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-Table of Contents
-*****************
-
-GNU GRUB manual
-1 Introduction to GRUB
- 1.1 Overview
- 1.2 History of GRUB
- 1.3 GRUB features
- 1.4 The role of a boot loader
-2 Naming convention
-3 Installation
- 3.1 Creating a GRUB boot floppy
- 3.2 Installing GRUB natively
- 3.3 Installing GRUB using grub-install
- 3.4 Making a GRUB bootable CD-ROM
-4 Booting
- 4.1 How to boot operating systems
- 4.1.1 How to boot an OS directly with GRUB
- 4.1.2 Load another boot loader to boot unsupported operating systems
- 4.2 Some caveats on OS-specific issues
- 4.2.1 GNU/Hurd
- 4.2.2 GNU/Linux
- 4.2.3 FreeBSD
- 4.2.4 NetBSD
- 4.2.5 OpenBSD
- 4.2.6 DOS/Windows
- 4.2.7 SCO UnixWare
- 4.2.8 QNX
- 4.3 How to make your system robust
- 4.3.1 Booting once-only
- 4.3.2 Booting fallback systems
-5 Configuration
-6 Downloading OS images from a network
- 6.1 How to set up your network
- 6.2 Booting from a network
-7 Using GRUB via a serial line
-8 Embedding a configuration file into GRUB
-9 Protecting your computer from cracking
-10 GRUB image files
-11 Filesystem syntax and semantics
- 11.1 How to specify devices
- 11.2 How to specify files
- 11.3 How to specify block lists
-12 GRUB's user interface
- 12.1 The flexible command-line interface
- 12.2 The simple menu interface
- 12.3 Editing a menu entry
- 12.4 The hidden menu interface
-13 The list of available commands
- 13.1 The list of commands for the menu only
- 13.1.1 default
- 13.1.2 fallback
- 13.1.3 hiddenmenu
- 13.1.4 timeout
- 13.1.5 title
- 13.2 The list of general commands
- 13.2.1 bootp
- 13.2.2 color
- 13.2.3 device
- 13.2.4 dhcp
- 13.2.5 hide
- 13.2.6 ifconfig
- 13.2.7 pager
- 13.2.8 partnew
- 13.2.9 parttype
- 13.2.10 password
- 13.2.11 rarp
- 13.2.12 serial
- 13.2.13 setkey
- 13.2.14 terminal
- 13.2.15 terminfo
- 13.2.16 tftpserver
- 13.2.17 unhide
- 13.3 The list of command-line and menu entry commands
- 13.3.1 blocklist
- 13.3.2 boot
- 13.3.3 cat
- 13.3.4 chainloader
- 13.3.5 cmp
- 13.3.6 configfile
- 13.3.7 debug
- 13.3.8 displayapm
- 13.3.9 displaymem
- 13.3.10 embed
- 13.3.11 find
- 13.3.12 fstest
- 13.3.13 geometry
- 13.3.14 halt
- 13.3.15 help
- 13.3.16 impsprobe
- 13.3.17 initrd
- 13.3.18 install
- 13.3.19 ioprobe
- 13.3.20 kernel
- 13.3.21 lock
- 13.3.22 makeactive
- 13.3.23 map
- 13.3.24 md5crypt
- 13.3.25 module
- 13.3.26 modulenounzip
- 13.3.27 pause
- 13.3.28 quit
- 13.3.29 reboot
- 13.3.30 read
- 13.3.31 root
- 13.3.32 rootnoverify
- 13.3.33 savedefault
- 13.3.34 setup
- 13.3.35 testload
- 13.3.36 testvbe
- 13.3.37 uppermem
- 13.3.38 vbeprobe
-14 Error messages reported by GRUB
- 14.1 Errors reported by the Stage 1
- 14.2 Errors reported by the Stage 1.5
- 14.3 Errors reported by the Stage 2
-15 Invoking the grub shell
- 15.1 Introduction into the grub shell
- 15.2 How to install GRUB via `grub'
- 15.3 The map between BIOS drives and OS devices
-16 Invoking grub-install
-17 Invoking grub-md5-crypt
-18 Invoking grub-terminfo
-19 Invoking grub-set-default
-20 Invoking mbchk
-Appendix A How to obtain and build GRUB
-Appendix B Reporting bugs
-Appendix C Where GRUB will go
-Appendix D Hacking GRUB
- D.1 The memory map of various components
- D.2 Embedded variables in GRUB
- D.3 The generic interface for filesystems
- D.4 The generic interface for built-ins
- D.5 The bootstrap mechanism used in GRUB
- D.6 How to probe I/O ports used by INT 13H
- D.7 How to detect all installed RAM
- D.8 INT 13H disk I/O interrupts
- D.9 The structure of Master Boot Record
- D.10 The format of partition tables
- D.11 Where and how you should send patches
-Appendix E Copying This Manual
- E.1 GNU Free Documentation License
- E.1.1 ADDENDUM: How to use this License for your documents
-Index
-
-
-GNU GRUB manual
-***************
-
-This is the documentation of GNU GRUB, the GRand Unified Bootloader, a
-flexible and powerful boot loader program for PCs.
-
- This edition documents version 0.97.
-
- This manual is for GNU GRUB (version 0.97, 8 May 2005).
-
- Copyright (C) 1999,2000,2001,2002,2004,2006 Free Software
-Foundation, Inc.
-
- Permission is granted to copy, distribute and/or modify this
- document under the terms of the GNU Free Documentation License,
- Version 1.2 or any later version published by the Free Software
- Foundation; with no Invariant Sections, with the Front-Cover Texts
- being "A GNU Manual," and with the Back-Cover Texts as in (a)
- below. A copy of the license is included in the section entitled
- "GNU Free Documentation License."
-
- (a) The FSF's Back-Cover Text is: "You have freedom to copy and
- modify this GNU Manual, like GNU software. Copies published by
- the Free Software Foundation raise funds for GNU development."
-
-1 Introduction to GRUB
-**********************
-
-1.1 Overview
-============
-
-Briefly, a "boot loader" is the first software program that runs when a
-computer starts. It is responsible for loading and transferring
-control to an operating system "kernel" software (such as Linux or GNU
-Mach). The kernel, in turn, initializes the rest of the operating
-system (e.g. a GNU system).
-
- GNU GRUB is a very powerful boot loader, which can load a wide
-variety of free operating systems, as well as proprietary operating
-systems with chain-loading(1) (*note Overview-Footnote-1::). GRUB is
-designed to address the complexity of booting a personal computer; both
-the program and this manual are tightly bound to that computer platform,
-although porting to other platforms may be addressed in the future.
-
- One of the important features in GRUB is flexibility; GRUB
-understands filesystems and kernel executable formats, so you can load
-an arbitrary operating system the way you like, without recording the
-physical position of your kernel on the disk. Thus you can load the
-kernel just by specifying its file name and the drive and partition
-where the kernel resides.
-
- When booting with GRUB, you can use either a command-line interface
-(*note Command-line interface::), or a menu interface (*note Menu
-interface::). Using the command-line interface, you type the drive
-specification and file name of the kernel manually. In the menu
-interface, you just select an OS using the arrow keys. The menu is
-based on a configuration file which you prepare beforehand (*note
-Configuration::). While in the menu, you can switch to the command-line
-mode, and vice-versa. You can even edit menu entries before using them.
-
- In the following chapters, you will learn how to specify a drive, a
-partition, and a file name (*note Naming convention::) to GRUB, how to
-install GRUB on your drive (*note Installation::), and how to boot your
-OSes (*note Booting::), step by step.
-
- Besides the GRUB boot loader itself, there is a "grub shell" `grub'
-(*note Invoking the grub shell::) which can be run when you are in your
-operating system. It emulates the boot loader and can be used for
-installing the boot loader.
-
- (1) "chain-load" is the mechanism for loading unsupported operating
-systems by loading another boot loader. It is typically used for
-loading DOS or Windows.
-
-1.2 History of GRUB
-===================
-
-GRUB originated in 1995 when Erich Boleyn was trying to boot the GNU
-Hurd with the University of Utah's Mach 4 microkernel (now known as GNU
-Mach). Erich and Brian Ford designed the Multiboot Specification
-(*note Multiboot Specification: (multiboot)Top.), because they were
-determined not to add to the large number of mutually-incompatible PC
-boot methods.
-
- Erich then began modifying the FreeBSD boot loader so that it would
-understand Multiboot. He soon realized that it would be a lot easier to
-write his own boot loader from scratch than to keep working on the
-FreeBSD boot loader, and so GRUB was born.
-
- Erich added many features to GRUB, but other priorities prevented him
-from keeping up with the demands of its quickly-expanding user base. In
-1999, Gordon Matzigkeit and Yoshinori K. Okuji adopted GRUB as an
-official GNU package, and opened its development by making the latest
-sources available via anonymous CVS. *Note Obtaining and Building
-GRUB::, for more information.
-
-1.3 GRUB features
-=================
-
-The primary requirement for GRUB is that it be compliant with the
-"Multiboot Specification", which is described in *Note Multiboot
-Specification: (multiboot)Top.
-
- The other goals, listed in approximate order of importance, are:
-
- * Basic functions must be straightforward for end-users.
-
- * Rich functionality to support kernel experts and designers.
-
- * Backward compatibility for booting FreeBSD, NetBSD, OpenBSD, and
- Linux. Proprietary kernels (such as DOS, Windows NT, and OS/2) are
- supported via a chain-loading function.
