspond to <!--
 +
--> the legacy port values 0x3F8, 0x2F8, 0x3E8, 0x2E8.
 +
 
 +
::Enabling interrupts (setting the 0x008 bit) may give better <!--
 +
--> responsiveness without setting the <tt>NOHALT</tt> option, but could <!--
 +
--> potentially cause problems with buggy BIOSes.
  
::For the <tt>SERIAL</tt> directive to be guaranteed to work properly, it should be the first directive in the configuration file.
+
::This option is "sticky" and is not automatically reset when <!--
 +
--> loading a new configuration file with the <tt>CONFIG</tt> command.
  
::'''NOTE:''' "''port''" values from 0 to 3 means the first four serial ports detected by the BIOS.  They may or may not correspond to the legacy port values 0x3F8, 0x2F8, 0x3E8, 0x2E8.
+
'''NOHALT''' ''flag_val''
 +
::If ''flag_val'' is 1, don't halt the processor while idle. <!--
 +
--> Halting the processor while idle significantly reduces the <!--
 +
--> power consumption, but can cause poor responsiveness to the <!--
 +
--> serial console, especially when using scripts to drive the <!--
 +
--> serial console, as opposed to human interaction.
  
 
'''CONSOLE''' ''flag_val''
 
'''CONSOLE''' ''flag_val''
::If flag_val is 0, disable output to the normal video console.
+
::If ''flag_val'' is 0, disable output to the normal video console.
::If flag_val is 1, enable output to the video console (this is the default.)
+
::If ''flag_val'' is 1, enable output to the video console (this is the default).
  
::Some BIOSes try to forward this to the serial console and sometimes make a total mess thereof, so this option lets you disable the video console on these systems.
+
::Some BIOSes try to forward this to the serial console and <!--
 +
--> sometimes make a total mess thereof, so this option lets you <!--
 +
--> disable the video console on these systems.
  
 
'''FONT''' ''filename''
 
'''FONT''' ''filename''
::Load a font in <tt>.psf</tt> format before displaying any output (except the copyright line, which is output as <tt>ldlinux.sys</tt> itself is loaded.SYSLINUX only loads the font onto the video card; if the <tt>.psf</tt> file contains a Unicode table it is ignored.  This only works on EGA and VGA cards; hopefully it should do nothing on others.
+
::Load a font in <tt>.psf</tt> format before displaying any output <!--
 +
--> (except the copyright line, which is output as <tt>ldlinux.sys</tt> <!--
 +
--> itself is loaded). Syslinux only loads the font onto the <!--
 +
--> video card; if the <tt>.psf</tt> file contains a Unicode table it is <!--
 +
--> ignored.  This only works on EGA and VGA cards; hopefully it <!--
 +
--> should do nothing on others.
  
 
'''KBDMAP''' ''keymap''
 
'''KBDMAP''' ''keymap''
::Install a simple keyboard map.  The keyboard remapper used is <u>''very''</u> simplistic (it simply remaps the keycodes received from the BIOS, which means that only the key combinations relevant in the default layout -- usually U.S. English -- can be mapped) but should at least help people with AZERTY keyboard layout and the locations of = and , (two special characters used heavily on the Linux kernel command line.)
+
::Install a simple keyboard map.  The keyboard remapper used is <!--
 +
--> <u>''very''</u> simplistic (it simply remaps the keycodes received from <!--
 +
--> the BIOS, which means that only the key combinations relevant <!--
 +
--> in the default layout -- usually U.S. English -- can be <!--
 +
--> mapped) but should at least help people with AZERTY keyboard <!--
 +
--> layout and the locations of "<tt>=</tt>" and "<tt>,</tt>" (two special characters <!--
 +
--> used heavily on the Linux kernel command line).
  
::The included program <tt>keytab-lilo.pl</tt> from the LILO distribution can be used to create such keymaps.  The file [[doc/keytab-lilo|keytab-lilo.txt]] contains the documentation for this program.
+
::The included program <tt>keytab-lilo.pl</tt> from the LILO distribution <!--
 +
--> can be used to create such keymaps.  The file [[doc/keytab-lilo|keytab-lilo.txt]] <!--
 +
--> contains the documentation for this program.
  
 
'''DISPLAY''' ''filename''
 
'''DISPLAY''' ''filename''
::Displays the indicated file on the screen at boot time (before the <tt>boot:</tt> prompt, if displayed).  Please see the section below on <tt>DISPLAY</tt> files.
+
::Displays the indicated file on the screen at boot time (before <!--
 +
--> the <tt>boot:</tt> prompt, if displayed).  Please see the section below <!--
 +
--> on <tt>DISPLAY</tt> files.
  
::'''NOTE:''' If the file is missing, this option is simply ignored.
+
::'''NOTE''': If the file is missing, this option is simply ignored.
  
 
'''SAY''' ''message''
 
'''SAY''' ''message''
::Prints the message on the screen.
+
::Prints the ''message'' on the screen.
  
 
'''PROMPT''' ''flag_val''
 
'''PROMPT''' ''flag_val''
::If ''flag_val'' is 0, display the <tt>boot:</tt> prompt only if the Shift or Alt key is pressed, or Caps Lock or Scroll lock is set (this is the default).  If ''flag_val'' is 1, always display the <tt>boot:</tt> prompt.
+
::If ''flag_val'' is 0, display the <tt>boot:</tt> prompt only if the Shift or Alt <!--
 +
--> key is pressed, or Caps Lock or Scroll Lock is set (this is the <!--
 +
--> default).  If ''flag_val'' is 1, always display the <tt>boot:</tt> prompt.
  
 
'''NOESCAPE''' ''flag_val''
 
'''NOESCAPE''' ''flag_val''
::If flag_val is set to 1, ignore the Shift/Alt/Caps Lock/Scroll Lock escapes.  Use this (together with <tt>PROMPT 0</tt>) to force the default boot alternative.
+
::If ''flag_val'' is set to 1, ignore the Shift/Alt/Caps&nbsp;Lock/Scroll&nbsp;<!--
 +
--> Lock escapes.  Use this (together with <tt>PROMPT 0</tt>) to force the <!--
 +
--> default boot alternative.
  
 
'''NOCOMPLETE''' ''flag_val''
 
'''NOCOMPLETE''' ''flag_val''
::If ''flag_val'' is set to 1, the Tab key does not display labels at the <tt>boot:</tt> prompt.
+
::If ''flag_val'' is set to 1, the Tab key does not display labels <!--
 +
--> at the <tt>boot:</tt> prompt.
  
 
'''F1''' ''filename''<br/>
 
'''F1''' ''filename''<br/>
Line 283: Line 641:
 
'''F10''' ''filename''<br/>
 
'''F10''' ''filename''<br/>
 
'''F11''' ''filename''<br/>
 
'''F11''' ''filename''<br/>
'''F11''' ''filename''<br/>
+
'''F12''' ''filename''<br/>
::Displays the indicated file on the screen when a function key is pressed at the <tt>boot:</tt> prompt.  This can be used to implement pre-boot online help (presumably for the kernel command line options.)  Please see the section below on <tt>DISPLAY</tt> files.
+
::Displays the indicated file on the screen when a function key is <!--
 +
--> pressed at the <tt>boot:</tt> prompt.  This can be used to implement <!--
 +
--> pre-boot online help (presumably for the kernel command line <!--
 +
--> options). Please see the section below on <tt>DISPLAY</tt> files.
  
::When using the serial console, press ''<Ctrl-F><digit>'' to get to the help screens, e.g. ''<Ctrl-F><2>'' to get to the <tt>F2</tt> screen.
+
::When using the serial console, press ''<Ctrl-F><digit>'' to get to <!--
::For <tt>F10-F12</tt>, hit ''<Ctrl-F><A>, <Ctrl-F>B, <Ctrl-F>C'''.  For compatiblity with earlier versions, <tt>F10</tt> can also be entered as ''<Ctrl-F>0''.
+
--> the help screens, e.g. ''<Ctrl-F><2>'' to get to the <tt>F2</tt> screen.
 +
::For <tt>F10-F12</tt>, hit ''<Ctrl-F>&lt;A&gt;, <Ctrl-F>&lt;B&gt;, <Ctrl-F>&lt;C&gt;''.  For <!--
 +
--> compatibility with earlier versions, <tt>F10</tt> can also be entered as <!--
 +
--> ''<Ctrl-F><0>''.
  
 +
'''PATH''' ''path''
 +
::Specify a colon-separated (':') list of directories to search <!--
 +
--> when attempting to load modules. This directive is useful for <!--
 +
--> specifying the directories containing the lib*.c32 library <!--
 +
--> files as other modules may be dependent on these files, but <!--
 +
--> may not reside in the same directory. The list of directories <!--
 +
--> is searched in order. Please see the section below on <!--
 +
--> [[#PATH_RULES|PATH RULES]].
 +
 +
<br />
 
Blank lines are ignored.
 
