root/doc/syslinux.txt

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1                         The Syslinux Project
2
3                   A suite of bootloaders for Linux
4
5         Copyright 1994-2011 H. Peter Anvin and contributors
6
7This program is provided under the terms of the GNU General Public
8License, version 2 or, at your option, any later version.  There is no
9warranty, neither expressed nor implied, to the function of this
10program.  Please see the included file COPYING for details.
11
12----------------------------------------------------------------------
13
14      Syslinux now has a home page at http://syslinux.zytor.com/
15
16----------------------------------------------------------------------
17
18The Syslinux suite contains the following boot loaders
19("derivatives"), for their respective boot media:
20
21        SYSLINUX - MS-DOS/Windows FAT filesystem
22        PXELINUX - PXE network booting
23        ISOLINUX - ISO9660 CD-ROM
24        EXTLINUX - Linux ext2/ext3 filesystem
25
26For historical reasons, some of the sections in this document applies
27to the FAT loader (SYSLINUX) only; see pxelinux.txt, isolinux.txt and
28extlinux.txt for what differs in these versions.  The all-caps term
29"SYSLINUX" generally refers to the FAT loader, whereas "Syslinux"
30refers to the project as a whole.
31
32Help with cleaning up the docs would be greatly appreciated.
33
34
35   ++++ Options ++++
36
37These are the options common to all versions of Syslinux:
38
39        -s      Safe, slow, stupid; uses simpler code that boots better
40        -f      Force installing
41        -r      Raid mode.  If boot fails, tell the BIOS to boot the next
42                device in the boot sequence (usually the next hard disk)
43                instead of stopping with an error message.
44                This is useful for RAID-1 booting.
45
46These are only in the Windows version:
47
48        -m      Mbr; install a bootable MBR sector to the beginning of the
49                drive.
50        -a      Active; marks the partition used active (=bootable)
51
52
53   ++++ CREATING A BOOTABLE LINUX FLOPPY +++
54
55In order to create a bootable Linux floppy using SYSLINUX, prepare a
56normal MS-DOS formatted floppy.  Copy one or more Linux kernel files to
57it, then execute the DOS command:
58
59        syslinux [-sfrma][-d directory] a: [bootsecfile]
60
61(or whichever drive letter is appropriate; the [] meaning optional.)
62
63Use "syslinux.com" (in the dos subdirectory of the distribution) for
64plain DOS (MS-DOS, DR-DOS, PC-DOS, FreeDOS...) or Win9x/ME.
65
66Use "syslinux.exe" (in the win32 subdirectory of the distribution) for
67WinNT/2000/XP.
68
69Under Linux, execute the command:
70
71        syslinux [-sfr][-d directory][-o offset] /dev/fd0
72
73(or, again, whichever device is the correct one.)
74
75This will alter the boot sector on the disk and copy a file named
76LDLINUX.SYS into its root directory (or a subdirectory, if the -d
77option is specified.)
78
79The -s option, if given, will install a "safe, slow and stupid"
80version of SYSLINUX.  This version may work on some very buggy BIOSes
81on which SYSLINUX would otherwise fail.  If you find a machine on
82which the -s option is required to make it boot reliably, please send
83as much info about your machine as you can, and include the failure
84mode.
85
86The -o option is used with a disk image file and specifies the byte
87offset of the filesystem image in the file.
88
89For the DOS and Windows installers, the -m and -a options can be used
90on hard drives to write a Master Boot Record (MBR), and to mark the
91specific partition active.
92
93If the Shift or Alt keys are held down during boot, or the Caps or Scroll
94locks are set, Syslinux will display a LILO-style "boot:" prompt.  The
95user can then type a kernel file name followed by any kernel parameters.
96The Syslinux loader does not need to know about the kernel file in
97advance; all that is required is that it is a file located in the root
98directory on the disk.
99
100There are two versions of the Linux installer; one in the "mtools"
101directory which requires no special privilege (other than write
102permission to the device where you are installing) but requires the
103mtools program suite to be available, and one in the "unix" directory
104which requires root privilege.
105
106
107   ++++ CONFIGURATION FILE ++++
108
109All options here apply to PXELINUX, ISOLINUX and EXTLINUX as well as
110SYSLINUX unless otherwise noted.  See the respective .txt files.
111
112All the configurable defaults in SYSLINUX can be changed by putting a
113file called "syslinux.cfg" in the root directory of the boot disk.