-
- Except for specific compatibility modes (chain-loading and the Linux
-"piggyback" format), all kernels will be started in much the same state
-as in the Multiboot Specification. Only kernels loaded at 1 megabyte or
-above are presently supported. Any attempt to load below that boundary
-will simply result in immediate failure and an error message reporting
-the problem.
-
- In addition to the requirements above, GRUB has the following
-features (note that the Multiboot Specification doesn't require all the
-features that GRUB supports):
-
-Recognize multiple executable formats
- Support many of the "a.out" variants plus "ELF". Symbol tables are
- also loaded.
-
-Support non-Multiboot kernels
- Support many of the various free 32-bit kernels that lack Multiboot
- compliance (primarily FreeBSD, NetBSD, OpenBSD, and Linux).
- Chain-loading of other boot loaders is also supported.
-
-Load multiples modules
- Fully support the Multiboot feature of loading multiple modules.
-
-Load a configuration file
- Support a human-readable text configuration file with preset boot
- commands. You can also load another configuration file dynamically
- and embed a preset configuration file in a GRUB image file. The
- list of commands (*note Commands::) are a superset of those
- supported on the command-line. An example configuration file is
- provided in *Note Configuration::.
-
-Provide a menu interface
- A menu interface listing preset boot commands, with a programmable
- timeout, is available. There is no fixed limit on the number of
- boot entries, and the current implementation has space for several
- hundred.
-
-Have a flexible command-line interface
- A fairly flexible command-line interface, accessible from the menu,
- is available to edit any preset commands, or write a new boot
- command set from scratch. If no configuration file is present,
- GRUB drops to the command-line.
-
- The list of commands (*note Commands::) are a subset of those
- supported for configuration files. Editing commands closely
- resembles the Bash command-line (*note Bash: (features)Command
- Line Editing.), with <TAB>-completion of commands, devices,
- partitions, and files in a directory depending on context.
-
-Support multiple filesystem types
- Support multiple filesystem types transparently, plus a useful
- explicit blocklist notation. The currently supported filesystem
- types are "BSD FFS", "DOS FAT16 and FAT32", "Minix fs", "Linux
- ext2fs", "ReiserFS", "JFS", "XFS", and "VSTa fs". *Note
- Filesystem::, for more information.
-
-Support automatic decompression
- Can decompress files which were compressed by `gzip'. This
- function is both automatic and transparent to the user (i.e. all
- functions operate upon the uncompressed contents of the specified
- files). This greatly reduces a file size and loading time, a
- particularly great benefit for floppies.(1) (*note
- Features-Footnote-1::)
-
- It is conceivable that some kernel modules should be loaded in a
- compressed state, so a different module-loading command can be
- specified to avoid uncompressing the modules.
-
-Access data on any installed device
- Support reading data from any or all floppies or hard disk(s)
- recognized by the BIOS, independent of the setting of the root
- device.
-
-Be independent of drive geometry translations
- Unlike many other boot loaders, GRUB makes the particular drive
- translation irrelevant. A drive installed and running with one
- translation may be converted to another translation without any
- adverse effects or changes in GRUB's configuration.
-
-Detect all installed RAM
- GRUB can generally find all the installed RAM on a PC-compatible
- machine. It uses an advanced BIOS query technique for finding all
- memory regions. As described on the Multiboot Specification (*note
- Multiboot Specification: (multiboot)Top.), not all kernels make
- use of this information, but GRUB provides it for those who do.
-
-Support Logical Block Address mode
- In traditional disk calls (called "CHS mode"), there is a geometry
- translation problem, that is, the BIOS cannot access over 1024
- cylinders, so the accessible space is limited to at least 508 MB
- and to at most 8GB. GRUB can't universally solve this problem, as
- there is no standard interface used in all machines. However,
- several newer machines have the new interface, Logical Block
- Address ("LBA") mode. GRUB automatically detects if LBA mode is
- available and uses it if available. In LBA mode, GRUB can access
- the entire disk.
-
-Support network booting
- GRUB is basically a disk-based boot loader but also has network
- support. You can load OS images from a network by using the "TFTP"
- protocol.
-
-Support remote terminals
- To support computers with no console, GRUB provides remote terminal
- support, so that you can control GRUB from a remote host. Only
- serial terminal support is implemented at the moment.
-
- (1) There are a few pathological cases where loading a very badly
-organized ELF kernel might take longer, but in practice this never
-happen.
-
-1.4 The role of a boot loader
-=============================
-
-The following is a quotation from Gordon Matzigkeit, a GRUB fanatic:
-
- Some people like to acknowledge both the operating system and
- kernel when they talk about their computers, so they might say
- they use "GNU/Linux" or "GNU/Hurd". Other people seem to think
- that the kernel is the most important part of the system, so they
- like to call their GNU operating systems "Linux systems."
-
- I, personally, believe that this is a grave injustice, because the
- _boot loader_ is the most important software of all. I used to
- refer to the above systems as either "LILO"(1) (*note Role of a
- boot loader-Footnote-1::) or "GRUB" systems.
-
- Unfortunately, nobody ever understood what I was talking about;
- now I just use the word "GNU" as a pseudonym for GRUB.
-
- So, if you ever hear people talking about their alleged "GNU"
- systems, remember that they are actually paying homage to the best
- boot loader around... GRUB!
-
- We, the GRUB maintainers, do not (usually) encourage Gordon's level
-of fanaticism, but it helps to remember that boot loaders deserve
-recognition. We hope that you enjoy using GNU GRUB as much as we did
-writing it.
-
- (1) The LInux LOader, a boot loader that everybody uses, but nobody
-likes.
-
-2 Naming convention
-*******************
-
-The device syntax used in GRUB is a wee bit different from what you may
-have seen before in your operating system(s), and you need to know it so
-that you can specify a drive/partition.
-
- Look at the following examples and explanations:
-
- (fd0)
-
- First of all, GRUB requires that the device name be enclosed with
-`(' and `)'. The `fd' part means that it is a floppy disk. The number
-`0' is the drive number, which is counted from _zero_. This expression
-means that GRUB will use the whole floppy disk.
-
- (hd0,1)
-
- Here, `hd' means it is a hard disk drive. The first integer `0'
-indicates the drive number, that is, the first hard disk, while the
-second integer, `1', indicates the partition number (or the PC slice
-number in the BSD terminology). Once again, please note that the
-partition numbers are counted from _zero_, not from one. This
-expression means the second partition of the first hard disk drive. In
-this case, GRUB uses one partition of the disk, instead of the whole
-disk.
-
- (hd0,4)
-
- This specifies the first "extended partition" of the first hard disk
-drive. Note that the partition numbers for extended partitions are
-counted from `4', regardless of the actual number of primary partitions
-on your hard disk.
-
- (hd1,a)
-
- This means the BSD `a' partition of the second hard disk. If you
-need to specify which PC slice number should be used, use something
-like this: `(hd1,0,a)'. If the PC slice number is omitted, GRUB
-searches for the first PC slice which has a BSD `a' partition.
-
- Of course, to actually access the disks or partitions with GRUB, you
-need to use the device specification in a command, like `root (fd0)' or
-`unhide (hd0,2)'. To help you find out which number specifies a
-partition you want, the GRUB command-line (*note Command-line
-interface::) options have argument completion. This means that, for
-example, you only need to type
-
- root (
-
- followed by a <TAB>, and GRUB will display the list of drives,
-partitions, or file names. So it should be quite easy to determine the
-name of your target partition, even with minimal knowledge of the
-syntax.
-
- Note that GRUB does _not_ distinguish IDE from SCSI - it simply
-counts the drive numbers from zero, regardless of their type. Normally,
-any IDE drive number is less than any SCSI drive number, although that
-is not true if you change the boot sequence by swapping IDE and SCSI
-drives in your BIOS.
-
- Now the question is, how to specify a file? Again, consider an
-example:
-
- (hd0,0)/vmlinuz
-
- This specifies the file named `vmlinuz', found on the first
-partition of the first hard disk drive. Note that the argument
-completion works with file names, too.
-
- That was easy, admit it. Now read the next chapter, to find out how
-to actually install GRUB on your drive.
-
-3 Installation
-**************
-
-In order to install GRUB as your boot loader, you need to first install
-the GRUB system and utilities under your UNIX-like operating system
-(*note Obtaining and Building GRUB::). You can do this either from the
-source tarball, or as a package for your OS.
-
- After you have done that, you need to install the boot loader on a
-drive (floppy or hard disk). There are two ways of doing that - either
-using the utility `grub-install' (*note Invoking grub-install::) on a
-UNIX-like OS, or by running GRUB itself from a floppy. These are quite
-similar, however the utility might probe a wrong BIOS drive, so you
-should be careful.
-
- Also, if you install GRUB on a UNIX-like OS, please make sure that
-you have an emergency boot disk ready, so that you can rescue your
-computer if, by any chance, your hard drive becomes unusable
-(unbootable).
-
- GRUB comes with boot images, which are normally put in the directory
-`/usr/lib/grub/i386-pc'. If you do not use grub-install, then you need
-to copy the files `stage1', `stage2', and `*stage1_5' to the directory
-`/boot/grub', and run the `grub-set-default' (*note Invoking
-grub-set-default::) if you intend to use `default saved' (*note
-default::) in your configuration file. Hereafter, the directory where
-GRUB images are initially placed (normally `/usr/lib/grub/i386-pc')
-will be called the "image directory", and the directory where the boot
-loader needs to find them (usually `/boot/grub') will be called the
-"boot directory".