Blank lines are ignored.
  
Note that the configuration file is not completely decoded.  Syntax different from the one described above may still work correctly in this version of SYSLINUX, but may break in a future one.
+
Note that the configuration file is not completely decoded.  Syntax  
 +
different from the one described above may still work correctly in this  
 +
version of Syslinux, but may break in a future one.
 +
 
  
=DISPLAY FILE FORMAT=
+
== DISPLAY FILE FORMAT ==
  
DISPLAY and function-key help files are text files in either DOS or UNIX format (with or without <CR>).  In addition, the following special codes are interpreted:
+
DISPLAY and function-key help files are text files in either DOS or UNIX  
 +
format (with or without <CR>).  In addition, the following special codes  
 +
are interpreted:
  
 
'''< FF >'''<br/>
 
'''< FF >'''<br/>
 
''< FF > = <Ctrl-L> = ASCII 12''<br/>
 
''< FF > = <Ctrl-L> = ASCII 12''<br/>
::Clear the screen, home the cursor.  Note that the screen is filled with the current display color.
+
::Clear the screen, home the cursor.  Note that the screen is <!--
 +
--> filled with the current display color.
  
'''< SI ><bg><fg>'''<br/>
+
'''< SI >'''''<bg><fg>''<br/>
 
''< SI > = <Ctrl-O> = ASCII 15''<br/>
 
''< SI > = <Ctrl-O> = ASCII 15''<br/>
::Set the display colors to the specified background and foreground colors, where ''<bg>'' and ''<fg>'' are hex digits, corresponding to the standard PC display attributes:
+
::Set the display colors to the specified background and <!--
<pre>
+
--> foreground colors, where ''<bg>'' and ''<fg>'' are hex digits, <!--
        0 = black               8 = dark grey
+
--> corresponding to the standard PC display attributes:
        1 = dark blue           9 = bright blue
+
{|
        2 = dark green         a = bright green
+
|
        3 = dark cyan           b = bright cyan
+
0 = black       8 = dark grey
        4 = dark red           c = bright red
+
1 = dark blue   9 = bright blue
        5 = dark purple         d = bright purple
+
2 = dark green a = bright green
        6 = brown               e = yellow
+
3 = dark cyan   b = bright cyan
        7 = light grey         f = white
+
4 = dark red   c = bright red
</pre>
+
5 = dark purple d = bright purple
::Picking a bright color (8-f) for the background results in the corresponding dark color (0-7), with the foreground flashing.
+
6 = brown       e = yellow
 +
7 = light grey f = white
 +
|}
 +
::Picking a bright color (8-f) for the background results in the <!--
 +
--> corresponding dark color (0-7), with the foreground flashing.
  
 
::Colors are not visible over the serial console.
 
::Colors are not visible over the serial console.
Line 320: Line 704:
 
'''< CAN >'''''filename<newline>''<br/>
 
'''< CAN >'''''filename<newline>''<br/>
 
''< CAN > = <Ctrl-X> = ASCII 24''<br/>
 
''< CAN > = <Ctrl-X> = ASCII 24''<br/>
::If a VGA display is present, enter graphics mode and display the graphic included in the specified file.  The file format is an ad hoc format called LSS16; the included Perl program "<tt>ppmtolss16</tt>" can be used to produce these images.  This Perl program also includes the file format specification.
+
::If a VGA display is present, enter graphics mode and display <!--
 +
--> the graphic included in the specified file.  The file format <!--
 +
--> is an ad hoc format called LSS16; the included Perl program <!--
 +
--> "<tt>ppmtolss16</tt>" can be used to produce these images.  This Perl <!--
 +
--> program also includes the file format specification.
  
::The image is displayed in 640x480 16-color mode.  Once in graphics mode, the display attributes (set by ''<SI>'' code sequences) work slightly differently: the background color is ignored, and the foreground colors are the 16 colors specified in the image file.  For that reason, ppmtolss16 allows you to specify that certain colors should be assigned to specific color indices.
+
::The image is displayed in 640x480 16-color mode.  Once in <!--
 +
--> graphics mode, the display attributes (set by ''<SI>'' code <!--
 +
--> sequences) work slightly differently: the background color is <!--
 +
--> ignored, and the foreground colors are the 16 colors specified <!--
 +
--> in the image file.  For that reason, ppmtolss16 allows you to <!--
 +
--> specify that certain colors should be assigned to specific <!--
 +
--> color indices.
  
::Color indices 0 and 7, in particular, should be chosen with care: 0 is the background color, and 7 is the color used for the text printed by SYSLINUX itself.
+
::Color indices 0 and 7, in particular, should be chosen with <!--
 +
--> care: 0 is the background color, and 7 is the color used for <!--
 +
--> the text printed by Syslinux itself.
  
 
'''< EM >'''<br/>
 
'''< EM >'''<br/>
Line 332: Line 728:
 
'''< DLE > .. < ETB >'''<br/>
 
'''< DLE > .. < ETB >'''<br/>
 
''<Ctrl-P>..<Ctrl-W> = ASCII 16-23''<br/>
 
''<Ctrl-P>..<Ctrl-W> = ASCII 16-23''<br/>
::These codes can be used to select which modes to print a certain part of the message file in.  Each of these control characters select a specific set of modes (text screen, graphics screen, serial port) for which the output is actually displayed:
+
::These codes can be used to select which modes to print a <!--
<pre>
+
--> certain part of the message file in.  Each of these control <!--
Character Text Graph Serial
+
--> characters select a specific set of modes (text screen, <!--
------------------------------------------------------
+
--> graphics screen, serial port) for which the output is actually <!--
<DLE> = <Ctrl-P> = ASCII 16 No No No
+
--> displayed:
<DC1> = <Ctrl-Q> = ASCII 17 Yes No No
+
{|
<DC2> = <Ctrl-R> = ASCII 18 No Yes No
+
|
<DC3> = <Ctrl-S> = ASCII 19 Yes Yes No
+
Character Text Graph Serial
<DC4> = <Ctrl-T> = ASCII 20 No No Yes
+
------------------------------------------------------
<NAK> = <Ctrl-U> = ASCII 21 Yes No Yes
+
<DLE> = <Ctrl-P> = ASCII 16 No No No
<SYN> = <Ctrl-V> = ASCII 22 No Yes Yes
+
<DC1> = <Ctrl-Q> = ASCII 17 Yes No No
<ETB> = <Ctrl-W> = ASCII 23 Yes Yes Yes
+
<DC2> = <Ctrl-R> = ASCII 18 No Yes No
</pre>
+
<DC3> = <Ctrl-S> = ASCII 19 Yes Yes No
 +
<DC4> = <Ctrl-T> = ASCII 20 No No Yes
 +
<NAK> = <Ctrl-U> = ASCII 21 Yes No Yes
 +
<SYN> = <Ctrl-V> = ASCII 22 No Yes Yes
 +
<ETB> = <Ctrl-W> = ASCII 23 Yes Yes Yes
 +
|}
 
::For example:
 
::For example:
<pre>
+
{|
<DC1>Text mode<DC2>Graphics mode<DC4>Serial port<ETB>
+
|
</pre>
+
<DC1>Text mode<DC2>Graphics mode<DC4>Serial port<ETB>
 +
|}
 
::... will actually print out which mode the console is in!
 
::... will actually print out which mode the console is in!
  
Line 360: Line 762:
  
  
=COMMAND LINE KEYSTROKES=
+
== COMMAND LINE KEYSTROKES ==
  
The command line prompt supports the following keystrokes:
+
The command line prompt supports the following [[Cli#Keystrokes|keystrokes]]:
 +
{|
 +
|
 +
''<Enter>'' boot specified command line
 +
''<BackSpace>'' erase one character
 +
''<Ctrl-U>'' erase the whole line
 +
''<Ctrl-V>'' display the current Syslinux version
 +
''<Ctrl-W>'' erase one word
 +
''<Ctrl-X>'' force text mode
 +
''<Tab>'' list matching labels
 +
''<F1>..<F12>'' help screens (if configured)
 +
''<Ctrl-F><digit>'' equivalent to F1..F10
 +
''<Ctrl-C>'' interrupt boot in progress
 +
''<Esc>'' interrupt boot in progress
 +
''<Ctrl-N>'' display network information (PXELINUX only)
 +
|}
  
''<Enter>'' boot specified command line
+
== OTHER OPERATING SYSTEMS ==
''<BackSpace>'' erase one character
+
<span id="COMBOOT_IMAGES_AND_OTHER_OPERATING_SYSTEMS"></span>
''<Ctrl-U>'' erase the whole line
+
''<Ctrl-V>'' display the current SYSLINUX version
+
''<Ctrl-W>'' erase one word
+
''<Ctrl-X>'' force text mode
+
''<F1>..<F10>'' help screens (if configured)
+
''<Ctrl-F><digit>'' equivalent to F1..F10
+
''<Ctrl-C>'' interrupt boot in progress
+
''<Esc>'' interrupt boot in progress
+
  
 +
This version of Syslinux supports chain loading of other operating
 +
systems (such as MS-DOS and its derivatives, including Windows 95/98)<!--
 +
--><!--, as well as COMBOOT-style standalone executables (a subset of DOS <tt>.COM</tt> --><!--
 +
--><!--files; see separate section below)-->.
  