114
115Starting with version 3.35, the configuration file can also be in
116either the /boot/syslinux or /syslinux directories (searched in that
117order.)  If that is the case, then all filenames are assumed to be
118relative to that same directory, unless preceded with a slash or
119backslash.
120
121The configuration file is a text file in either UNIX or DOS format,
122containing one or more of the following items, each on its own line with
123optional leading whitespace.  Case is insensitive for keywords; upper
124case is used here to indicate that a word should be typed verbatim.
125
126#comment
127        A comment line.
128
129INCLUDE filename
130        Inserts the contents of another file at this point in the
131        configuration file. Files can currently be nested up to 16
132        levels deep, but it is not guaranteed that more than 8 levels
133        will be supported in the future.
134
135DEFAULT kernel options...
136        Sets the default command line.  If Syslinux boots automatically,
137        it will act just as if the entries after DEFAULT had been typed
138        in at the "boot:" prompt.
139
140        If no configuration file is present, or no DEFAULT entry is
141        present in the config file, an error message is displayed and
142        the boot: prompt is shown.
143
144UI module options...
145        Selects a specific user interface module (typically menu.c32
146        or vesamenu.c32).  The command-line interface treats this as a
147        directive that overrides the DEFAULT and PROMPT directives.
148
149APPEND options...
150        Add one or more options to the kernel command line.  These are
151        added both for automatic and manual boots.  The options are
152        added at the very beginning of the kernel command line,
153        usually permitting explicitly entered kernel options to override
154        them.  This is the equivalent of the LILO "append" option.
155
156IPAPPEND flag_val                       [PXELINUX only]
157        The IPAPPEND option is available only on PXELINUX.  The
158        flag_val is an OR of the following options:
159
160        1: indicates that an option of the following format
161        should be generated and added to the kernel command line:
162
163                ip=<client-ip>:<boot-server-ip>:<gw-ip>:<netmask>
164
165        ... based on the input from the DHCP/BOOTP or PXE boot server.
166
167        NOTE: The use of this option is no substitute for running a
168        DHCP client in the booted system.  Without regular renewals,
169        the lease acquired by the PXE BIOS will expire, making the
170        IP address available for reuse by the DHCP server.
171
172        2: indicates that an option of the following format
173        should be generated and added to the kernel command line:
174
175                BOOTIF=<hardware-address-of-boot-interface>
176
177        ... in dash-separated hexadecimal with leading hardware type
178        (same as for the configuration file; see pxelinux.txt.)
179
180        This allows an initrd program to determine from which
181        interface the system booted.
182
183        4: indicates that an option of the following format
184        should be generated and added to the kernel command line:
185
186                SYSUUID=<system uuid>
187
188        ... in lower case hexadecimal in the format normally used for
189        UUIDs (same as for the configuration file; see pxelinux.txt.)
190
191LABEL label
192    KERNEL image
193    APPEND options...
194    IPAPPEND flag_val                   [PXELINUX only]
195        Indicates that if "label" is entered as the kernel to boot,
196        Syslinux should instead boot "image", and the specified APPEND
197        and IPAPPEND options should be used instead of the ones
198        specified in the global section of the file (before the first
199        LABEL command.)  The default for "image" is the same as
200        "label", and if no APPEND is given the default is to use the
201        global entry (if any).
202
203        Starting with version 3.62, the number of LABEL statements is
204        virtually unlimited.
205
206        Note that LILO uses the syntax:
207        image = mykernel
208          label = mylabel
209          append = "myoptions"
210
211        ... whereas Syslinux uses the syntax:
212        label mylabel
213          kernel mykernel
214          append myoptions
215
216        Note: The "kernel" doesn't have to be a Linux kernel; it can
217              be a boot sector or a COMBOOT file (see below.)
218
219        Since version 3.32 label names are no longer mangled into DOS
220        format (for SYSLINUX.)
221
222    The following commands are available after a LABEL statement:
223
224    LINUX image                 - Linux kernel image (default)
225    BOOT image                  - Bootstrap program (.bs, .bin)
226    BSS image                   - BSS image (.bss)
227    PXE image                   - PXE Network Bootstrap Program (.0)
228    FDIMAGE image               - Floppy disk image (.img)
229    COMBOOT image               - COMBOOT program (.com, .cbt)
230    COM32 image                 - COM32 program (.c32)
231    CONFIG image                - New configuration file
232        Using one of these keywords instead of KERNEL forces the
233        filetype, regardless of the filename.