-
-3.1 Creating a GRUB boot floppy
-===============================
-
-To create a GRUB boot floppy, you need to take the files `stage1' and
-`stage2' from the image directory, and write them to the first and the
-second block of the floppy disk, respectively.
-
- *Caution:* This procedure will destroy any data currently stored on
-the floppy.
-
- On a UNIX-like operating system, that is done with the following
-commands:
-
- # cd /usr/lib/grub/i386-pc
- # dd if=stage1 of=/dev/fd0 bs=512 count=1
- 1+0 records in
- 1+0 records out
- # dd if=stage2 of=/dev/fd0 bs=512 seek=1
- 153+1 records in
- 153+1 records out
- #
-
- The device file name may be different. Consult the manual for your
-OS.
-
-3.2 Installing GRUB natively
-============================
-
-*Caution:* Installing GRUB's stage1 in this manner will erase the
-normal boot-sector used by an OS.
-
- GRUB can currently boot GNU Mach, Linux, FreeBSD, NetBSD, and OpenBSD
-directly, so using it on a boot sector (the first sector of a
-partition) should be okay. But generally, it would be a good idea to
-back up the first sector of the partition on which you are installing
-GRUB's stage1. This isn't as important if you are installing GRUB on
-the first sector of a hard disk, since it's easy to reinitialize it
-(e.g. by running `FDISK /MBR' from DOS).
-
- If you decide to install GRUB in the native environment, which is
-definitely desirable, you'll need to create a GRUB boot disk, and
-reboot your computer with it. Otherwise, see *Note Installing GRUB
-using grub-install::.
-
- Once started, GRUB will show the command-line interface (*note
-Command-line interface::). First, set the GRUB's "root device"(1)
-(*note Installing GRUB natively-Footnote-1::) to the partition
-containing the boot directory, like this:
-
- grub> root (hd0,0)
-
- If you are not sure which partition actually holds this directory,
-use the command `find' (*note find::), like this:
-
- grub> find /boot/grub/stage1
-
- This will search for the file name `/boot/grub/stage1' and show the
-devices which contain the file.
-
- Once you've set the root device correctly, run the command `setup'
-(*note setup::):
-
- grub> setup (hd0)
-
- This command will install the GRUB boot loader on the Master Boot
-Record (MBR) of the first drive. If you want to put GRUB into the boot
-sector of a partition instead of putting it in the MBR, specify the
-partition into which you want to install GRUB:
-
- grub> setup (hd0,0)
-
- If you install GRUB into a partition or a drive other than the first
-one, you must chain-load GRUB from another boot loader. Refer to the
-manual for the boot loader to know how to chain-load GRUB.
-
- After using the setup command, you will boot into GRUB without the
-GRUB floppy. See the chapter *Note Booting:: to find out how to boot
-your operating systems from GRUB.
-
- (1) Note that GRUB's root device doesn't necessarily mean your OS's
-root partition; if you need to specify a root partition for your OS,
-add the argument into the command `kernel'.
-
-3.3 Installing GRUB using grub-install
-======================================
-
-*Caution:* This procedure is definitely less safe, because there are
-several ways in which your computer can become unbootable. For example,
-most operating systems don't tell GRUB how to map BIOS drives to OS
-devices correctly--GRUB merely "guesses" the mapping. This will succeed
-in most cases, but not always. Therefore, GRUB provides you with a map
-file called the "device map", which you must fix if it is wrong. *Note
-Device map::, for more details.
-
- If you still do want to install GRUB under a UNIX-like OS (such as
-GNU), invoke the program `grub-install' (*note Invoking grub-install::)
-as the superuser ("root").
-
- The usage is basically very simple. You only need to specify one
-argument to the program, namely, where to install the boot loader. The
-argument can be either a device file (like `/dev/hda') or a partition
-specified in GRUB's notation. For example, under Linux the following
-will install GRUB into the MBR of the first IDE disk:
-
- # grub-install /dev/hda
-
- Likewise, under GNU/Hurd, this has the same effect:
-
- # grub-install /dev/hd0
-
- If it is the first BIOS drive, this is the same as well:
-
- # grub-install '(hd0)'
-
- Or you can omit the parentheses:
-
- # grub-install hd0
-
- But all the above examples assume that GRUB should use images under
-the root directory. If you want GRUB to use images under a directory
-other than the root directory, you need to specify the option
-`--root-directory'. The typical usage is that you create a GRUB boot
-floppy with a filesystem. Here is an example:
-
- # mke2fs /dev/fd0
- # mount -t ext2 /dev/fd0 /mnt
- # grub-install --root-directory=/mnt fd0
- # umount /mnt
-
- Another example is when you have a separate boot partition which is
-mounted at `/boot'. Since GRUB is a boot loader, it doesn't know
-anything about mountpoints at all. Thus, you need to run `grub-install'
-like this:
-
- # grub-install --root-directory=/boot /dev/hda
-
- By the way, as noted above, it is quite difficult to guess BIOS
-drives correctly under a UNIX-like OS. Thus, `grub-install' will prompt
-you to check if it could really guess the correct mappings, after the
-installation. The format is defined in *Note Device map::. Please be
-quite careful. If the output is wrong, it is unlikely that your
-computer will be able to boot with no problem.
-
- Note that `grub-install' is actually just a shell script and the
-real task is done by the grub shell `grub' (*note Invoking the grub
-shell::). Therefore, you may run `grub' directly to install GRUB,
-without using `grub-install'. Don't do that, however, unless you are
-very familiar with the internals of GRUB. Installing a boot loader on a
-running OS may be extremely dangerous.
-
-3.4 Making a GRUB bootable CD-ROM
-=================================
-
-GRUB supports the "no emulation mode" in the El Torito specification(1)
-(*note Making a GRUB bootable CD-ROM-Footnote-1::). This means that you
-can use the whole CD-ROM from GRUB and you don't have to make a floppy
-or hard disk image file, which can cause compatibility problems.
-
- For booting from a CD-ROM, GRUB uses a special Stage 2 called
-`stage2_eltorito'. The only GRUB files you need to have in your
-bootable CD-ROM are this `stage2_eltorito' and optionally a config file
-`menu.lst'. You don't need to use `stage1' or `stage2', because El
-Torito is quite different from the standard boot process.
-
- Here is an example of procedures to make a bootable CD-ROM image.
-First, make a top directory for the bootable image, say, `iso':
-
- $ mkdir iso
-
- Make a directory for GRUB:
-
- $ mkdir -p iso/boot/grub
-
- Copy the file `stage2_eltorito':
-
- $ cp /usr/lib/grub/i386-pc/stage2_eltorito iso/boot/grub
-
- If desired, make the config file `menu.lst' under `iso/boot/grub'
-(*note Configuration::), and copy any files and directories for the
-disc to the directory `iso/'.
-
- Finally, make a ISO9660 image file like this:
-
- $ mkisofs -R -b boot/grub/stage2_eltorito -no-emul-boot \
- -boot-load-size 4 -boot-info-table -o grub.iso iso
-
- This produces a file named `grub.iso', which then can be burned into
-a CD (or a DVD). `mkisofs' has already set up the disc to boot from
-the `boot/grub/stage2_eltorito' file, so there is no need to setup GRUB
-on the disc. (Note that the `-boot-load-size 4' bit is required for
-compatibility with the BIOS on many older machines.)
-
- You can use the device `(cd)' to access a CD-ROM in your config
-file. This is not required; GRUB automatically sets the root device to
-`(cd)' when booted from a CD-ROM. It is only necessary to refer to
-`(cd)' if you want to access other drives as well.
-
- (1) El Torito is a specification for bootable CD using BIOS
-functions.
-
-4 Booting
-*********
-
-GRUB can load Multiboot-compliant kernels in a consistent way, but for
-some free operating systems you need to use some OS-specific magic.
-
-4.1 How to boot operating systems
-=================================
-
-GRUB has two distinct boot methods. One of the two is to load an
-operating system directly, and the other is to chain-load another boot
-loader which then will load an operating system actually. Generally
-speaking, the former is more desirable, because you don't need to
-install or maintain other boot loaders and GRUB is flexible enough to
-load an operating system from an arbitrary disk/partition. However, the
-latter is sometimes required, since GRUB doesn't support all the
-existing operating systems natively.
-
-4.1.1 How to boot an OS directly with GRUB
-------------------------------------------
-
-Multiboot (*note Multiboot Specification: (multiboot)Top.) is the
-native format supported by GRUB. For the sake of convenience, there is
-also support for Linux, FreeBSD, NetBSD and OpenBSD. If you want to
-boot other operating systems, you will have to chain-load them (*note
-Chain-loading::).
-
- Generally, GRUB can boot any Multiboot-compliant OS in the following
-steps:
-
- 1. Set GRUB's root device to the drive where the OS images are stored
- with the command `root' (*note root::).
-
- 2. Load the kernel image with the command `kernel' (*note kernel::).
-
- 3. If you need modules, load them with the command `module' (*note
- module::) or `modulenounzip' (*note modulenounzip::).
-
- 4. Run the command `boot' (*note boot::).
-
- Linux, FreeBSD, NetBSD and OpenBSD can be booted in a similar
-manner. You load a kernel image with the command `kernel' and then run
-the command `boot'. If the kernel requires some parameters, just append
-the parameters to `kernel', after the file name of the kernel. Also,
-please refer to *Note OS-specific notes::, for information on your
-OS-specific issues.