=COMBOOT IMAGES AND OTHER OPERATING SYSTEMS=
+
Chain loading requires the boot sector of the foreign operating system  
 
+
to be stored in a file in the root directory of the filesystem.  
This version of SYSLINUX supports chain loading of other operating systems (such as MS-DOS and its derivatives, including Windows 95/98), as well as COMBOOT-style standalone executables (a subset of DOS <tt>.COM</tt> files; see separate section below.)
+
Because neither Linux kernels, nor boot sector images<!--, nor COMBOOT files--> have reliable  
 
+
magic numbers, Syslinux will look at the file extension.  
Chain loading requires the boot sector of the foreign operating system to be stored in a file in the root directory of the filesystem. Because neither Linux kernels, boot sector images, nor COMBOOT files have reliable magic numbers, SYSLINUX will look at the file extension. The following extensions are recognized (case insensitive):
+
The following extensions are recognized (case insensitive):
<pre>
+
<!-- Do _not_ use "pre" tags here -->
   none or other Linux kernel image
+
{|
 +
|
 +
   none or other Linux kernel image
 
   .0 PXE bootstrap program (NBP) [PXELINUX only]
 
   .0 PXE bootstrap program (NBP) [PXELINUX only]
 
   .bin "CD boot sector" [ISOLINUX only]
 
   .bin "CD boot sector" [ISOLINUX only]
 
   .bs Boot sector [SYSLINUX only]
 
   .bs Boot sector [SYSLINUX only]
 
   .bss Boot sector, DOS superblock will be patched in [SYSLINUX only]
 
   .bss Boot sector, DOS superblock will be patched in [SYSLINUX only]
   .c32 COM32 image (32-bit COMBOOT)
+
   .c32 COM32 image (32-bit <s><small><del>COMBOOT</del></small></s> ELF)
   .cbt COMBOOT image (not runnable from DOS)
+
   <small>.cbt COMBOOT image (not runnable from DOS) [-4.xx]</small>
   .com COMBOOT image (runnable from DOS)
+
   <small>.com COMBOOT image (runnable from DOS) [-4.xx]</small>
 
   .img Disk image [ISOLINUX only]
 
   .img Disk image [ISOLINUX only]
</pre>
+
|}
For filenames given on the command line, SYSLINUX will search for the file by adding extensions in the order listed above if the plain filename is not found.  Filenames in <tt>KERNEL</tt> statements must be fully qualified.
+
<!--  -->
 +
For filenames given on the command line, Syslinux will search for the  
 +
file by adding extensions in the order listed above if the plain  
 +
filename is not found.  Filenames in <tt>KERNEL</tt> statements must be fully  
 +
qualified.
  
If this is specified with one of the keywords <tt>LINUX, BOOT, BSS, FDIMAGE, COMBOOT, COM32</tt>, or <tt>CONFIG</tt> instead of <tt>KERNEL</tt>, the filetype is considered to be the one specified regardless of the filename.
+
If this is specified with one of the keywords <tt>LINUX, BOOT, BSS,  
 +
FDIMAGE, <small>COMBOOT,</small> COM32</tt>, or <tt>CONFIG</tt> instead of <tt>KERNEL</tt>, the filetype is  
 +
considered to be the one specified regardless of the filename.
  
  
=BOOTING DOS (OR OTHER SIMILAR OPERATING SYSTEMS)=
+
== BOOTING DOS (OR OTHER SIMILAR OPERATING SYSTEMS) ==
  
 
This section applies to SYSLINUX only, not to PXELINUX or ISOLINUX.
 
This section applies to SYSLINUX only, not to PXELINUX or ISOLINUX.
 
See [[doc/isolinux|isolinux.txt]] for an equivalent procedure for ISOLINUX.
 
See [[doc/isolinux|isolinux.txt]] for an equivalent procedure for ISOLINUX.
  
This is the recommended procedure for creating a SYSLINUX disk that can boot either DOS or Linux.  This example assumes the drive is A: in DOS and <tt>/dev/fd0</tt> in Linux; for other drives, substitute the appropriate drive designator.
+
This is the recommended procedure for creating a SYSLINUX disk that  
 +
can boot either DOS or Linux.  This example assumes the drive is A: in  
 +
DOS and <tt>/dev/fd0</tt> in Linux; for other drives, substitute the  
 +
appropriate drive designator.
  
==Linux procedure==
+
=== Linux procedure ===
  
 
'''1.'''  
 
'''1.'''  
::Make a DOS bootable disk.  This can be done either by specifying the <tt>/s</tt> option when formatting the disk in DOS, or by running the DOS command <tt>SYS</tt> (this can be done under DOSEMU if DOSEMU has direct device access to the relevant drive):
+
::Make a DOS bootable disk.  This can be done either by specifying <!--
 +
--> the <tt>/s</tt> option when formatting the disk in DOS, or by running the <!--
 +
--> DOS command <tt>SYS</tt> (this can be done under DOSEMU if DOSEMU has <!--
 +
--> direct device access to the relevant drive):
  
:::<tt>format a: /s</tt>
+
:::::<span style="white-space:nowrap;"><code>format a: /s</code></span>
 
::or
 
::or
:::<tt>sys a:</tt>
+
:::::<span style="white-space:nowrap;"><code>sys a:</code></span>
  
 
'''2.'''
 
'''2.'''
 
::Boot Linux.  Copy the DOS boot sector from the disk into a file:
 
::Boot Linux.  Copy the DOS boot sector from the disk into a file:
  
:::<tt>dd if=/dev/fd0 of=dos.bss bs=512 count=1</tt>
+
:::::<span style="white-space:nowrap;"><code>dd if=/dev/fd0 of=dos.bss bs=512 count=1</code></span>
  
 
'''3.'''
 
'''3.'''
 
::Run SYSLINUX on the disk:
 
::Run SYSLINUX on the disk:
  
:::<tt>syslinux /dev/fd0</tt>
+
:::::<span style="white-space:nowrap;"><code>syslinux -i /dev/fd0</code></span>
  
 
'''4.'''
 
'''4.'''
::Mount the disk and copy the DOS boot sector file to it.  The file <u>''must''</u> have extension <tt>.bss</tt>:
+
::Mount the disk and copy the DOS boot sector file to it.  The file <!--
 +
--> <u>''must''</u> have extension <tt>.bss</tt>:
  
:::<tt>mount -t msdos /dev/fd0 /mnt</tt>
+
:::::<span style="white-space:nowrap;"><code>mount -t msdos /dev/fd0 /mnt</code></span>
:::<tt>cp dos.bss /mnt</tt>
+
:::::<span style="white-space:nowrap;"><code>cp dos.bss /mnt</code></span>
  
 
'''5.'''
 
'''5.'''
::Copy the Linux kernel image(s), initrd(s), etc to the disk, and create/edit <tt>syslinux.cfg</tt> and help files if desired:
+
::Copy the Linux kernel image(s), initrd(s), etc to the disk, and <!--
 +
--> create/edit <tt>syslinux.cfg</tt> and help files if desired:
  
:::<tt>cp vmlinux /mnt</tt>
+
:::::<span style="white-space:nowrap;"><code>cp vmlinux /mnt</code></span>
:::<tt>cp initrd.gz /mnt</tt>
+
:::::<span style="white-space:nowrap;"><code>cp initrd.gz /mnt</code></span>
  
 
'''6.'''
 
'''6.'''
::Unmount the disk (if applicable.)
+
::Unmount the disk (if applicable).
  
:::<tt>umount /mnt</tt>
+
:::::<span style="white-space:nowrap;"><code>umount /mnt</code></span>
  
==DOS/Windows procedure==
+
=== DOS/Windows procedure ===
  
To make this installation in DOS only, you need the utility <tt>copybs.com</tt> (included with SYSLINUX) as well as the syslinux.com installer.  If you are on an WinNT-based system (WinNT, Win2k, WinXP or later), use <tt>syslinux.exe</tt> instead.
+
To make this installation in DOS only, you need the utility <tt>copybs.com</tt>  
 +
(included with Syslinux) as well as the <tt>syslinux.com</tt> installer.  If  
 +
you are on a WinNT-based system (WinNT, Win2k, WinXP or later), use  
 +
<tt>syslinux.exe</tt> instead.
  