234
235        CONFIG means restart the boot loader using a different
236        configuration file.  The configuration file is read, the
237        working directory is changed (if specified via an APPEND), then
238        the configuration file is parsed.
239
240    APPEND -
241        Append nothing.  APPEND with a single hyphen as argument in a
242        LABEL section can be used to override a global APPEND.
243
244    LOCALBOOT type
245        Attempt a different local boot method.  The special value -1
246        causes the boot loader to report failure to the BIOS, which, on
247        recent BIOSes, should mean that the next boot device in the
248        boot sequence should be activated.  Values other than those
249        documented may produce undesired results.
250
251        On PXELINUX, "type" 0 means perform a normal boot.  "type" 4
252        will perform a local boot with the Universal Network Driver
253        Interface (UNDI) driver still resident in memory.  Finally,
254        "type" 5 will perform a local boot with the entire PXE
255        stack, including the UNDI driver, still resident in memory.
256        All other values are undefined.  If you don't know what the
257        UNDI or PXE stacks are, don't worry -- you don't want them,
258        just specify 0.
259
260        On ISOLINUX, the "type" specifies the local drive number to
261        boot from; 0x00 is the primary floppy drive and 0x80 is the
262        primary hard drive.
263
264    INITRD initrd_file
265        Starting with version 3.71, an initrd can be specified in a
266        separate statement (INITRD) instead of as part of the APPEND
267        statement; this functionally appends "initrd=initrd_file" to
268        the kernel command line.
269
270        It supports multiple filenames separated by commas.
271        This is mostly useful for initramfs, which can be composed of
272        multiple separate cpio or cpio.gz archives.
273        Note: all files except the last one are zero-padded to a
274        4K page boundary.  This should not affect initramfs.
275
276IMPLICIT flag_val
277        If flag_val is 0, do not load a kernel image unless it has been
278        explicitly named in a LABEL statement.  The default is 1.
279
280ALLOWOPTIONS flag_val
281        If flag_val is 0, the user is not allowed to specify any
282        arguments on the kernel command line.  The only options
283        recognized are those specified in an APPEND statement.  The
284        default is 1.
285
286TIMEOUT timeout
287        Indicates how long to wait at the boot: prompt until booting
288        automatically, in units of 1/10 s.  The timeout is cancelled as
289        soon as the user types anything on the keyboard, the assumption
290        being that the user will complete the command line already
291        begun.  A timeout of zero will disable the timeout completely,
292        this is also the default.
293
294TOTALTIMEOUT timeout
295        Indicates how long to wait until booting automatically, in
296        units of 1/10 s.  This timeout is *not* cancelled by user
297        input, and can thus be used to deal with serial port glitches
298        or "the user walked away" type situations.  A timeout of zero
299        will disable the timeout completely, this is also the default.
300
301        Both TIMEOUT and TOTALTIMEOUT can be used together, for
302        example:
303
304                # Wait 5 seconds unless the user types something, but
305                # always boot after 15 minutes.
306                TIMEOUT 50
307                TOTALTIMEOUT 9000
308
309ONTIMEOUT kernel options...
310        Sets the command line invoked on a timeout.  Normally this is
311        the same thing as invoked by "DEFAULT".  If this is specified,
312        then "DEFAULT" is used only if the user presses <Enter> to
313        boot.
314
315ONERROR kernel options...
316        If a kernel image is not found (either due to it not existing,
317        or because IMPLICIT is set), run the specified command.  The
318        faulty command line is appended to the specified options, so
319        if the ONERROR directive reads as:
320
321                ONERROR xyzzy plugh
322
323        ... and the command line as entered by the user is:
324
325                foo bar baz
326
327        ... Syslinux will execute the following as if entered by the
328        user:
329
330                xyzzy plugh foo bar baz
331
332SERIAL port [[baudrate] flowcontrol]
333        Enables a serial port to act as the console.  "port" is a
334        number (0 = /dev/ttyS0 = COM1, etc.) or an I/O port address
335        (e.g. 0x3F8); if "baudrate" is omitted, the baud rate defaults
336        to 9600 bps.  The serial parameters are hardcoded to be 8
337        bits, no parity, 1 stop bit.