-
-4.1.2 Load another boot loader to boot unsupported operating systems
---------------------------------------------------------------------
-
-If you want to boot an unsupported operating system (e.g. Windows 95),
-chain-load a boot loader for the operating system. Normally, the boot
-loader is embedded in the "boot sector" of the partition on which the
-operating system is installed.
-
- 1. Set GRUB's root device to the partition by the command
- `rootnoverify' (*note rootnoverify::):
-
- grub> rootnoverify (hd0,0)
-
- 2. Set the "active" flag in the partition using the command
- `makeactive'(1) (*note Chain-loading-Footnote-1::) (*note
- makeactive::):
-
- grub> makeactive
-
- 3. Load the boot loader with the command `chainloader' (*note
- chainloader::):
-
- grub> chainloader +1
-
- `+1' indicates that GRUB should read one sector from the start of
- the partition. The complete description about this syntax can be
- found in *Note Block list syntax::.
-
- 4. Run the command `boot' (*note boot::).
-
- However, DOS and Windows have some deficiencies, so you might have to
-use more complicated instructions. *Note DOS/Windows::, for more
-information.
-
- (1) This is not necessary for most of the modern operating systems.
-
-4.2 Some caveats on OS-specific issues
-======================================
-
-Here, we describe some caveats on several operating systems.
-
-4.2.1 GNU/Hurd
---------------
-
-Since GNU/Hurd is Multiboot-compliant, it is easy to boot it; there is
-nothing special about it. But do not forget that you have to specify a
-root partition to the kernel.
-
- 1. Set GRUB's root device to the same drive as GNU/Hurd's. Probably
- the command `find /boot/gnumach' or similar can help you (*note
- find::).
-
- 2. Load the kernel and the module, like this:
-
- grub> kernel /boot/gnumach root=hd0s1
- grub> module /boot/serverboot
-
- 3. Run the command `boot' (*note boot::).
-
-4.2.2 GNU/Linux
----------------
-
-It is relatively easy to boot GNU/Linux from GRUB, because it somewhat
-resembles to boot a Multiboot-compliant OS.
-
- 1. Set GRUB's root device to the same drive as GNU/Linux's. Probably
- the command `find /vmlinuz' or similar can help you (*note find::).
-
- 2. Load the kernel:
-
- grub> kernel /vmlinuz root=/dev/hda1
-
- If you need to specify some kernel parameters, just append them to
- the command. For example, to set `vga' to `ext', do this:
-
- grub> kernel /vmlinuz root=/dev/hda1 vga=ext
-
- See the documentation in the Linux source tree for complete
- information on the available options.
-
- 3. If you use an initrd, execute the command `initrd' (*note
- initrd::) after `kernel':
-
- grub> initrd /initrd
-
- 4. Finally, run the command `boot' (*note boot::).
-
- *Caution:* If you use an initrd and specify the `mem=' option to the
-kernel to let it use less than actual memory size, you will also have
-to specify the same memory size to GRUB. To let GRUB know the size, run
-the command `uppermem' _before_ loading the kernel. *Note uppermem::,
-for more information.
-
-4.2.3 FreeBSD
--------------
-
-GRUB can load the kernel directly, either in ELF or a.out format. But
-this is not recommended, since FreeBSD's bootstrap interface sometimes
-changes heavily, so GRUB can't guarantee to pass kernel parameters
-correctly.
-
- Thus, we'd recommend loading the very flexible loader `/boot/loader'
-instead. See this example:
-
- grub> root (hd0,a)
- grub> kernel /boot/loader
- grub> boot
-
-4.2.4 NetBSD
-------------
-
-GRUB can load NetBSD a.out and ELF directly, follow these steps:
-
- 1. Set GRUB's root device with `root' (*note root::).
-
- 2. Load the kernel with `kernel' (*note kernel::). You should append
- the ugly option `--type=netbsd', if you want to load an ELF
- kernel, like this:
-
- grub> kernel --type=netbsd /netbsd-elf
-
- 3. Run `boot' (*note boot::).
-
- For now, however, GRUB doesn't allow you to pass kernel parameters,
-so it may be better to chain-load it instead. For more information,
-please see *Note Chain-loading::.
-
-4.2.5 OpenBSD
--------------
-
-The booting instruction is exactly the same as for NetBSD (*note
-NetBSD::).
-
-4.2.6 DOS/Windows
------------------
-
-GRUB cannot boot DOS or Windows directly, so you must chain-load them
-(*note Chain-loading::). However, their boot loaders have some critical
-deficiencies, so it may not work to just chain-load them. To overcome
-the problems, GRUB provides you with two helper functions.
-
- If you have installed DOS (or Windows) on a non-first hard disk, you
-have to use the disk swapping technique, because that OS cannot boot
-from any disks but the first one. The workaround used in GRUB is the
-command `map' (*note map::), like this:
-
- grub> map (hd0) (hd1)
- grub> map (hd1) (hd0)
-
- This performs a "virtual" swap between your first and second hard
-drive.
-
- *Caution:* This is effective only if DOS (or Windows) uses BIOS to
-access the swapped disks. If that OS uses a special driver for the
-disks, this probably won't work.
-
- Another problem arises if you installed more than one set of
-DOS/Windows onto one disk, because they could be confused if there are
-more than one primary partitions for DOS/Windows. Certainly you should
-avoid doing this, but there is a solution if you do want to do so. Use
-the partition hiding/unhiding technique.
-
- If GRUB "hide"s a DOS (or Windows) partition (*note hide::), DOS (or
-Windows) will ignore the partition. If GRUB "unhide"s a DOS (or
-Windows) partition (*note unhide::), DOS (or Windows) will detect the
-partition. Thus, if you have installed DOS (or Windows) on the first
-and the second partition of the first hard disk, and you want to boot
-the copy on the first partition, do the following:
-
- grub> unhide (hd0,0)
- grub> hide (hd0,1)
- grub> rootnoverify (hd0,0)
- grub> chainloader +1
- grub> makeactive
- grub> boot
-
-4.2.7 SCO UnixWare
-------------------
-
-It is known that the signature in the boot loader for SCO UnixWare is
-wrong, so you will have to specify the option `--force' to
-`chainloader' (*note chainloader::), like this:
-
- grub> rootnoverify (hd1,0)
- grub> chainloader --force +1
- grub> makeactive
- grub> boot
-
-4.2.8 QNX
----------
-
-QNX seems to use a bigger boot loader, so you need to boot it up, like
-this:
-
- grub> rootnoverify (hd1,1)
- grub> chainloader +4
- grub> boot
-
-4.3 How to make your system robust
-==================================
-
-When you test a new kernel or a new OS, it is important to make sure
-that your computer can boot even if the new system is unbootable. This
-is crucial especially if you maintain servers or remote systems. To
-accomplish this goal, you need to set up two things:
-
- 1. You must maintain a system which is always bootable. For instance,
- if you test a new kernel, you need to keep a working kernel in a
- different place. And, it would sometimes be very nice to even have
- a complete copy of a working system in a different partition or
- disk.
-
- 2. You must direct GRUB to boot a working system when the new system
- fails. This is possible with the "fallback" system in GRUB.
-
- The former requirement is very specific to each OS, so this
-documentation does not cover that topic. It is better to consult some
-backup tools.
-
- So let's see the GRUB part. There are two possibilities: one of them
-is quite simple but not very robust, and the other is a bit complex to
-set up but probably the best solution to make sure that your system can
-start as long as GRUB itself is bootable.
-
-4.3.1 Booting once-only
------------------------
-
-You can teach GRUB to boot an entry only at next boot time. Suppose
-that your have an old kernel `old_kernel' and a new kernel
-`new_kernel'. You know that `old_kernel' can boot your system
-correctly, and you want to test `new_kernel'.
-
- To ensure that your system will go back to the old kernel even if the
-new kernel fails (e.g. it panics), you can specify that GRUB should try
-the new kernel only once and boot the old kernel after that.
-
- First, modify your configuration file. Here is an example:
-
- default saved # This is important!!!
- timeout 10
-
- title the old kernel
- root (hd0,0)
- kernel /old_kernel
- savedefault
-
- title the new kernel
- root (hd0,0)
- kernel /new_kernel
- savedefault 0 # This is important!!!
-
- Note that this configuration file uses `default saved' (*note
-default::) at the head and `savedefault 0' (*note savedefault::) in the
-entry for the new kernel. This means that GRUB boots a saved entry by
-default, and booting the entry for the new kernel saves `0' as the
-saved entry.
-
- With this configuration file, after all, GRUB always tries to boot
-the old kernel after it booted the new one, because `0' is the entry of
-`the old kernel'.
-
- The next step is to tell GRUB to boot the new kernel at next boot
-time. For this, execute `grub-set-default' (*note Invoking
-grub-set-default::):
-
- # grub-set-default 1
-
- This command sets the saved entry to `1', that is, to the new kernel.
-
- This method is useful, but still not very robust, because GRUB stops
-booting, if there is any error in the boot entry, such that the new
-kernel has an invalid executable format. Thus, it it even better to use
-the "fallback" mechanism of GRUB. Look at next subsection for this
-feature.
-
-4.3.2 Booting fallback systems
-------------------------------
-
-GRUB supports a fallback mechanism of booting one or more other entries
-if a default boot entry fails. You can specify multiple fallback
-entries if you wish.
-
- Suppose that you have three systems, `A', `B' and `C'. `A' is a
-system which you want to boot by default. `B' is a backup system which
-is supposed to boot safely. `C' is another backup system which is used
-in case where `B' is broken.
-
- Then you may want GRUB to boot the first system which is bootable
-among `A', `B' and `C'. A configuration file can be written in this way:
-
- default saved # This is important!!!