 
'''1.'''
 
'''1.'''
::Make a DOS bootable disk.  This can be done either by specifying the <tt>/s</tt> option when formatting the disk in DOS, or by running the DOS command <tt>SYS</tt>:
+
::Make a DOS bootable disk.  This can be done either by specifying <!--
 +
--> the <tt>/s</tt> option when formatting the disk in DOS, or by running the <!--
 +
--> DOS command <tt>SYS</tt>:
  
:::<tt>format a: /s</tt>
+
:::::<span style="white-space:nowrap;"><code>format a: /s</code></span>
 
::or
 
::or
:::<tt>sys a:</tt>
+
:::::<span style="white-space:nowrap;"><code>sys a:</code></span>
  
 
'''2.'''
 
'''2.'''
::Copy the DOS boot sector from the disk into a file.  The file <u>''must''</u> have extension <tt>.bss</tt>:
+
::Copy the DOS boot sector from the disk into a file.  The file <!--
 +
--> <u>''must''</u> have extension <tt>.bss</tt>:
  
:::<tt>copybs a: a:dos.bss</tt>
+
:::::<span style="white-space:nowrap;"><code>copybs a: a:dos.bss</code></span>
  
 
'''3.'''
 
'''3.'''
 
::Run SYSLINUX on the disk:
 
::Run SYSLINUX on the disk:
  
:::<tt>syslinux a:</tt>
+
:::::<span style="white-space:nowrap;"><code>syslinux -i a:</code></span>
  
 
'''4.'''
 
'''4.'''
::Copy the Linux kernel image(s), initrd(s), etc to the disk, and create/edit <tt>syslinux.cfg</tt> and help files if desired:
+
::Copy the Linux kernel image(s), initrd(s), etc to the disk, and <!--
 +
--> create/edit <tt>syslinux.cfg</tt> and help files if desired:
  
:::<tt>copy vmlinux a:</tt>
+
:::::<span style="white-space:nowrap;"><code>copy vmlinux a:</code></span>
:::<tt>copy initrd.gz a:</tt>
+
:::::<span style="white-space:nowrap;"><code>copy initrd.gz a:</code></span>
  
 +
<!-- v.3.72 --><!--
 +
--><!-- == COMBOOT EXECUTABLES == --><!--
 +
--><!--  --><!--
 +
--><!-- Syslinux supports simple standalone programs, using a file format  --><!--
 +
--><!-- similar to DOS "<tt>.com</tt>" files.  A 32-bit version, called COM32, is also  --><!--
 +
--><!-- provided.  A simple API provides access to a limited set of filesystem  --><!--
 +
--><!-- and console functions. --><!--
 +
--><!--  --><!--
 +
--><!-- See the file [[doc/comboot|comboot.txt]] for more information on COMBOOT and COM32  --><!--
 +
--><!-- programs. --><!--
 +
--><!--  --><!--
 +
--><!--        -->
  
=COMBOOT EXECUTABLES=
+
== NOVICE PROTECTION ==
  
SYSLINUX supports simple standalone programs, using a file format similar to DOS "<tt>.com</tt>" filesA 32-bit version, called COM32, is also providedA simple API provides access to a limited set of filesystem and console functions.
+
Syslinux will attempt to detect booting on a machine with too little
 +
memory, which means the Linux boot sequence cannot completeIf so, a
 +
message is displayed and the boot sequence abortedHolding down the
 +
Ctrl key while booting disables this feature.
  
See the file [[doc/comboot|comboot.txt]] for more information on COMBOOT and COM32 programs.
+
Any file that SYSLINUX uses can be marked hidden, system or readonly
 +
if so is convenient; SYSLINUX ignores all file attributes. The
 +
SYSLINUX installer automatically sets the readonly/hidden/system
 +
attributes on <tt>LDLINUX.SYS</tt>.
  
  
=NOVICE PROTECTION=
+
== NOTES ON BOOTABLE CD-ROMS ==
  
SYSLINUX will attempt to detect booting on a machine with too little memory, which means the Linux boot sequence cannot complete.  If so, a message is displayed and the boot sequence aborted.  Holding down the Ctrl key while booting disables this feature.
+
SYSLINUX can be used to create bootdisk images for El&nbsp;
 
+
Torito-compatible bootable CD-ROMs.  However, it appears that many  
Any file that SYSLINUX uses can be marked hidden, system or readonly if so is convenient; SYSLINUX ignores all file attributes.  The SYSLINUX installer automatically sets the readonly/hidden/system attributes on <tt>LDLINUX.SYS</tt>.
+
BIOSes are very buggy when it comes to booting CD-ROMs.  Some users  
 
+
have reported that the following steps are helpful in making a CD-ROM  
 
+
that is bootable on the largest possible number of machines:
=NOTES ON BOOTABLE CD-ROMS=
+
 
+
SYSLINUX can be used to create bootdisk images for El Torito-compatible bootable CD-ROMs.  However, it appears that many BIOSes are very buggy when it comes to booting CD-ROMs.  Some users have reported that the following steps are helpful in making a CD-ROM that is bootable on the largest possible number of machines:
+
  
 
::a) Use the <tt>-s</tt> (safe, slow and stupid) option to SYSLINUX;
 
::a) Use the <tt>-s</tt> (safe, slow and stupid) option to SYSLINUX;
::b) Put the boot image as close to the beginning of the ISO 9660 filesystem as possible.
+
::b) Put the boot image as close to the beginning of the <!--
 +
--> ISO 9660 filesystem as possible.
  
A CD-ROM is so much faster than a floppy that the <tt>-s</tt> option shouldn't matter from a speed perspective.
+
A CD-ROM is so much faster than a floppy that the <tt>-s</tt> option shouldn't  
 +
matter from a speed perspective.
  
 
Of course, you probably want to use ISOLINUX instead.  See [[doc/isolinux|isolinux.txt]].
 
Of course, you probably want to use ISOLINUX instead.  See [[doc/isolinux|isolinux.txt]].
  
  
=BOOTING FROM A FAT FILESYSTEM PARTITION ON A HARD DISK=
+
== BOOTING FROM A FAT FILESYSTEM PARTITION ON A HARD DISK ==
  
SYSLINUX can boot from a FAT filesystem partition on a hard disk (including FAT32).  The installation procedure is identical to the procedure for installing it on a floppy, and should work under either DOS or Linux.  To boot from a partition, SYSLINUX needs to be launched from a Master Boot Record or another boot loader, just like DOS itself would.
+
SYSLINUX can boot from a FAT filesystem partition on a hard disk  
 +
(including FAT32).  The installation procedure is identical to the  
 +
procedure for installing it on a floppy, and should work under either  
 +
DOS or Linux.  To boot from a partition, SYSLINUX needs to be launched  
 +
from a Master Boot Record or another boot loader, just like DOS itself  
 +
would.
  
Under DOS, you can install a standard simple MBR on the primary hard disk by running the command:
+
Under DOS, you can install a standard simple MBR on the primary hard  
 +
disk by running the command:
  
::<tt>FDISK /MBR</tt>
+
:::::<span style="white-space:nowrap;"><code>FDISK /MBR</code></span>
  
 
Then use the FDISK command to mark the appropriate partition active.
 
Then use the FDISK command to mark the appropriate partition active.
  
A simple MBR, roughly on par with the one installed by DOS (but unencumbered), is included in the SYSLINUX distribution.  To install it under Linux, simply type:
+
A simple MBR, roughly on par with the one installed by DOS (but  
 +
unencumbered), is included in the Syslinux distribution.  To install  
 +
it under Linux, simply type:
  
::<tt>cat mbr.bin > /dev/XXX</tt>
+
<!-- The following command is not always recommended; see [[Mbr#Write]] -->
 +
:::<tt>cat mbr.bin > /dev/XXX</tt>
  
 
... where <tt>/dev/XXX</tt> is the device you wish to install it on.
 
... where <tt>/dev/XXX</tt> is the device you wish to install it on.
  
Under DOS or Win32, you can install the SYSLINUX MBR with the <tt>-m</tt> option to the SYSLINUX installer, and use the <tt>-a</tt> option to mark the current partition active:
+
Under DOS or Win32, you can install the SYSLINUX MBR with the <tt>-m</tt>  
 +
option to the SYSLINUX installer, and use the <tt>-a</tt> option to mark the  
 +
current partition active:
  
::<tt>syslinux -ma c:</tt>
+
:::::<span style="white-space:nowrap;"><code>syslinux -mai c:</code></span>
  
 
Note that this will also install SYSLINUX on the specified partition.
 
Note that this will also install SYSLINUX on the specified partition.
  