338
339        "flowcontrol" is a combination of the following bits:
340        0x001 - Assert DTR
341        0x002 - Assert RTS
342        0x008 - Enable interrupts
343        0x010 - Wait for CTS assertion
344        0x020 - Wait for DSR assertion
345        0x040 - Wait for RI assertion
346        0x080 - Wait for DCD assertion
347        0x100 - Ignore input unless CTS asserted
348        0x200 - Ignore input unless DSR asserted
349        0x400 - Ignore input unless RI asserted
350        0x800 - Ignore input unless DCD asserted
351
352        All other bits are reserved.
353
354        Typical values are:
355
356            0 - No flow control (default)
357        0x303 - Null modem cable detect
358        0x013 - RTS/CTS flow control
359        0x813 - RTS/CTS flow control, modem input
360        0x023 - DTR/DSR flow control
361        0x083 - DTR/DCD flow control
362
363        For the SERIAL directive to be guaranteed to work properly, it
364        should be the first directive in the configuration file.
365
366        NOTE: "port" values from 0 to 3 means the first four serial
367        ports detected by the BIOS.  They may or may not correspond to
368        the legacy port values 0x3F8, 0x2F8, 0x3E8, 0x2E8.
369
370        Enabling interrupts (setting the 0x008 bit) may give better
371        responsiveness without setting the NOHALT option, but could
372        potentially cause problems with buggy BIOSes.
373
374NOHALT flag_val
375        If flag_val is 1, don't halt the processor while idle.
376        Halting the processor while idle significantly reduces the
377        power consumption, but can cause poor responsiveness to the
378        serial console, especially when using scripts to drive the
379        serial console, as opposed to human interaction.
380
381CONSOLE flag_val
382        If flag_val is 0, disable output to the normal video console.
383        If flag_val is 1, enable output to the video console (this is
384        the default.)
385
386        Some BIOSes try to forward this to the serial console and
387        sometimes make a total mess thereof, so this option lets you
388        disable the video console on these systems.
389
390FONT filename
391        Load a font in .psf format before displaying any output
392        (except the copyright line, which is output as ldlinux.sys
393        itself is loaded.)  Syslinux only loads the font onto the
394        video card; if the .psf file contains a Unicode table it is
395        ignored.  This only works on EGA and VGA cards; hopefully it
396        should do nothing on others.
397
398KBDMAP keymap
399        Install a simple keyboard map.  The keyboard remapper used is
400        *very* simplistic (it simply remaps the keycodes received from
401        the BIOS, which means that only the key combinations relevant
402        in the default layout -- usually U.S. English -- can be
403        mapped) but should at least help people with AZERTY keyboard
404        layout and the locations of = and , (two special characters
405        used heavily on the Linux kernel command line.)
406
407        The included program keytab-lilo.pl from the LILO distribution
408        can be used to create such keymaps.  The file keytab-lilo.txt
409        contains the documentation for this program.
410
411DISPLAY filename
412        Displays the indicated file on the screen at boot time (before
413        the boot: prompt, if displayed).  Please see the section below
414        on DISPLAY files.
415
416        NOTE: If the file is missing, this option is simply ignored.
417
418SAY message
419        Prints the message on the screen.
420
421PROMPT flag_val
422        If flag_val is 0, display the boot: prompt only if the Shift or Alt
423        key is pressed, or Caps Lock or Scroll lock is set (this is the
424        default).  If flag_val is 1, always display the boot: prompt.
425
426NOESCAPE flag_val
427        If flag_val is set to 1, ignore the Shift/Alt/Caps Lock/Scroll
428        Lock escapes.  Use this (together with PROMPT 0) to force the
429        default boot alternative.
430
431NOCOMPLETE flag_val
432        If flag_val is set to 1, the Tab key does not display labels
433        at the boot: prompt.
434
435F1 filename
436F2 filename
437   ...etc...
438F9 filename
439F10 filename
440F11 filename
441F12 filename
442        Displays the indicated file on the screen when a function key is
443        pressed at the boot: prompt.  This can be used to implement
444        pre-boot online help (presumably for the kernel command line
445        options.)  Please see the section below on DISPLAY files.
446
447        When using the serial console, press <Ctrl-F><digit> to get to
448        the help screens, e.g. <Ctrl-F><2> to get to the F2 screen.
449        For F10-F12, hit <Ctrl-F><A>, <Ctrl-F>B, <Ctrl-F>C.  For
450        compatibility with earlier versions, F10 can also be entered as
451        <Ctrl-F>0.