- timeout 10
- fallback 1 2 # This is important!!!
-
- title A
- root (hd0,0)
- kernel /kernel
- savedefault fallback # This is important!!!
-
- title B
- root (hd1,0)
- kernel /kernel
- savedefault fallback # This is important!!!
-
- title C
- root (hd2,0)
- kernel /kernel
- savedefault
-
- Note that `default saved' (*note default::), `fallback 1 2' and
-`savedefault fallback' are used. GRUB will boot a saved entry by
-default and save a fallback entry as next boot entry with this
-configuration.
-
- When GRUB tries to boot `A', GRUB saves `1' as next boot entry,
-because the command `fallback' specifies that `1' is the first fallback
-entry. The entry `1' is `B', so GRUB will try to boot `B' at next boot
-time.
-
- Likewise, when GRUB tries to boot `B', GRUB saves `2' as next boot
-entry, because `fallback' specifies `2' as next fallback entry. This
-makes sure that GRUB will boot `C' after booting `B'.
-
- It is noteworthy that GRUB uses fallback entries both when GRUB
-itself fails in booting an entry and when `A' or `B' fails in starting
-up your system. So this solution ensures that your system is started
-even if GRUB cannot find your kernel or if your kernel panics.
-
- However, you need to run `grub-set-default' (*note Invoking
-grub-set-default::) when `A' starts correctly or you fix `A' after it
-crashes, since GRUB always sets next boot entry to a fallback entry.
-You should run this command in a startup script such as `rc.local' to
-boot `A' by default:
-
- # grub-set-default 0
-
- where `0' is the number of the boot entry for the system `A'.
-
- If you want to see what is current default entry, you can look at the
-file `/boot/grub/default' (or `/grub/default' in some systems). Because
-this file is plain-text, you can just `cat' this file. But it is
-strongly recommended *not to modify this file directly*, because GRUB
-may fail in saving a default entry in this file, if you change this
-file in an unintended manner. Therefore, you should use
-`grub-set-default' when you need to change the default entry.
-
-5 Configuration
-***************
-
-You've probably noticed that you need to type several commands to boot
-your OS. There's a solution to that - GRUB provides a menu interface
-(*note Menu interface::) from which you can select an item (using arrow
-keys) that will do everything to boot an OS.
-
- To enable the menu, you need a configuration file, `menu.lst' under
-the boot directory. We'll analyze an example file.
-
- The file first contains some general settings, the menu interface
-related options. You can put these commands (*note Menu-specific
-commands::) before any of the items (starting with `title' (*note
-title::)).
-
- #
- # Sample boot menu configuration file
- #
-
- As you may have guessed, these lines are comments. Lines starting
-with a hash character (`#'), and blank lines, are ignored by GRUB.
-
- # By default, boot the first entry.
- default 0
-
- The first entry (here, counting starts with number zero, not one!)
-will be the default choice.
-
- # Boot automatically after 30 secs.
- timeout 30
-
- As the comment says, GRUB will boot automatically in 30 seconds,
-unless interrupted with a keypress.
-
- # Fallback to the second entry.
- fallback 1
-
- If, for any reason, the default entry doesn't work, fall back to the
-second one (this is rarely used, for obvious reasons).
-
- Note that the complete descriptions of these commands, which are menu
-interface specific, can be found in *Note Menu-specific commands::.
-Other descriptions can be found in *Note Commands::.
-
- Now, on to the actual OS definitions. You will see that each entry
-begins with a special command, `title' (*note title::), and the action
-is described after it. Note that there is no command `boot' (*note
-boot::) at the end of each item. That is because GRUB automatically
-executes `boot' if it loads other commands successfully.
-
- The argument for the command `title' is used to display a short
-title/description of the entry in the menu. Since `title' displays the
-argument as is, you can write basically anything there.
-
- # For booting GNU/Hurd
- title GNU/Hurd
- root (hd0,0)
- kernel /boot/gnumach.gz root=hd0s1
- module /boot/serverboot.gz
-
- This boots GNU/Hurd from the first hard disk.
-
- # For booting GNU/Linux
- title GNU/Linux
- kernel (hd1,0)/vmlinuz root=/dev/hdb1
-
- This boots GNU/Linux, but from the second hard disk.
-
- # For booting Mach (getting kernel from floppy)
- title Utah Mach4 multiboot
- root (hd0,2)
- pause Insert the diskette now^G!!
- kernel (fd0)/boot/kernel root=hd0s3
- module (fd0)/boot/bootstrap
-
- This boots Mach with a kernel on a floppy, but the root filesystem at
-hd0s3. It also contains a `pause' line (*note pause::), which will
-cause GRUB to display a prompt and delay, before actually executing the
-rest of the commands and booting.
-
- # For booting FreeBSD
- title FreeBSD
- root (hd0,2,a)
- kernel /boot/loader
-
- This item will boot FreeBSD kernel loaded from the `a' partition of
-the third PC slice of the first hard disk.
-
- # For booting OS/2
- title OS/2
- root (hd0,1)
- makeactive
- # chainload OS/2 bootloader from the first sector
- chainloader +1
- # This is similar to "chainload", but loads a specific file
- #chainloader /boot/chain.os2
-
- This will boot OS/2, using a chain-loader (*note Chain-loading::).
-
- # For booting Windows NT or Windows95
- title Windows NT / Windows 95 boot menu
- root (hd0,0)
- makeactive
- chainloader +1
- # For loading DOS if Windows NT is installed
- # chainload /bootsect.dos
-
- The same as the above, but for Windows.
-
- # For installing GRUB into the hard disk
- title Install GRUB into the hard disk
- root (hd0,0)
- setup (hd0)
-
- This will just (re)install GRUB onto the hard disk.
-
- # Change the colors.
- title Change the colors
- color light-green/brown blink-red/blue
-
- In the last entry, the command `color' is used (*note color::), to
-change the menu colors (try it!). This command is somewhat special,
-because it can be used both in the command-line and in the menu. GRUB
-has several such commands, see *Note General commands::.
-
- We hope that you now understand how to use the basic features of
-GRUB. To learn more about GRUB, see the following chapters.
-
-6 Downloading OS images from a network
-**************************************
-
-Although GRUB is a disk-based boot loader, it does provide network
-support. To use the network support, you need to enable at least one
-network driver in the GRUB build process. For more information please
-see `netboot/README.netboot' in the source distribution.
-
-6.1 How to set up your network
-==============================
-
-GRUB requires a file server and optionally a server that will assign an
-IP address to the machine on which GRUB is running. For the former, only
-TFTP is supported at the moment. The latter is either BOOTP, DHCP or a
-RARP server(1) (*note General usage of network support-Footnote-1::).
-It is not necessary to run both the servers on one computer. How to
-configure these servers is beyond the scope of this document, so please
-refer to the manuals specific to those protocols/servers.
-
- If you decided to use a server to assign an IP address, set up the
-server and run `bootp' (*note bootp::), `dhcp' (*note dhcp::) or `rarp'
-(*note rarp::) for BOOTP, DHCP or RARP, respectively. Each command will
-show an assigned IP address, a netmask, an IP address for your TFTP
-server and a gateway. If any of the addresses is wrong or it causes an
-error, probably the configuration of your servers isn't set up properly.
-
- Otherwise, run `ifconfig', like this:
-
- grub> ifconfig --address=192.168.110.23 --server=192.168.110.14
-
- You can also use `ifconfig' in conjuction with `bootp', `dhcp' or
-`rarp' (e.g. to reassign the server address manually). *Note
-ifconfig::, for more details.
-
- Finally, download your OS images from your network. The network can
-be accessed using the network drive `(nd)'. Everything else is very
-similar to the normal instructions (*note Booting::).
-
- Here is an example:
-
- grub> bootp
- Probing... [NE*000]
- NE2000 base ...
- Address: 192.168.110.23 Netmask: 255.255.255.0
- Server: 192.168.110.14 Gateway: 192.168.110.1
-
- grub> root (nd)
- grub> kernel /tftproot/gnumach.gz root=sd0s1
- grub> module /tftproot/serverboot.gz
- grub> boot
-
- (1) RARP is not advised, since it cannot serve much information
-
-6.2 Booting from a network
-==========================
-
-It is sometimes very useful to boot from a network, especially when you
-use a machine which has no local disk. In this case, you need to obtain
-a kind of Net Boot ROM, such as a PXE ROM or a free software package
-like Etherboot. Such a Boot ROM first boots the machine, sets up the
-network card installed into the machine, and downloads a second stage
-boot image from the network. Then, the second image will try to boot an
-operating system actually from the network.
-
- GRUB provides two second stage images, `nbgrub' and `pxegrub' (*note
-Images::). These images are the same as the normal Stage 2, except that
-they set up a network automatically, and try to load a configuration
-file from the network, if specified. The usage is very simple: If the
-machine has a PXE ROM, use `pxegrub'. If the machine has an NBI loader
-such as Etherboot, use `nbgrub'. There is no difference between them
-except their formats. Since the way to load a second stage image you
-want to use should be described in the manual on your Net Boot ROM,
-please refer to the manual, for more information.