  
=HARDWARE INFORMATION=
+
== HARDWARE INFORMATION ==
  
I have started to maintain a web page of hardware with known problems.  There are, unfortunately, lots of broken hardware out there; especially early PXE stacks (for PXELINUX) have lots of problems.
+
I have started to maintain a web page of hardware with known  
 +
problems.  There are, unfortunately, lots of broken hardware out  
 +
there; especially early PXE stacks (for PXELINUX) have lots of  
 +
problems.
  
 
A list of problems, and workarounds (if known), is maintained at:
 
A list of problems, and workarounds (if known), is maintained at:
  
::http://syslinux.zytor.com/hardware.php
+
::[[Hardware_Compatibility|http://syslinux.zytor.com/hardware.php]]
  
  
=BOOT LOADER IDS USED=
+
== BOOT LOADER IDS USED ==
  
The Linux boot protocol supports a "boot loader ID", a single byte where the upper nybble specifies a boot loader family (3 = SYSLINUX) and the lower nybble is version or, in the case of SYSLINUX, media:
+
The Linux boot protocol supports a "boot loader ID", a single byte  
 +
where the upper nybble specifies a boot loader family (3 = Syslinux)  
 +
and the lower nybble is version or, in the case of Syslinux, media:
  
 
::0x31 (49) = SYSLINUX
 
::0x31 (49) = SYSLINUX
Line 535: Line 1,004:
 
::0x34 (52) = EXTLINUX
 
::0x34 (52) = EXTLINUX
  
In recent versions of Linux, this ID is available as <tt>/proc/sys/kernel/bootloader_type</tt>.
+
In recent versions of Linux, this ID is available as  
 +
<tt>/proc/sys/kernel/bootloader_type</tt>.
 +
 
 +
 
 +
== PATH RULES ==
 +
 
 +
The current working directory is *always* searched first, before <tt>PATH</tt>,
 +
when attempting to open a filename. The current working directory is
 +
not affected when specifying a file with an absolute path. For
 +
example, given the following file system layout,
 +
{|
 +
|
 +
/boot/
 +
/bin/
 +
ls.c32
 +
libls.c32
 +
/foo/
 +
libls.c32
 +
|}
 +
assuming that the current working directory is ''/boot/foo'', and assuming
 +
that ''libls.c32'' is a dependency of ''ls.c32'', executing ''/boot/bin/ls.c32''
 +
will cause ''/boot/foo/libls.c32'' to be loaded, not ''/boot/bin/libls.c32'',
 +
even if ''/boot/bin'' is specified in the <tt>PATH</tt> directive of a config file.
 +
 
 +
The reason that things work this way is that typically a user will
 +
install all library files in the Syslinux installation directory, as
 +
specified with the <tt>--directory</tt> installer option. This method allows
 +
the user to omit the <tt>PATH</tt> directive from their config file and still
 +
have things work correctly.
  
  
=BUG REPORTS=
+
== BUG REPORTS ==
  
I would appreciate hearing of any problems you have with SYSLINUX.  I would also like to hear from you if you have successfully used SYSLINUX, <u>''especially''</u> if you are using it for a distribution.
+
I would appreciate hearing of any problems you have with Syslinux.  I  
 +
would also like to hear from you if you have successfully used Syslinux,  
 +
<u>''especially''</u> if you are using it for a distribution.
  
If you are reporting problems, please include all possible information about your system and your BIOS; the vast majority of all problems reported turn out to be BIOS or hardware bugs, and I need as much information as possible in order to diagnose the problems.
+
If you are reporting problems, please include all possible information  
 +
about your system and your BIOS; the vast majority of all problems  
 +
reported turn out to be BIOS or hardware bugs, and I need as much  
 +
information as possible in order to diagnose the problems.
  
There is a mailing list for discussion among SYSLINUX users and for announcements of new and test versions.  To join, or to browse the archive, go to:
+
There is a mailing list for discussion among Syslinux users and for  
 +
announcements of new and test versions.  To join, or to browse the  
 +
archive, go to:
  
 
::http://www.zytor.com/mailman/listinfo/syslinux
 
::http://www.zytor.com/mailman/listinfo/syslinux
  
Please '''DO NOT''' send HTML messages or attachments to the mailing list (including multipart/alternative or similar.)  All such messages will be bounced.
+
Please '''DO NOT''' send HTML messages or attachments to the mailing list  
 +
(including multipart/alternative or similar). All such messages will  
 +
be bounced.

Revision as of 17:33, 21 December 2018

This document is partially outdated. Please see SYSLINUX and Config.
The content of doc/syslinux.txt (6.04-pre1, with minor corrections):

The Syslinux Project
A suite of bootloaders for Linux
Copyright 1994-2011 H. Peter Anvin and contributors

This program is provided under the terms of the GNU General Public License, version 2 or, at your option, any later version. There is no warranty, neither expressed nor implied, to the function of this program. Please see the included file COPYING for details.


Syslinux now has a home page at http://syslinux.zytor.com/

The Syslinux suite contains the following boot loaders ("derivatives"), for their respective boot media:

SYSLINUX - MS-DOS/Windows FAT filesystem
PXELINUX - PXE network booting
ISOLINUX - ISO9660 CD-ROM
EXTLINUX - Linux ext2/ext3 filesystem

For historical reasons, some of the sections in this document apply to the FAT loader (SYSLINUX) only; see pxelinux.txt, isolinux.txt and extlinux.txt for what differs in these versions. The all-caps term "SYSLINUX" generally refers to the FAT loader, whereas "Syslinux" refers to the project as a whole.

Help with cleaning up the docs would be greatly appreciated.


Options

These are the options common to all versions of Syslinux:

-s Safe, slow, stupid; uses simpler code that boots better
-f Force installing
-r Raid mode. If boot fails, tell the BIOS to boot the next device in the boot sequence (usually the next hard disk) instead of stopping with an error message. This is useful for RAID-1 booting.

These are only in the Windows version:

-m Mbr; install a bootable MBR sector to the beginning of the drive.
-a Active; marks the partition used active (=bootable)


CREATING A BOOTABLE LINUX FLOPPY

In order to create a bootable Linux floppy using SYSLINUX, prepare a normal MS-DOS formatted floppy. Copy one or more Linux kernel files to it, then execute the DOS command:

syslinux [-sfrmai][-d directory] a: [bootsecfile]

(or whichever drive letter is appropriate; the "[ ]" meaning optional).

Use "syslinux.com" (in the dos subdirectory of the distribution) for plain DOS (MS-DOS, DR-DOS, PC-DOS, FreeDOS...) or Win9x/ME.

Use "syslinux.exe" (in the win32 subdirectory of the distribution) for WinNT/2000/XP.

Under Linux, execute the command:

syslinux [-sfri][-d directory][-o offset] /dev/fd0

(or, again, whichever device is the correct one).

This will alter the boot sector on the disk and copy a file named LDLINUX.SYS into its root directory (or a subdirectory, if the -d option is specified).

The -s option, if given, will install a "safe, slow and stupid" version of SYSLINUX. This version may work on some very buggy BIOSes on which SYSLINUX would otherwise fail. If you find a machine on which the -s option is required to make it boot reliably, please send as much info about your machine as you can, and include the failure mode.

The -o option is used with a disk image file and specifies the byte offset of the filesystem image in the file.

For the DOS and Windows installers, the -m and -a options can be used on hard drives to write a Master Boot Record (MBR), and to mark the specific partition active.

On boot time, by default, the kernel will be loaded from the image named LINUX on the boot floppy. This default can be changed, see the section on the SYSLINUX config file.

If the Shift or Alt keys are held down during boot, or the Caps or Scroll locks are set, Syslinux will display a LILO-style "boot:" prompt. The user can then type a kernel file name followed by any kernel parameters. The Syslinux loader does not need to know about the kernel file in advance; all that is required is that it is a file located in the root directory on the disk.

There are two versions of the Linux installer; one in the "mtools" directory which requires no special privilege (other than write permission to the device where you are installing) but requires the mtools program suite to be available, and one in the "linux" directory which requires root privilege.


CONFIGURATION FILE

All options here apply to PXELINUX, ISOLINUX and EXTLINUX as well as SYSLINUX unless otherwise noted. See the respective .txt files.

All the configurable defaults in SYSLINUX can be changed by putting a file called "syslinux.cfg" in the root directory of the boot disk.

Starting with version 3.35, the configuration file can also be in either the /boot/syslinux or /syslinux directories (searched in that order). If that is the case, then all filenames are assumed to be relative to that same directory, unless preceded with a slash or backslash.

The configuration file is a text file in either UNIX or DOS format, containing one or more of the following items, each on its own line with optional leading whitespace. Case is insensitive for keywords; upper case is used here to indicate that a word should be typed verbatim.


# comment

A comment line. The whitespace after the hash mark is mandatory.