452
453Blank lines are ignored.
454
455Note that the configuration file is not completely decoded.  Syntax
456different from the one described above may still work correctly in this
457version of Syslinux, but may break in a future one.
458
459
460   ++++ DISPLAY FILE FORMAT ++++
461
462DISPLAY and function-key help files are text files in either DOS or UNIX
463format (with or without <CR>).  In addition, the following special codes
464are interpreted:
465
466<FF>                                    <FF> = <Ctrl-L> = ASCII 12
467        Clear the screen, home the cursor.  Note that the screen is
468        filled with the current display color.
469
470<SI><bg><fg>                            <SI> = <Ctrl-O> = ASCII 15
471        Set the display colors to the specified background and
472        foreground colors, where <bg> and <fg> are hex digits,
473        corresponding to the standard PC display attributes:
474
475        0 = black               8 = dark grey
476        1 = dark blue           9 = bright blue
477        2 = dark green          a = bright green
478        3 = dark cyan           b = bright cyan
479        4 = dark red            c = bright red
480        5 = dark purple         d = bright purple
481        6 = brown               e = yellow
482        7 = light grey          f = white
483
484        Picking a bright color (8-f) for the background results in the
485        corresponding dark color (0-7), with the foreground flashing.
486
487        Colors are not visible over the serial console.
488
489<CAN>filename<newline>                  <CAN> = <Ctrl-X> = ASCII 24
490        If a VGA display is present, enter graphics mode and display
491        the graphic included in the specified file.  The file format
492        is an ad hoc format called LSS16; the included Perl program
493        "ppmtolss16" can be used to produce these images.  This Perl
494        program also includes the file format specification.
495
496        The image is displayed in 640x480 16-color mode.  Once in
497        graphics mode, the display attributes (set by <SI> code
498        sequences) work slightly differently: the background color is
499        ignored, and the foreground colors are the 16 colors specified
500        in the image file.  For that reason, ppmtolss16 allows you to
501        specify that certain colors should be assigned to specific
502        color indicies.
503
504        Color indicies 0 and 7, in particular, should be chosen with
505        care: 0 is the background color, and 7 is the color used for
506        the text printed by Syslinux itself.
507
508<EM>                                    <EM> = <Ctrl-Y> = ASCII 25
509        If we are currently in graphics mode, return to text mode.
510
511<DLE>..<ETB>                            <Ctrl-P>..<Ctrl-W> = ASCII 16-23
512        These codes can be used to select which modes to print a
513        certain part of the message file in.  Each of these control
514        characters select a specific set of modes (text screen,
515        graphics screen, serial port) for which the output is actually
516        displayed:
517
518        Character                       Text    Graph   Serial
519        ------------------------------------------------------
520        <DLE> = <Ctrl-P> = ASCII 16     No      No      No
521        <DC1> = <Ctrl-Q> = ASCII 17     Yes     No      No
522        <DC2> = <Ctrl-R> = ASCII 18     No      Yes     No
523        <DC3> = <Ctrl-S> = ASCII 19     Yes     Yes     No
524        <DC4> = <Ctrl-T> = ASCII 20     No      No      Yes
525        <NAK> = <Ctrl-U> = ASCII 21     Yes     No      Yes
526        <SYN> = <Ctrl-V> = ASCII 22     No      Yes     Yes
527        <ETB> = <Ctrl-W> = ASCII 23     Yes     Yes     Yes
528
529        For example:
530
531        <DC1>Text mode<DC2>Graphics mode<DC4>Serial port<ETB>
532
533        ... will actually print out which mode the console is in!
534
535<SUB>                                   <SUB> = <Ctrl-Z> = ASCII 26
536        End of file (DOS convention).
537
538<BEL>                                   <BEL> = <Ctrl-G> = ASCII 7
539        Beep the speaker.
540
541
542   ++++ COMMAND LINE KEYSTROKES ++++
543
544The command line prompt supports the following keystrokes:
545
546<Enter>         boot specified command line
547<BackSpace>     erase one character
548<Ctrl-U>        erase the whole line
549<Ctrl-V>        display the current Syslinux version
550<Ctrl-W>        erase one word
551<Ctrl-X>        force text mode
552<Tab>           list matching labels
553<F1>..<F12>     help screens (if configured)
554<Ctrl-F><digit> equivalent to F1..F10
555<Ctrl-C>        interrupt boot in progress
556<Esc>           interrupt boot in progress
557<Ctrl-N>        display network information (PXELINUX only)
558
559
560   ++++ COMBOOT IMAGES AND OTHER OPERATING SYSTEMS ++++
561
562This version of Syslinux supports chain loading of other operating
563systems (such as MS-DOS and its derivatives, including Windows 95/98),
564as well as COMBOOT-style standalone executables (a subset of DOS .COM
565files; see separate section below.)