-
- However, there is one thing specific to GRUB. Namely, how to specify
-a configuration file in a BOOTP/DHCP server. For now, GRUB uses the tag
-`150', to get the name of a configuration file. The following is an
-example with a BOOTP configuration:
-
- .allhost:hd=/tmp:bf=null:\
- :ds=145.71.35.1 145.71.32.1:\
- :sm=255.255.254.0:\
- :gw=145.71.35.1:\
- :sa=145.71.35.5:
-
- foo:ht=1:ha=63655d0334a7:ip=145.71.35.127:\
- :bf=/nbgrub:\
- :tc=.allhost:\
- :T150="(nd)/tftpboot/menu.lst.foo":
-
- Note that you should specify the drive name `(nd)' in the name of
-the configuration file. This is because you might change the root drive
-before downloading the configuration from the TFTP server when the
-preset menu feature is used (*note Preset Menu::).
-
- See the manual of your BOOTP/DHCP server for more information. The
-exact syntax should differ a little from the example.
-
-7 Using GRUB via a serial line
-******************************
-
-This chapter describes how to use the serial terminal support in GRUB.
-
- If you have many computers or computers with no display/keyboard, it
-could be very useful to control the computers through serial
-communications. To connect one computer with another via a serial line,
-you need to prepare a null-modem (cross) serial cable, and you may need
-to have multiport serial boards, if your computer doesn't have extra
-serial ports. In addition, a terminal emulator is also required, such as
-minicom. Refer to a manual of your operating system, for more
-information.
-
- As for GRUB, the instruction to set up a serial terminal is quite
-simple. First of all, make sure that you haven't specified the option
-`--disable-serial' to the configure script when you built your GRUB
-images. If you get them in binary form, probably they have serial
-terminal support already.
-
- Then, initialize your serial terminal after GRUB starts up. Here is
-an example:
-
- grub> serial --unit=0 --speed=9600
- grub> terminal serial
-
- The command `serial' initializes the serial unit 0 with the speed
-9600bps. The serial unit 0 is usually called `COM1', so, if you want to
-use COM2, you must specify `--unit=1' instead. This command accepts
-many other options, so please refer to *Note serial::, for more details.
-
- The command `terminal' (*note terminal::) chooses which type of
-terminal you want to use. In the case above, the terminal will be a
-serial terminal, but you can also pass `console' to the command, as
-`terminal serial console'. In this case, a terminal in which you press
-any key will be selected as a GRUB terminal.
-
- However, note that GRUB assumes that your terminal emulator is
-compatible with VT100 by default. This is true for most terminal
-emulators nowadays, but you should pass the option `--dumb' to the
-command if your terminal emulator is not VT100-compatible or implements
-few VT100 escape sequences. If you specify this option then GRUB
-provides you with an alternative menu interface, because the normal
-menu requires several fancy features of your terminal.
-
-8 Embedding a configuration file into GRUB
-******************************************
-
-GRUB supports a "preset menu" which is to be always loaded before
-starting. The preset menu feature is useful, for example, when your
-computer has no console but a serial cable. In this case, it is
-critical to set up the serial terminal as soon as possible, since you
-cannot see any message until the serial terminal begins to work. So it
-is good to run the commands `serial' (*note serial::) and `terminal'
-(*note terminal::) before anything else at the start-up time.
-
- How the preset menu works is slightly complicated:
-
- 1. GRUB checks if the preset menu feature is used, and loads the
- preset menu, if available. This includes running commands and
- reading boot entries, like an ordinary configuration file.
-
- 2. GRUB checks if the configuration file is available. Note that this
- check is performed *regardless of the existence of the preset
- menu*. The configuration file is loaded even if the preset menu was
- loaded.
-
- 3. If the preset menu includes any boot entries, they are cleared when
- the configuration file is loaded. It doesn't matter whether the
- configuration file has any entries or no entry. The boot entries
- in the preset menu are used only when GRUB fails in loading the
- configuration file.
-
- To enable the preset menu feature, you must rebuild GRUB specifying a
-file to the configure script with the option `--enable-preset-menu'.
-The file has the same semantics as normal configuration files (*note
-Configuration::).
-
- Another point you should take care is that the diskless support
-(*note Diskless::) diverts the preset menu. Diskless images embed a
-preset menu to execute the command `bootp' (*note bootp::)
-automatically, unless you specify your own preset menu to the configure
-script. This means that you must put commands to initialize a network in
-the preset menu yourself, because diskless images don't set it up
-implicitly, when you use the preset menu explicitly.
-
- Therefore, a typical preset menu used with diskless support would be
-like this:
-
- # Set up the serial terminal, first of all.
- serial --unit=0 --speed=19200
- terminal --timeout=0 serial
-
- # Initialize the network.
- dhcp
-
-9 Protecting your computer from cracking
-****************************************
-
-You may be interested in how to prevent ordinary users from doing
-whatever they like, if you share your computer with other people. So
-this chapter describes how to improve the security of GRUB.
-
- One thing which could be a security hole is that the user can do too
-many things with GRUB, because GRUB allows one to modify its
-configuration and run arbitrary commands at run-time. For example, the
-user can even read `/etc/passwd' in the command-line interface by the
-command `cat' (*note cat::). So it is necessary to disable all the
-interactive operations.
-
- Thus, GRUB provides a "password" feature, so that only administrators
-can start the interactive operations (i.e. editing menu entries and
-entering the command-line interface). To use this feature, you need to
-run the command `password' in your configuration file (*note
-password::), like this:
-
- password --md5 PASSWORD
-
- If this is specified, GRUB disallows any interactive control, until
-you press the key <p> and enter a correct password. The option `--md5'
-tells GRUB that `PASSWORD' is in MD5 format. If it is omitted, GRUB
-assumes the `PASSWORD' is in clear text.
-
- You can encrypt your password with the command `md5crypt' (*note
-md5crypt::). For example, run the grub shell (*note Invoking the grub
-shell::), and enter your password:
-
- grub> md5crypt
- Password: **********
- Encrypted: $1$U$JK7xFegdxWH6VuppCUSIb.
-
- Then, cut and paste the encrypted password to your configuration
-file.
-
- Also, you can specify an optional argument to `password'. See this
-example:
-
- password PASSWORD /boot/grub/menu-admin.lst
-
- In this case, GRUB will load `/boot/grub/menu-admin.lst' as a
-configuration file when you enter the valid password.
-
- Another thing which may be dangerous is that any user can choose any
-menu entry. Usually, this wouldn't be problematic, but you might want to
-permit only administrators to run some of your menu entries, such as an
-entry for booting an insecure OS like DOS.
-
- GRUB provides the command `lock' (*note lock::). This command always
-fails until you enter the valid password, so you can use it, like this:
-
- title Boot DOS
- lock
- rootnoverify (hd0,1)
- makeactive
- chainload +1
-
- You should insert `lock' right after `title', because any user can
-execute commands in an entry until GRUB encounters `lock'.
-
- You can also use the command `password' instead of `lock'. In this
-case the boot process will ask for the password and stop if it was
-entered incorrectly. Since the `password' takes its own PASSWORD
-argument this is useful if you want different passwords for different
-entries.
-
-10 GRUB image files
-*******************
-
-GRUB consists of several images: two essential stages, optional stages
-called "Stage 1.5", one image for bootable CD-ROM, and two network boot
-images. Here is a short overview of them. *Note Internals::, for more
-details.
-
-`stage1'
- This is an essential image used for booting up GRUB. Usually, this
- is embedded in an MBR or the boot sector of a partition. Because a
- PC boot sector is 512 bytes, the size of this image is exactly 512
- bytes.
-
- All `stage1' must do is to load Stage 2 or Stage 1.5 from a local
- disk. Because of the size restriction, `stage1' encodes the
- location of Stage 2 (or Stage 1.5) in a block list format, so it
- never understand any filesystem structure.
-
-`stage2'
- This is the core image of GRUB. It does everything but booting up
- itself. Usually, this is put in a filesystem, but that is not
- required.
-
-`e2fs_stage1_5'
-`fat_stage1_5'
-`ffs_stage1_5'
-`jfs_stage1_5'
-`minix_stage1_5'
-`reiserfs_stage1_5'
-`vstafs_stage1_5'
-`xfs_stage1_5'
- These are called "Stage 1.5", because they serve as a bridge
- between `stage1' and `stage2', that is to say, Stage 1.5 is loaded
- by Stage 1 and Stage 1.5 loads Stage 2. The difference between
- `stage1' and `*_stage1_5' is that the former doesn't understand
- any filesystem while the latter understands one filesystem (e.g.
- `e2fs_stage1_5' understands ext2fs). So you can move the Stage 2
- image to another location safely, even after GRUB has been
- installed.
-
- While Stage 2 cannot generally be embedded in a fixed area as the
- size is so large, Stage 1.5 can be installed into the area right
- after an MBR, or the boot loader area of a ReiserFS or a FFS.
-
-`stage2_eltorito'
- This is a boot image for CD-ROMs using the "no emulation mode" in
- El Torito specification. This is identical to Stage 2, except that
- this boots up without Stage 1 and sets up a special drive `(cd)'.
-
-`nbgrub'
- This is a network boot image for the Network Image Proposal used
- by some network boot loaders, such as Etherboot. This is mostly
- the same as Stage 2, but it also sets up a network and loads a
- configuration file from the network.
-
-`pxegrub'
- This is another network boot image for the Preboot Execution
- Environment used by several Netboot ROMs. This is identical to
- `nbgrub', except for the format.
-
-11 Filesystem syntax and semantics
-**********************************
-
-GRUB uses a special syntax for specifying disk drives which can be
-accessed by BIOS. Because of BIOS limitations, GRUB cannot distinguish
-between IDE, ESDI, SCSI, or others. You must know yourself which BIOS
-device is equivalent to which OS device. Normally, that will be clear if
-you see the files in a device or use the command `find' (*note find::).