INCLUDE filename

Inserts the contents of another file at this point in the configuration file. Files can currently be nested up to 16 levels deep, but it is not guaranteed that more than 8 levels will be supported in the future.

DEFAULT kernel options...

Sets the default command line. If Syslinux boots automatically, it will act just as if the commands after DEFAULT had been typed in at the "boot:" prompt.
If no configuration file is present, or no DEFAULT entry is present in the config file, the default is "linux auto" an error message is displayed and the boot: prompt is shown.
NOTE: Earlier versions of SYSLINUX used to automatically append the string "auto" to whatever the user specified using the DEFAULT command. As of version 1.54, this is no longer true, as it caused problems when using a shell as a substitute for "init." You may want to include this option manually.

UI module options...

Selects a specific user interface module (typically menu.c32 or vesamenu.c32). The command-line interface treats this as a directive that overrides the DEFAULT and PROMPT directives.

APPEND options...

Add one or more options to the kernel command line. These are added both for automatic and manual boots. The options are added at the very beginning of the kernel command line, usually permitting explicitly entered kernel options to override them. This is the equivalent of the LILO "append" option.

SYSAPPEND bitmask
IPAPPEND bitmask

The SYSAPPEND option was introduced in Syslinux 5.10; it is an enhancement of a previous option IPAPPEND which was only available on PXELINUX. bitmask is interpreted as decimal format unless prefixed with "0x" for hexadecimal or "0" (zero) for octal.
1: indicates that an option of the following format should be generated and added to the kernel command line:
ip=<client-ip>:<boot-server-ip>:<gw-ip>:<netmask>
... based on the input from the DHCP/BOOTP or PXE boot server.
THE USE OF THIS OPTION IS NOT RECOMMENDED. If you have to use it, it is probably an indication that your network configuration is broken. Using just "ip=dhcp" on the kernel command line is a preferrable option, or, better yet, run dhcpcd/dhclient, from an initrd if necessary.
NOTE: The use of this option is no substitute for running a DHCP client in the booted system. Without regular renewals, the lease acquired by the PXE BIOS will expire, making the IP address available for reuse by the DHCP server.
This option is empty for non-PXELINUX.
2: indicates that an option of the following format should be generated and added to the kernel command line:
BOOTIF=<hardware-address-of-boot-interface>
... in dash-separated hexadecimal with leading hardware type (same as for the configuration file; see pxelinux.txt).
This allows an initrd program to determine from which interface the system booted.
This option is empty for non-PXELINUX.
4: indicates that an option of the following format should be generated and added to the kernel command line:
SYSUUID=<system uuid>
... in lower case hexadecimal in the format normally used for UUIDs (same as for the configuration file; see pxelinux.txt). This may not be available if no valid UUID is found on the system.
8: indicate the CPU family and certain particularly significant CPU feature bits:
CPU=<family><features>
The <family> is a single digit from 3 (i386) to 6 (i686 or higher). The following CPU features are currently reported; additional flags may be added in the future:
	P	Physical Address Extension (PAE)
	V	Intel Virtualization Technology (VT/VMX)
	T	Intel Trusted Exection Technology (TXT/SMX)
	X	Execution Disable (XD/NX)
	L	Long Mode (x86-64)
	S	AMD SMX virtualization
This was added in 5.10.
The following strings are derived from DMI/SMBIOS information if available; these are all new in version 5.10:
	Bit    	String		Significance
	-------------------------------------------------------------
	0x00010	SYSVENDOR=	System vendor name
	0x00020	SYSPRODUCT=	System product name
	0x00040	SYSVERSION=	System version
	0x00080	SYSSERIAL=	System serial number
	0x00100	SYSSKU=		System SKU
	0x00200	SYSFAMILY=	System family
	0x00400	MBVENDOR=	Motherboard vendor name
	0x00800	MBPRODUCT=	Motherboard product name
	0x01000	MBVERSION=	Motherboard version
	0x02000	MBSERIAL=	Motherboard serial number
	0x04000	MBASSET=	Motherboard asset tag
	0x08000	BIOSVENDOR=	BIOS vendor name
	0x10000	BIOSVERSION=	BIOS version
	0x20000	SYSFF=		System form factor
If these strings contain whitespace they are replaced with underscores (_).
The system form factor value is a number defined in the SMBIOS specification, available at http://www.dmtf.org/. As of version 2.7.1 of the specification, the following values are defined:
	  1	Other
	  2	Unknown
	  3	Desktop
	  4	Low Profile Desktop
	  5	Pizza Box
	  6	Mini Tower
	  7	Tower
	  8	Portable
	  9	Laptop
	 10	Notebook
	 11	Handheld
	 12	Docking Station
	 13	All-in-One     
	 14	SubNotebook    
	 15	Space-saving   
	 16	Lunch Box      
	 17	Main Server Chassis
	 18	Expansion Chassis
	 19	SubChassis
	 20	Bus Expansion Chassis
	 21	Peripheral Chassis
	 22	RAID Chassis
	 23	Rack Mount Chassis
	 24	Sealed-case PC
	 25	Multi-system chassis
	 26	Compact PCI
	 27	Advanced TCA
	 28	Blade
	 29	Blade Enclosure


0x40000: Append a file system UUID string. For EXT2/3/4, this is the typical file system UUID. For FAT12/16/32, this is the 32-bit file system serial number (ie DA1A-0B2E).
FSUUID=<FS-UUID>


SENDCOOKIES bitmask   [PXELINUX only]

When downloading files over http, the SYSAPPEND strings are prepended with "_Syslinux_" and sent to the server as cookies. The cookies are URL-encoded; whitespace is *not* replaced with underscores.
This command limits the cookies send; 0 means no cookies. The default is -1, meaning send all cookies.
This option is "sticky" and is not automatically reset when loading a new configuration file with the CONFIG command.

LABEL label

KERNEL image
APPEND options...
SYSAPPEND flag_val   [5.10+]
IPAPPEND flag_val   [5.10+ or PXELINUX only]
Indicates that if "label" is entered as the kernel to boot, Syslinux should instead boot "image", and the specified APPEND and SYSAPPEND options should be used instead of the ones specified in the global section of the file (before the first LABEL command). The default for "image" is the same as "label", and if no APPEND is given the default is to use the global entry (if any).
Starting with version 3.62, the number of LABEL statements is virtually unlimited.
Note that LILO uses the syntax:
       image = mykernel
         label = mylabel
         append = "myoptions"
... whereas Syslinux uses the syntax:
       label mylabel
         kernel mykernel
         append myoptions
Note: The "kernel" doesn't have to be a Linux kernel; it can be a boot sector or a COMBOOT file (see below).
Since version 3.32 label names are no longer mangled into DOS format (for SYSLINUX).
The following commands are available after a LABEL statement:
LINUX image - Linux kernel image (default)
BOOT image - Bootstrap program (.bs, .bin)
BSS image - BSS image (.bss)
PXE image - PXE Network Bootstrap Program (.0)
FDIMAGE image - Floppy disk image (.img)
COMBOOT image - COMBOOT program (.com, .cbt)
COM32 image - COM32 program (.c32)
CONFIG image - New configuration file
Using one of these keywords instead of KERNEL forces the filetype, regardless of the filename.
CONFIG means restart the boot loader using a different configuration file. The configuration file is read, the working directory is changed (if specified via an APPEND), then the configuration file is parsed.
APPEND -
Append nothing. APPEND with a single hyphen as argument in a LABEL section can be used to override a global APPEND.
LOCALBOOT type   [ISOLINUX, PXELINUX]
Attempt a different local boot method. The special value -1 causes the boot loader to report failure to the BIOS, which, on recent BIOSes, should mean that the next boot device in the boot sequence should be activated. Values other than those documented may produce undesired results.
On PXELINUX, "type" 0 means perform a normal boot. "type" 4 will perform a local boot with the Universal Network Driver Interface (UNDI) driver still resident in memory. Finally, "type" 5 will perform a local boot with the entire PXE stack, including the UNDI driver, still resident in memory. All other values are undefined. If you don't know what the UNDI or PXE stacks are, don't worry -- you don't want them, just specify 0.
On ISOLINUX, the "type" specifies the local drive number to boot from; 0x00 is the primary floppy drive and 0x80 is the primary hard drive.
INITRD initrd_file
Starting with version 3.71, an initrd can be specified in a separate statement (INITRD) instead of as part of the APPEND statement; this functionally appends "initrd=initrd_file" to the kernel command line.
It supports multiple filenames separated by commas. This is mostly useful for initramfs, which can be composed of multiple separate cpio or cpio.gz archives. Note: all files except the last one are zero-padded to a 4K page boundary. This should not affect initramfs.

IMPLICIT flag_val

If flag_val is 0, do not load a kernel image unless it has been explicitly named in a LABEL statement. The default is 1.