566
567Chain loading requires the boot sector of the foreign operating system
568to be stored in a file in the root directory of the filesystem.
569Because neither Linux kernels, boot sector images, nor COMBOOT files
570have reliable magic numbers, Syslinux will look at the file extension.
571The following extensions are recognized (case insensitive):
572
573  none or other Linux kernel image
574  .0            PXE bootstrap program (NBP) [PXELINUX only]
575  .bin          "CD boot sector" [ISOLINUX only]
576  .bs           Boot sector [SYSLINUX only]
577  .bss          Boot sector, DOS superblock will be patched in [SYSLINUX only]
578  .c32          COM32 image (32-bit COMBOOT)
579  .cbt          COMBOOT image (not runnable from DOS)
580  .com          COMBOOT image (runnable from DOS)
581  .img          Disk image [ISOLINUX only]
582
583For filenames given on the command line, Syslinux will search for the
584file by adding extensions in the order listed above if the plain
585filename is not found.  Filenames in KERNEL statements must be fully
586qualified.
587
588If this is specified with one of the keywords LINUX, BOOT, BSS,
589FDIMAGE, COMBOOT, COM32, or CONFIG instead of KERNEL, the filetype is
590considered to be the one specified regardless of the filename.
591
592
593      ++++ BOOTING DOS (OR OTHER SIMILAR OPERATING SYSTEMS) ++++
594
595This section applies to SYSLINUX only, not to PXELINUX or ISOLINUX.
596See isolinux.txt for an equivalent procedure for ISOLINUX.
597
598This is the recommended procedure for creating a SYSLINUX disk that
599can boot either DOS or Linux.  This example assumes the drive is A: in
600DOS and /dev/fd0 in Linux; for other drives, substitute the
601appropriate drive designator.
602
603   ---- Linux procedure ----
604
6051. Make a DOS bootable disk.  This can be done either by specifying
606   the /s option when formatting the disk in DOS, or by running the
607   DOS command SYS (this can be done under DOSEMU if DOSEMU has
608   direct device access to the relevant drive):
609
610        format a: /s
611   or
612        sys a:
613
6142. Boot Linux.  Copy the DOS boot sector from the disk into a file:
615
616        dd if=/dev/fd0 of=dos.bss bs=512 count=1
617
6183. Run SYSLINUX on the disk:
619
620        syslinux /dev/fd0
621
6224. Mount the disk and copy the DOS boot sector file to it.  The file
623   *must* have extension .bss:
624
625        mount -t msdos /dev/fd0 /mnt
626        cp dos.bss /mnt
627
6285. Copy the Linux kernel image(s), initrd(s), etc to the disk, and
629   create/edit syslinux.cfg and help files if desired:
630
631        cp vmlinux /mnt
632        cp initrd.gz /mnt
633
6346. Unmount the disk (if applicable.)
635
636        umount /mnt
637
638   ---- DOS/Windows procedure ----
639
640To make this installation in DOS only, you need the utility copybs.com
641(included with Syslinux) as well as the syslinux.com installer.  If
642you are on an WinNT-based system (WinNT, Win2k, WinXP or later), use
643syslinux.exe instead.
644
6451. Make a DOS bootable disk.  This can be done either by specifying
646   the /s option when formatting the disk in DOS, or by running the
647   DOS command SYS:
648
649        format a: /s
650   or
651        sys a:
652
6532. Copy the DOS boot sector from the disk into a file.  The file
654   *must* have extension .bss:
655
656        copybs a: a:dos.bss
657
6583. Run SYSLINUX on the disk:
659
660        syslinux a:
661
6624. Copy the Linux kernel image(s), initrd(s), etc to the disk, and
663   create/edit syslinux.cfg and help files if desired:
664
665        copy vmlinux a:
666        copy initrd.gz a:
667
668
669   ++++ COMBOOT EXECUTABLES ++++
670
671Syslinux supports simple standalone programs, using a file format
672similar to DOS ".com" files.  A 32-bit version, called COM32, is also
673provided.  A simple API provides access to a limited set of filesystem
674and console functions.