-
-11.1 How to specify devices
-===========================
-
-The device syntax is like this:
-
- `(DEVICE[,PART-NUM][,BSD-SUBPART-LETTER])'
-
- `[]' means the parameter is optional. DEVICE should be either `fd'
-or `hd' followed by a digit, like `fd0'. But you can also set DEVICE
-to a hexadecimal or a decimal number which is a BIOS drive number, so
-the following are equivalent:
-
- (hd0)
- (0x80)
- (128)
-
- PART-NUM represents the partition number of DEVICE, starting from
-zero for primary partitions and from four for extended partitions, and
-BSD-SUBPART-LETTER represents the BSD disklabel subpartition, such as
-`a' or `e'.
-
- A shortcut for specifying BSD subpartitions is
-`(DEVICE,BSD-SUBPART-LETTER)', in this case, GRUB searches for the
-first PC partition containing a BSD disklabel, then finds the
-subpartition BSD-SUBPART-LETTER. Here is an example:
-
- (hd0,a)
-
- The syntax `(hd0)' represents using the entire disk (or the MBR when
-installing GRUB), while the syntax `(hd0,0)' represents using the first
-partition of the disk (or the boot sector of the partition when
-installing GRUB).
-
- If you enabled the network support, the special drive, `(nd)', is
-also available. Before using the network drive, you must initialize the
-network. *Note Network::, for more information.
-
- If you boot GRUB from a CD-ROM, `(cd)' is available. *Note Making a
-GRUB bootable CD-ROM::, for details.
-
-11.2 How to specify files
-=========================
-
-There are two ways to specify files, by "absolute file name" and by
-"block list".
-
- An absolute file name resembles a Unix absolute file name, using `/'
-for the directory separator (not `\' as in DOS). One example is
-`(hd0,0)/boot/grub/menu.lst'. This means the file `/boot/grub/menu.lst'
-in the first partition of the first hard disk. If you omit the device
-name in an absolute file name, GRUB uses GRUB's "root device"
-implicitly. So if you set the root device to, say, `(hd1,0)' by the
-command `root' (*note root::), then `/boot/kernel' is the same as
-`(hd1,0)/boot/kernel'.
-
-11.3 How to specify block lists
-===============================
-
-A block list is used for specifying a file that doesn't appear in the
-filesystem, like a chainloader. The syntax is
-`[OFFSET]+LENGTH[,[OFFSET]+LENGTH]...'. Here is an example:
-
- `0+100,200+1,300+300'
-
- This represents that GRUB should read blocks 0 through 99, block 200,
-and blocks 300 through 599. If you omit an offset, then GRUB assumes
-the offset is zero.
-
- Like the file name syntax (*note File name syntax::), if a blocklist
-does not contain a device name, then GRUB uses GRUB's "root device". So
-`(hd0,1)+1' is the same as `+1' when the root device is `(hd0,1)'.
-
-12 GRUB's user interface
-************************
-
-GRUB has both a simple menu interface for choosing preset entries from a
-configuration file, and a highly flexible command-line for performing
-any desired combination of boot commands.
-
- GRUB looks for its configuration file as soon as it is loaded. If one
-is found, then the full menu interface is activated using whatever
-entries were found in the file. If you choose the "command-line" menu
-option, or if the configuration file was not found, then GRUB drops to
-the command-line interface.
-
-12.1 The flexible command-line interface
-========================================
-
-The command-line interface provides a prompt and after it an editable
-text area much like a command-line in Unix or DOS. Each command is
-immediately executed after it is entered(1) (*note Command-line
-interface-Footnote-1::). The commands (*note Command-line and menu
-entry commands::) are a subset of those available in the configuration
-file, used with exactly the same syntax.
-
- Cursor movement and editing of the text on the line can be done via a
-subset of the functions available in the Bash shell:
-
-<C-f>
-<PC right key>
- Move forward one character.
-
-<C-b>
-<PC left key>
- Move back one character.
-
-<C-a>
-<HOME>
- Move to the start of the line.
-
-<C-e>
-<END>
- Move the the end of the line.
-
-<C-d>
-<DEL>
- Delete the character underneath the cursor.
-
-<C-h>
-<BS>
- Delete the character to the left of the cursor.
-
-<C-k>
- Kill the text from the current cursor position to the end of the
- line.
-
-<C-u>
- Kill backward from the cursor to the beginning of the line.
-
-<C-y>
- Yank the killed text back into the buffer at the cursor.
-
-<C-p>
-<PC up key>
- Move up through the history list.
-
-<C-n>
-<PC down key>
- Move down through the history list.
-
- When typing commands interactively, if the cursor is within or before
-the first word in the command-line, pressing the <TAB> key (or <C-i>)
-will display a listing of the available commands, and if the cursor is
-after the first word, the `<TAB>' will provide a completion listing of
-disks, partitions, and file names depending on the context. Note that
-to obtain a list of drives, one must open a parenthesis, as `root ('.
-
- Note that you cannot use the completion functionality in the TFTP
-filesystem. This is because TFTP doesn't support file name listing for
-the security.
-
- (1) However, this behavior will be changed in the future version, in
-a user-invisible way.
-
-12.2 The simple menu interface
-==============================
-
-The menu interface is quite easy to use. Its commands are both
-reasonably intuitive and described on screen.
-
- Basically, the menu interface provides a list of "boot entries" to
-the user to choose from. Use the arrow keys to select the entry of
-choice, then press <RET> to run it. An optional timeout is available
-to boot the default entry (the first one if not set), which is aborted
-by pressing any key.
-
- Commands are available to enter a bare command-line by pressing <c>
-(which operates exactly like the non-config-file version of GRUB, but
-allows one to return to the menu if desired by pressing <ESC>) or to
-edit any of the "boot entries" by pressing <e>.
-
- If you protect the menu interface with a password (*note Security::),
-all you can do is choose an entry by pressing <RET>, or press <p> to
-enter the password.
-
-12.3 Editing a menu entry
-=========================
-
-The menu entry editor looks much like the main menu interface, but the
-lines in the menu are individual commands in the selected entry instead
-of entry names.
-
- If an <ESC> is pressed in the editor, it aborts all the changes made
-to the configuration entry and returns to the main menu interface.
-
- When a particular line is selected, the editor places the user in a
-special version of the GRUB command-line to edit that line. When the
-user hits <RET>, GRUB replaces the line in question in the boot entry
-with the changes (unless it was aborted via <ESC>, in which case the
-changes are thrown away).
-
- If you want to add a new line to the menu entry, press <o> if adding
-a line after the current line or press <O> if before the current line.
-
- To delete a line, hit the key <d>. Although GRUB unfortunately does
-not support "undo", you can do almost the same thing by just returning
-to the main menu.
-
-12.4 The hidden menu interface
-==============================
-
-When your terminal is dumb or you request GRUB to hide the menu
-interface explicitly with the command `hiddenmenu' (*note
-hiddenmenu::), GRUB doesn't show the menu interface (*note Menu
-interface::) and automatically boots the default entry, unless
-interrupted by pressing <ESC>.
-
- When you interrupt the timeout and your terminal is dumb, GRUB falls
-back to the command-line interface (*note Command-line interface::).
-
-13 The list of available commands
-*********************************
-
-In this chapter, we list all commands that are available in GRUB.
-
- Commands belong to different groups. A few can only be used in the
-global section of the configuration file (or "menu"); most of them can
-be entered on the command-line and can be used either anywhere in the
-menu or specifically in the menu entries.
-
-13.1 The list of commands for the menu only
-===========================================
-
-The semantics used in parsing the configuration file are the following:
-
- * The menu-specific commands have to be used before any others.
-
- * The files _must_ be in plain-text format.
-
- * `#' at the beginning of a line in a configuration file means it is
- only a comment.
-
- * Options are separated by spaces.
-
- * All numbers can be either decimal or hexadecimal. A hexadecimal
- number must be preceded by `0x', and is case-insensitive.
-
- * Extra options or text at the end of the line are ignored unless
- otherwise specified.
-
- * Unrecognized commands are added to the current entry, except
- before entries start, where they are ignored.
-
- These commands can only be used in the menu:
-
-13.1.1 default
---------------
-
- -- Command: default num
- Set the default entry to the entry number NUM. Numbering starts
- from 0, and the entry number 0 is the default if the command is not
- used.
-
- You can specify `saved' instead of a number. In this case, the
- default entry is the entry saved with the command `savedefault'.
- *Note savedefault::, for more information.
-
-13.1.2 fallback
----------------
-
- -- Command: fallback num...
- Go into unattended boot mode: if the default boot entry has any
- errors, instead of waiting for the user to do something,
- immediately start over using the NUM entry (same numbering as the
- `default' command (*note default::)). This obviously won't help if
- the machine was rebooted by a kernel that GRUB loaded. You can
- specify multiple fallback entry numbers.
-
-13.1.3 hiddenmenu
------------------
-
- -- Command: hiddenmenu
- Don't display the menu. If the command is used, no menu will be
- displayed on the control terminal, and the default entry will be
- booted after the timeout expired. The user can still request the
- menu to be displayed by pressing <ESC> before the timeout expires.
- See also *Note Hidden menu interface::.
-
-13.1.4 timeout
---------------
-
- -- Command: timeout sec
- Set a timeout, in SEC seconds, before automatically booting the
- default entry (normally the first entry defined).
-
-13.1.5 title
-------------
-
- -- Command: title name ...
- Start a new boot entry, and set its name to the contents of the
- rest of the line, starting with the first non-space character.