ALLOWOPTIONS flag_val

If flag_val is 0, the user is not allowed to specify any arguments on the kernel command line. The only options recognized are those specified in an APPEND statement. The default is 1.

TIMEOUT timeout

Indicates how long to wait at the boot: prompt until booting automatically, in units of 1/10 s. The timeout is cancelled as soon as the user types anything on the keyboard, the assumption being that the user will complete the command line already begun. A timeout of zero will disable the timeout completely, this is also the default.

TOTALTIMEOUT timeout

Indicates how long to wait until booting automatically, in units of 1/10 s. This timeout is not cancelled by user input, and can thus be used to deal with serial port glitches or "the user walked away" type situations. A timeout of zero will disable the timeout completely, this is also the default.
Both TIMEOUT and TOTALTIMEOUT can be used together, for example:
	# Wait 5 seconds unless the user types something, but
	# always boot after 15 minutes.
	TIMEOUT 50
	TOTALTIMEOUT 9000

ONTIMEOUT kernel options...

Sets the command line invoked on a timeout. Normally this is the same thing as invoked by "DEFAULT". If this is specified, then "DEFAULT" is used only if the user presses <Enter> to boot.

ONERROR kernel options...

If a kernel image is not found (either due to it not existing, or because IMPLICIT is set), run the specified command. The faulty command line is appended to the specified options, so if the ONERROR directive reads as:
ONERROR xyzzy plugh
... and the command line as entered by the user is:
foo bar baz
... Syslinux will execute the following as if entered by the user:
xyzzy plugh foo bar baz

SERIAL port [baudrate [flowcontrol]]

Enables a serial port to act as the console. "port" is a number (0 = /dev/ttyS0 = COM1, etc.) or an I/O port address (e.g. 0x3F8); if "baudrate" is omitted, the baud rate defaults to 9600 bps. The serial parameters are hardcoded to be 8 bits, no parity, 1 stop bit.
"flowcontrol" is a combination of the following bits:
   0x001 - Assert DTR
   0x002 - Assert RTS
   0x008 - Enable interrupts
   0x010 - Wait for CTS assertion
   0x020 - Wait for DSR assertion
   0x040 - Wait for RI assertion
   0x080 - Wait for DCD assertion
   0x100 - Ignore input unless CTS asserted
   0x200 - Ignore input unless DSR asserted
   0x400 - Ignore input unless RI asserted
   0x800 - Ignore input unless DCD asserted
All other bits are reserved.
Typical values are:
       0 - No flow control (default)
   0x303 - Null modem cable detect
   0x013 - RTS/CTS flow control
   0x813 - RTS/CTS flow control, modem input
   0x023 - DTR/DSR flow control
   0x083 - DTR/DCD flow control
For the SERIAL directive to be guaranteed to work properly, it should be the first directive in the configuration file.
NOTE: "port" values from 0 to 3 means the first four serial ports detected by the BIOS. They may or may not correspond to the legacy port values 0x3F8, 0x2F8, 0x3E8, 0x2E8.
Enabling interrupts (setting the 0x008 bit) may give better responsiveness without setting the NOHALT option, but could potentially cause problems with buggy BIOSes.
This option is "sticky" and is not automatically reset when loading a new configuration file with the CONFIG command.

NOHALT flag_val

If flag_val is 1, don't halt the processor while idle. Halting the processor while idle significantly reduces the power consumption, but can cause poor responsiveness to the serial console, especially when using scripts to drive the serial console, as opposed to human interaction.

CONSOLE flag_val

If flag_val is 0, disable output to the normal video console.
If flag_val is 1, enable output to the video console (this is the default).
Some BIOSes try to forward this to the serial console and sometimes make a total mess thereof, so this option lets you disable the video console on these systems.

FONT filename

Load a font in .psf format before displaying any output (except the copyright line, which is output as ldlinux.sys itself is loaded). Syslinux only loads the font onto the video card; if the .psf file contains a Unicode table it is ignored. This only works on EGA and VGA cards; hopefully it should do nothing on others.

KBDMAP keymap

Install a simple keyboard map. The keyboard remapper used is very simplistic (it simply remaps the keycodes received from the BIOS, which means that only the key combinations relevant in the default layout -- usually U.S. English -- can be mapped) but should at least help people with AZERTY keyboard layout and the locations of "=" and "," (two special characters used heavily on the Linux kernel command line).
The included program keytab-lilo.pl from the LILO distribution can be used to create such keymaps. The file keytab-lilo.txt contains the documentation for this program.

DISPLAY filename

Displays the indicated file on the screen at boot time (before the boot: prompt, if displayed). Please see the section below on DISPLAY files.
NOTE: If the file is missing, this option is simply ignored.

SAY message

Prints the message on the screen.

PROMPT flag_val

If flag_val is 0, display the boot: prompt only if the Shift or Alt key is pressed, or Caps Lock or Scroll Lock is set (this is the default). If flag_val is 1, always display the boot: prompt.

NOESCAPE flag_val

If flag_val is set to 1, ignore the Shift/Alt/Caps Lock/Scroll  Lock escapes. Use this (together with PROMPT 0) to force the default boot alternative.

NOCOMPLETE flag_val

If flag_val is set to 1, the Tab key does not display labels at the boot: prompt.

F1 filename
F2 filename

...etc...

F9 filename
F10 filename
F11 filename
F12 filename

Displays the indicated file on the screen when a function key is pressed at the boot: prompt. This can be used to implement pre-boot online help (presumably for the kernel command line options). Please see the section below on DISPLAY files.
When using the serial console, press <Ctrl-F><digit> to get to the help screens, e.g. <Ctrl-F><2> to get to the F2 screen.
For F10-F12, hit <Ctrl-F><A>, <Ctrl-F><B>, <Ctrl-F><C>. For compatibility with earlier versions, F10 can also be entered as <Ctrl-F><0>.

PATH path

Specify a colon-separated (':') list of directories to search when attempting to load modules. This directive is useful for specifying the directories containing the lib*.c32 library files as other modules may be dependent on these files, but may not reside in the same directory. The list of directories is searched in order. Please see the section below on PATH RULES.


Blank lines are ignored.

Note that the configuration file is not completely decoded. Syntax different from the one described above may still work correctly in this version of Syslinux, but may break in a future one.


DISPLAY FILE FORMAT

DISPLAY and function-key help files are text files in either DOS or UNIX format (with or without <CR>). In addition, the following special codes are interpreted:

< FF >
< FF > = <Ctrl-L> = ASCII 12

Clear the screen, home the cursor. Note that the screen is filled with the current display color.

< SI ><bg><fg>
< SI > = <Ctrl-O> = ASCII 15

Set the display colors to the specified background and foreground colors, where <bg> and <fg> are hex digits, corresponding to the standard PC display attributes:
	0 = black       	8 = dark grey
	1 = dark blue   	9 = bright blue
	2 = dark green  	a = bright green
	3 = dark cyan   	b = bright cyan
	4 = dark red    	c = bright red
	5 = dark purple 	d = bright purple
	6 = brown       	e = yellow
	7 = light grey  	f = white
Picking a bright color (8-f) for the background results in the corresponding dark color (0-7), with the foreground flashing.
Colors are not visible over the serial console.

< CAN >filename<newline>
< CAN > = <Ctrl-X> = ASCII 24

If a VGA display is present, enter graphics mode and display the graphic included in the specified file. The file format is an ad hoc format called LSS16; the included Perl program "ppmtolss16" can be used to produce these images. This Perl program also includes the file format specification.
The image is displayed in 640x480 16-color mode. Once in graphics mode, the display attributes (set by <SI> code sequences) work slightly differently: the background color is ignored, and the foreground colors are the 16 colors specified in the image file. For that reason, ppmtolss16 allows you to specify that certain colors should be assigned to specific color indices.
Color indices 0 and 7, in particular, should be chosen with care: 0 is the background color, and 7 is the color used for the text printed by Syslinux itself.

< EM >
< EM > = <Ctrl-Y> = ASCII 25

If we are currently in graphics mode, return to text mode.

< DLE > .. < ETB >
<Ctrl-P>..<Ctrl-W> = ASCII 16-23

These codes can be used to select which modes to print a certain part of the message file in. Each of these control characters select a specific set of modes (text screen, graphics screen, serial port) for which the output is actually displayed:
	Character			Text	Graph	Serial
	------------------------------------------------------
	<DLE> = <Ctrl-P> = ASCII 16	No	No	No
	<DC1> = <Ctrl-Q> = ASCII 17	Yes	No	No
	<DC2> = <Ctrl-R> = ASCII 18	No	Yes	No
	<DC3> = <Ctrl-S> = ASCII 19	Yes	Yes	No
	<DC4> = <Ctrl-T> = ASCII 20	No	No	Yes
	<NAK> = <Ctrl-U> = ASCII 21	Yes	No	Yes
	<SYN> = <Ctrl-V> = ASCII 22	No	Yes	Yes
	<ETB> = <Ctrl-W> = ASCII 23	Yes	Yes	Yes
For example:
	<DC1>Text mode<DC2>Graphics mode<DC4>Serial port<ETB>
... will actually print out which mode the console is in!

