syslinux.doc

linux内核

			       SYSLINUX

		   A suite of bootloaders for Linux

		Copyright (C) 1994-2005 H. Peter Anvin

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.

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

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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 applies
to the FAT loader only; see pxelinux.doc, isolinux.doc and
extlinux.doc for what differs in these versions.

Help with cleaning up the docs would be greatly appreciated.


   ++++ 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 [-s] a:

(or whichever drive letter is appropriate; the [] meaning -s is 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 [-s] [-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.

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.

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 "unix" directory
which requires root privilege.


   ++++ CONFIGURATION FILE ++++

All the configurable defaults in SYSLINUX can be changed by putting a
file called SYSLINUX.CFG in the root directory of the boot floppy.  This
is a text file in either UNIX or DOS format, containing one or more of
the following items (case is insensitive for keywords; upper case is used
here to indicate that a word should be typed verbatim):

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

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

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.

        If no configuration file is present, or no DEFAULT entry is
        present in the config file, the default is "linux auto".

	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.

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.

IPAPPEND flag_val			[PXELINUX only]
	The IPAPPEND option is available only on PXELINUX.  The
	flag_val is an OR of the following options:

	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.

	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.doc.)

	This allows an initrd program to determine from which
	interface the system booted.

LABEL label
  KERNEL image
  APPEND options...
  IPAPPEND flag_val			[PXELINUX only]
	Indicates that if "label" is entered as the kernel to boot,
        SYSLINUX should instead boot "image", and the specified APPEND
	and IPAPPEND 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 2.20, LABEL statements are compressed
	internally, therefore the maximum number of LABEL statements
	depends on their complexity.  Typical is around 600.  SYSLINUX
	will print an error message if the internal memory for labels
	is overrun.

        Note that LILO uses the syntax:
        image = mykernel
          label = mylabel
          append = "myoptions"

        ... whereas SYSLINUX uses the syntax:
        label mylabel
          kernel mykernel
          append myoptions

	Notes:	Labels are mangled as if they were filenames, and must be
		unique after mangling.  For example, two labels
		"v2.1.30" and "v2.1.31" will not be distinguishable
		under SYSLINUX, since both mangle to the same DOS filename.
		This is also true for "foo bar" and "foo baz".

		The "kernel" doesn't have to be a Linux kernel; it can
		be a boot sector or a COMBOOT file (see below.)

  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]
	On PXELINUX, specifying "LOCALBOOT 0" instead of a "KERNEL"
	option means invoking this particular label will cause a local
	disk boot instead of booting a kernel.

	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 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.  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.

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
	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.

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.doc
	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