675
676See the file comboot.txt for more information on COMBOOT and COM32
677programs.
678
679
680   ++++ NOVICE PROTECTION ++++
681
682Syslinux will attempt to detect booting on a machine with too little
683memory, which means the Linux boot sequence cannot complete.  If so, a
684message is displayed and the boot sequence aborted.  Holding down the
685Ctrl key while booting disables this feature.
686
687Any file that SYSLINUX uses can be marked hidden, system or readonly
688if so is convenient; SYSLINUX ignores all file attributes.  The
689SYSLINUX installed automatically sets the readonly/hidden/system
690attributes on LDLINUX.SYS.
691
692
693   ++++ NOTES ON BOOTABLE CD-ROMS ++++
694
695SYSLINUX can be used to create bootdisk images for El
696Torito-compatible bootable CD-ROMs.  However, it appears that many
697BIOSes are very buggy when it comes to booting CD-ROMs.  Some users
698have reported that the following steps are helpful in making a CD-ROM
699that is bootable on the largest possible number of machines:
700
701        a) Use the -s (safe, slow and stupid) option to SYSLINUX;
702        b) Put the boot image as close to the beginning of the
703           ISO 9660 filesystem as possible.
704
705A CD-ROM is so much faster than a floppy that the -s option shouldn't
706matter from a speed perspective.
707
708Of course, you probably want to use ISOLINUX instead.  See isolinux.txt.
709
710
711   ++++ BOOTING FROM A FAT FILESYSTEM PARTITION ON A HARD DISK ++++
712
713SYSLINUX can boot from a FAT filesystem partition on a hard disk
714(including FAT32).  The installation procedure is identical to the
715procedure for installing it on a floppy, and should work under either
716DOS or Linux.  To boot from a partition, SYSLINUX needs to be launched
717from a Master Boot Record or another boot loader, just like DOS itself
718would.
719
720Under DOS, you can install a standard simple MBR on the primary hard
721disk by running the command:
722
723        FDISK /MBR
724
725Then use the FDISK command to mark the appropriate partition active.
726
727A simple MBR, roughly on par with the one installed by DOS (but
728unencumbered), is included in the SYSLINUX distribution.  To install
729it under Linux, simply type:
730
731        cat mbr.bin > /dev/XXX
732
733... where /dev/XXX is the device you wish to install it on.
734
735Under DOS or Win32, you can install the SYSLINUX MBR with the -m
736option to the SYSLINUX installer, and use the -a option to mark the
737current partition active:
738
739        syslinux -ma c:
740
741Note that this will also install SYSLINUX on the specified partition.
742
743
744   ++++ HARDWARE INFORMATION +++
745
746I have started to maintain a web page of hardware with known
747problems.  There are, unfortunately, lots of broken hardware out
748there; especially early PXE stacks (for PXELINUX) have lots of
749problems.
750
751A list of problems, and workarounds (if known), is maintained at:
752
753        http://syslinux.zytor.com/hardware.php
754
755
756   ++++ BOOT LOADER IDS USED ++++
757
758The Linux boot protocol supports a "boot loader ID", a single byte
759where the upper nybble specifies a boot loader family (3 = Syslinux)
760and the lower nybble is version or, in the case of Syslinux, media:
761
762        0x31 (49) = SYSLINUX
763        0x32 (50) = PXELINUX
764        0x33 (51) = ISOLINUX
765        0x34 (52) = EXTLINUX
766
767In recent versions of Linux, this ID is available as
768/proc/sys/kernel/bootloader_type.
769
770
771   ++++ BUG REPORTS ++++
772
773I would appreciate hearing of any problems you have with Syslinux.  I
774would also like to hear from you if you have successfully used Syslinux,
775*especially* if you are using it for a distribution.
776
777If you are reporting problems, please include all possible information
778about your system and your BIOS; the vast majority of all problems
779reported turn out to be BIOS or hardware bugs, and I need as much
780information as possible in order to diagnose the problems.
781
782There is a mailing list for discussion among Syslinux users and for
783announcements of new and test versions.  To join, or to browse the
784archive, go to:
785
786   http://www.zytor.com/mailman/listinfo/syslinux
787
788Please DO NOT send HTML messages or attachments to the mailing list
789(including multipart/alternative or similar.)  All such messages will
790be bounced.
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