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+EXTLINUX is a new syslinux derivative, which boots from a Linux
+ext2/ext3 filesystem.
+It works the same way as SYSLINUX, with a few slight modifications.
+1. The installer is run on a *mounted* filesystem. Run the extlinux
+ installer on the directory in which you want extlinux installed:
+ extlinux --install /boot
+ Specify --install (-i) to install for the first time, or
+ --update (-U) to upgrade a previous installation.
+ NOTE: this doesn't have to be the root directory of a filesystem.
+ If /boot is a filesystem, you can do:
+ mkdir -p /boot/extlinux
+ extlinux --install /boot/extlinux
+ ... to create a subdirectory and install extlinux in it.
+ /boot/extlinux is the recommended location for extlinux.
+2. The configuration file is called "extlinux.conf", and is expected
+ to be found in the same directory as extlinux is installed in.
+3. Pathnames can be absolute or relative; if absolute (with a leading
+ slash), they are relative to the root of the filesystem on which
+ extlinux is installed (/boot in the example above), if relative,
+ they are relative to the extlinux directory.
+ extlinux supports subdirectories, but the total path length is
+ limited to 511 characters.
+4. EXTLINUX now supports symbolic links. However, extremely long
+ symbolic links might hit the pathname limit. Also, please note
+ that absolute symbolic links are interpreted from the root *of the
+ filesystem*, which might be different from now the running system
+ would interpret it (e.g. in the case of a separate /boot
+ partition.) Therefore, use relative symbolic links if at all
+ possible.
+5. EXTLINUX now has "boot-once" support. The boot-once information is
+ stored in an on-disk datastructure, part of extlinux.sys, called
+ the "Auxillary Data Vector". The Auxilliary Data Vector is also
+ available to COMBOOT/COM32 modules that want to store small amounts
+ of information.
+ To set the boot-once information, do:
+ extlinux --once 'command' /boot/extlinux
+ where 'command' is any command you could enter at the SYSLINUX
+ command line. It will be executed on the next boot and then
+ erased.
+ To clear the boot-once information, do:
+ extlinux --clear-once /boot/extlinux
+ If EXTLINUX is used on a RAID-1, this is recommended, since under
+ certain circumstances a RAID-1 rebuild can "resurrect" the
+ boot-once information otherwise.
+ To clear the entire Auxillary Data Vector, do:
+ extlinux --reset-adv /boot/extlinux
+ This will erase all data stored in the ADV, including boot-once.
+ The --once, --clear-once, and --reset-adv commands can be combined
+ with --install or --update, if desired. The ADV is preserved
+ across updates, unless --reset-adv is specified.
+Note that EXTLINUX installs in the filesystem partition like a
+well-behaved bootloader :) Thus, it needs a master boot record in the
+partition table; the mbr.bin shipped with SYSLINUX should work well.
+To install it just do:
+ cat mbr.bin > /dev/XXX
+... where /dev/XXX is the appropriate master device, e.g. /dev/hda,
+and make sure the correct partition in set active.
+If you have multiple disks in a software RAID configuration, the
+preferred way to boot is:
+- Create a separate RAID-1 partition for /boot. Note that the Linux
+ RAID-1 driver can span as many disks as you wish.
+- Install the MBR on *each disk*, and mark the RAID-1 partition
+ active.
+- Run "extlinux -i /boot" to install extlinux. This will install it on
+ all the drives in the RAID-1 set, which means you can boot any
+ combination of drives in any order.
+It is not required to re-run the extlinux installer after installing
+new kernels. If you are using ext3 journalling, however, it might be
+desirable to do so, since running the extlinux installer will flush
+the log. Otherwise a dirty shutdown could cause some of the new
+kernel image to still be in the log. This is a general problem for
+boot loaders on journalling filesystems; it is not specific to
+extlinux. The "sync" command does not flush the log on the ext3
+The SYSLINUX series boot loaders support chain loading other operating
+systems via a separate module, chain.c32 (located in
+com32/modules/chain.c32). To use it, specify a LABEL in the
+configuration file with KERNEL chain.c32 and
+APPEND [hd|fd]<number> [<partition>]
+For example:
+# Windows CE/ME/NT, a very dense operating system.
+# Second partition (2) on the first hard disk (hd0);
+# Linux would *typically* call this /dev/hda2 or /dev/sda2.
+LABEL cement
+ KERNEL chain.c32
+ APPEND hd0 2
+See also README.menu.