< SUB >
< SUB > = <Ctrl-Z> = ASCII 26

End of file (DOS convention).

< BEL >
< BEL > = <Ctrl-G> = ASCII 7

Beep the speaker.


COMMAND LINE KEYSTROKES

The command line prompt supports the following keystrokes:

<Enter>		boot specified command line
<BackSpace>	erase one character
<Ctrl-U>		erase the whole line
<Ctrl-V>		display the current Syslinux version
<Ctrl-W>		erase one word
<Ctrl-X>		force text mode
<Tab>		list matching labels
<F1>..<F12>	help screens (if configured)
<Ctrl-F><digit>	equivalent to F1..F10
<Ctrl-C>		interrupt boot in progress
<Esc>		interrupt boot in progress
<Ctrl-N>		display network information (PXELINUX only)

OTHER OPERATING SYSTEMS

This version of Syslinux supports chain loading of other operating systems (such as MS-DOS and its derivatives, including Windows 95/98).

Chain loading requires the boot sector of the foreign operating system to be stored in a file in the root directory of the filesystem. Because neither Linux kernels, nor boot sector images have reliable magic numbers, Syslinux will look at the file extension. The following extensions are recognized (case insensitive):

 none or other		Linux kernel image
 .0			PXE bootstrap program (NBP) [PXELINUX only]
 .bin			"CD boot sector" [ISOLINUX only]
 .bs			Boot sector [SYSLINUX only]
 .bss			Boot sector, DOS superblock will be patched in [SYSLINUX only]
 .c32			COM32 image (32-bit COMBOOT ELF)
 .cbt			COMBOOT image (not runnable from DOS) [-4.xx]
 .com			COMBOOT image (runnable from DOS) [-4.xx]
 .img			Disk image [ISOLINUX only]

For filenames given on the command line, Syslinux will search for the file by adding extensions in the order listed above if the plain filename is not found. Filenames in KERNEL statements must be fully qualified.

If this is specified with one of the keywords LINUX, BOOT, BSS, FDIMAGE, COMBOOT, COM32, or CONFIG instead of KERNEL, the filetype is considered to be the one specified regardless of the filename.


BOOTING DOS (OR OTHER SIMILAR OPERATING SYSTEMS)

This section applies to SYSLINUX only, not to PXELINUX or ISOLINUX. See isolinux.txt for an equivalent procedure for ISOLINUX.

This is the recommended procedure for creating a SYSLINUX disk that can boot either DOS or Linux. This example assumes the drive is A: in DOS and /dev/fd0 in Linux; for other drives, substitute the appropriate drive designator.

Linux procedure

1.

Make a DOS bootable disk. This can be done either by specifying the /s option when formatting the disk in DOS, or by running the DOS command SYS (this can be done under DOSEMU if DOSEMU has direct device access to the relevant drive):
format a: /s
or
sys a:

2.

Boot Linux. Copy the DOS boot sector from the disk into a file:
dd if=/dev/fd0 of=dos.bss bs=512 count=1

3.

Run SYSLINUX on the disk:
syslinux -i /dev/fd0

4.

Mount the disk and copy the DOS boot sector file to it. The file must have extension .bss:
mount -t msdos /dev/fd0 /mnt
cp dos.bss /mnt

5.

Copy the Linux kernel image(s), initrd(s), etc to the disk, and create/edit syslinux.cfg and help files if desired:
cp vmlinux /mnt
cp initrd.gz /mnt

6.

Unmount the disk (if applicable).
umount /mnt

DOS/Windows procedure

To make this installation in DOS only, you need the utility copybs.com (included with Syslinux) as well as the syslinux.com installer. If you are on a WinNT-based system (WinNT, Win2k, WinXP or later), use syslinux.exe instead.

1.

Make a DOS bootable disk. This can be done either by specifying the /s option when formatting the disk in DOS, or by running the DOS command SYS:
format a: /s
or
sys a:

2.

Copy the DOS boot sector from the disk into a file. The file must have extension .bss:
copybs a: a:dos.bss

3.

Run SYSLINUX on the disk:
syslinux -i a:

4.

Copy the Linux kernel image(s), initrd(s), etc to the disk, and create/edit syslinux.cfg and help files if desired:
copy vmlinux a:
copy initrd.gz a:


NOVICE PROTECTION

Syslinux will attempt to detect booting on a machine with too little memory, which means the Linux boot sequence cannot complete. If so, a message is displayed and the boot sequence aborted. Holding down the Ctrl key while booting disables this feature.

Any file that SYSLINUX uses can be marked hidden, system or readonly if so is convenient; SYSLINUX ignores all file attributes. The SYSLINUX installer automatically sets the readonly/hidden/system attributes on LDLINUX.SYS.


NOTES ON BOOTABLE CD-ROMS

SYSLINUX can be used to create bootdisk images for El  Torito-compatible bootable CD-ROMs. However, it appears that many BIOSes are very buggy when it comes to booting CD-ROMs. Some users have reported that the following steps are helpful in making a CD-ROM that is bootable on the largest possible number of machines:

a) Use the -s (safe, slow and stupid) option to SYSLINUX;
b) Put the boot image as close to the beginning of the ISO 9660 filesystem as possible.

A CD-ROM is so much faster than a floppy that the -s option shouldn't matter from a speed perspective.

Of course, you probably want to use ISOLINUX instead. See isolinux.txt.


BOOTING FROM A FAT FILESYSTEM PARTITION ON A HARD DISK

SYSLINUX can boot from a FAT filesystem partition on a hard disk (including FAT32). The installation procedure is identical to the procedure for installing it on a floppy, and should work under either DOS or Linux. To boot from a partition, SYSLINUX needs to be launched from a Master Boot Record or another boot loader, just like DOS itself would.

Under DOS, you can install a standard simple MBR on the primary hard disk by running the command:

FDISK /MBR

Then use the FDISK command to mark the appropriate partition active.

A simple MBR, roughly on par with the one installed by DOS (but unencumbered), is included in the Syslinux distribution. To install it under Linux, simply type:

cat mbr.bin > /dev/XXX

... where /dev/XXX is the device you wish to install it on.

Under DOS or Win32, you can install the SYSLINUX MBR with the -m option to the SYSLINUX installer, and use the -a option to mark the current partition active:

syslinux -mai c:

Note that this will also install SYSLINUX on the specified partition.


HARDWARE INFORMATION

I have started to maintain a web page of hardware with known problems. There are, unfortunately, lots of broken hardware out there; especially early PXE stacks (for PXELINUX) have lots of problems.

A list of problems, and workarounds (if known), is maintained at:

http://syslinux.zytor.com/hardware.php


BOOT LOADER IDS USED

The Linux boot protocol supports a "boot loader ID", a single byte where the upper nybble specifies a boot loader family (3 = Syslinux) and the lower nybble is version or, in the case of Syslinux, media:

0x31 (49) = SYSLINUX
0x32 (50) = PXELINUX
0x33 (51) = ISOLINUX
0x34 (52) = EXTLINUX

In recent versions of Linux, this ID is available as /proc/sys/kernel/bootloader_type.


PATH RULES

The current working directory is *always* searched first, before PATH, when attempting to open a filename. The current working directory is not affected when specifying a file with an absolute path. For example, given the following file system layout,

	 /boot/
		/bin/
			ls.c32
			libls.c32
		/foo/
			libls.c32

assuming that the current working directory is /boot/foo, and assuming that libls.c32 is a dependency of ls.c32, executing /boot/bin/ls.c32 will cause /boot/foo/libls.c32 to be loaded, not /boot/bin/libls.c32, even if /boot/bin is specified in the PATH directive of a config file.

The reason that things work this way is that typically a user will install all library files in the Syslinux installation directory, as specified with the --directory installer option. This method allows the user to omit the PATH directive from their config file and still have things work correctly.


BUG REPORTS

I would appreciate hearing of any problems you have with Syslinux. I would also like to hear from you if you have successfully used Syslinux, especially if you are using it for a distribution.

If you are reporting problems, please include all possible information about your system and your BIOS; the vast majority of all problems reported turn out to be BIOS or hardware bugs, and I need as much information as possible in order to diagnose the problems.

There is a mailing list for discussion among Syslinux users and for announcements of new and test versions. To join, or to browse the archive, go to:

http://www.zytor.com/mailman/listinfo/syslinux

Please DO NOT send HTML messages or attachments to the mailing list (including multipart/alternative or similar). All such messages will be bounced.