-
-13.2 The list of general commands
-=================================
-
-Commands usable anywhere in the menu and in the command-line.
-
-13.2.1 bootp
-------------
-
- -- Command: bootp [`--with-configfile']
- Initialize a network device via the "BOOTP" protocol. This command
- is only available if GRUB is compiled with netboot support. See
- also *Note Network::.
-
- If you specify `--with-configfile' to this command, GRUB will
- fetch and load a configuration file specified by your BOOTP server
- with the vendor tag `150'.
-
-13.2.2 color
-------------
-
- -- Command: color normal [highlight]
- Change the menu colors. The color NORMAL is used for most lines in
- the menu (*note Menu interface::), and the color HIGHLIGHT is used
- to highlight the line where the cursor points. If you omit
- HIGHLIGHT, then the inverted color of NORMAL is used for the
- highlighted line. The format of a color is
- `FOREGROUND/BACKGROUND'. FOREGROUND and BACKGROUND are symbolic
- color names. A symbolic color name must be one of these:
-
- * black
-
- * blue
-
- * green
-
- * cyan
-
- * red
-
- * magenta
-
- * brown
-
- * light-gray
-
- *These below can be specified only for the foreground.*
-
- * dark-gray
-
- * light-blue
-
- * light-green
-
- * light-cyan
-
- * light-red
-
- * light-magenta
-
- * yellow
-
- * white
-
- But only the first eight names can be used for BACKGROUND. You can
- prefix `blink-' to FOREGROUND if you want a blinking foreground
- color.
-
- This command can be used in the configuration file and on the
- command line, so you may write something like this in your
- configuration file:
-
- # Set default colors.
- color light-gray/blue black/light-gray
-
- # Change the colors.
- title OS-BS like
- color magenta/blue black/magenta
-
-13.2.3 device
--------------
-
- -- Command: device drive file
- In the grub shell, specify the file FILE as the actual drive for a
- BIOS drive DRIVE. You can use this command to create a disk image,
- and/or to fix the drives guessed by GRUB when GRUB fails to
- determine them correctly, like this:
-
- grub> device (fd0) /floppy-image
- grub> device (hd0) /dev/sd0
-
- This command can be used only in the grub shell (*note Invoking
- the grub shell::).
-
-13.2.4 dhcp
------------
-
- -- Command: dhcp [-with-configfile]
- Initialize a network device via the "DHCP" protocol. Currently,
- this command is just an alias for `bootp', since the two protocols
- are very similar. This command is only available if GRUB is
- compiled with netboot support. See also *Note Network::.
-
- If you specify `--with-configfile' to this command, GRUB will
- fetch and load a configuration file specified by your DHCP server
- with the vendor tag `150'.
-
-13.2.5 hide
------------
-
- -- Command: hide partition
- Hide the partition PARTITION by setting the "hidden" bit in its
- partition type code. This is useful only when booting DOS or
- Windows and multiple primary FAT partitions exist in one disk. See
- also *Note DOS/Windows::.
-
-13.2.6 ifconfig
----------------
-
- -- Command: ifconfig [`--server=server'] [`--gateway=gateway']
- [`--mask=mask'] [`--address=address']
- Configure the IP address, the netmask, the gateway, and the server
- address of a network device manually. The values must be in dotted
- decimal format, like `192.168.11.178'. The order of the options is
- not important. This command shows current network configuration,
- if no option is specified. See also *Note Network::.
-
-13.2.7 pager
-------------
-
- -- Command: pager [flag]
- Toggle or set the state of the internal pager. If FLAG is `on',
- the internal pager is enabled. If FLAG is `off', it is disabled.
- If no argument is given, the state is toggled.
-
-13.2.8 partnew
---------------
-
- -- Command: partnew part type from len
- Create a new primary partition. PART is a partition specification
- in GRUB syntax (*note Naming convention::); TYPE is the partition
- type and must be a number in the range `0-0xff'; FROM is the
- starting address and LEN is the length, both in sector units.
-
-13.2.9 parttype
----------------
-
- -- Command: parttype part type
- Change the type of an existing partition. PART is a partition
- specification in GRUB syntax (*note Naming convention::); TYPE is
- the new partition type and must be a number in the range 0-0xff.
-
-13.2.10 password
-----------------
-
- -- Command: password [`--md5'] passwd [new-config-file]
- If used in the first section of a menu file, disable all
- interactive editing control (menu entry editor and command-line)
- and entries protected by the command `lock'. If the password
- PASSWD is entered, it loads the NEW-CONFIG-FILE as a new config
- file and restarts the GRUB Stage 2, if NEW-CONFIG-FILE is
- specified. Otherwise, GRUB will just unlock the privileged
- instructions. You can also use this command in the script
- section, in which case it will ask for the password, before
- continuing. The option `--md5' tells GRUB that PASSWD is
- encrypted with `md5crypt' (*note md5crypt::).
-
-13.2.11 rarp
-------------
-
- -- Command: rarp
- Initialize a network device via the "RARP" protocol. This command
- is only available if GRUB is compiled with netboot support. See
- also *Note Network::.
-
-13.2.12 serial
---------------
-
- -- Command: serial [`--unit=unit'] [`--port=port'] [`--speed=speed']
- [`--word=word'] [`--parity=parity'] [`--stop=stop']
- [`--device=dev']
- Initialize a serial device. UNIT is a number in the range 0-3
- specifying which serial port to use; default is 0, which
- corresponds to the port often called COM1. PORT is the I/O port
- where the UART is to be found; if specified it takes precedence
- over UNIT. SPEED is the transmission speed; default is 9600. WORD
- and STOP are the number of data bits and stop bits. Data bits must
- be in the range 5-8 and stop bits must be 1 or 2. Default is 8 data
- bits and one stop bit. PARITY is one of `no', `odd', `even' and
- defaults to `no'. The option `--device' can only be used in the
- grub shell and is used to specify the tty device to be used in the
- host operating system (*note Invoking the grub shell::).
-
- The serial port is not used as a communication channel unless the
- `terminal' command is used (*note terminal::).
-
- This command is only available if GRUB is compiled with serial
- support. See also *Note Serial terminal::.
-
-13.2.13 setkey
---------------
-
- -- Command: setkey [to_key from_key]
- Change the keyboard map. The key FROM_KEY is mapped to the key
- TO_KEY. If no argument is specified, reset key mappings. Note that
- this command _does not_ exchange the keys. If you want to exchange
- the keys, run this command again with the arguments exchanged,
- like this:
-
- grub> setkey capslock control
- grub> setkey control capslock
-
- A key must be an alphabet letter, a digit, or one of these symbols:
- `escape', `exclam', `at', `numbersign', `dollar', `percent',
- `caret', `ampersand', `asterisk', `parenleft', `parenright',
- `minus', `underscore', `equal', `plus', `backspace', `tab',
- `bracketleft', `braceleft', `bracketright', `braceright', `enter',
- `control', `semicolon', `colon', `quote', `doublequote',
- `backquote', `tilde', `shift', `backslash', `bar', `comma',
- `less', `period', `greater', `slash', `question', `alt', `space',
- `capslock', `FX' (`X' is a digit), and `delete'. This table
- describes to which character each of the symbols corresponds:
-
- `exclam'
- `!'
-
- `at'
- `@'
-
- `numbersign'
- `#'
-
- `dollar'
- `$'
-
- `percent'
- `%'
-
- `caret'
- `^'
-
- `ampersand'
- `&'
-
- `asterisk'
- `*'
-
- `parenleft'
- `('
-
- `parenright'
- `)'
-
- `minus'
- `-'
-
- `underscore'
- `_'
-
- `equal'
- `='
-
- `plus'
- `+'
-
- `bracketleft'
- `['
-
- `braceleft'
- `{'
-
- `bracketright'
- `]'
-
- `braceright'
- `}'
-
- `semicolon'
- `;'
-
- `colon'
- `:'
-
- `quote'
- `''
-
- `doublequote'
- `"'
-
- `backquote'
- ``'
-
- `tilde'
- `~'
-
- `backslash'
- `\'
-
- `bar'
- `|'
-
- `comma'
- `,'
-
- `less'
- `<'
-
- `period'
- `.'
-
- `greater'
- `>'
-
- `slash'
- `/'
-
- `question'
- `?'
-
- `space'
- ` '
-
-13.2.14 terminal
-----------------
-
- -- Command: terminal [`--dumb'] [`--no-echo'] [`--no-edit']
- [`--timeout=secs'] [`--lines=lines'] [`--silent'] [`console']
- [`serial'] [`hercules']
- Select a terminal for user interaction. The terminal is assumed to
- be VT100-compatible unless `--dumb' is specified. If both
- `console' and `serial' are specified, then GRUB will use the one
- where a key is entered first or the first when the timeout
- expires. If neither are specified, the current setting is
- reported. This command is only available if GRUB is compiled with
- serial support. See also *Note Serial terminal::.
-
- This may not make sense for most users, but GRUB supports Hercules
- console as well. Hercules console is usable like the ordinary
- console, and the usage is quite similar to that for serial
- terminals: specify `hercules' as the argument.
-
- The option `--lines' defines the number of lines in your terminal,
- and it is used for the internal pager function. If you don't
- specify this option, the number is assumed as 24.
-
- The option `--silent' suppresses the message to prompt you to hit
- any key. This might be useful if your system has no terminal
- device.
-
- The option `--no-echo' has GRUB not to echo back input characters.
- This implies the option `--no-edit'.
-
- The option `--no-edit' disables the BASH-like editing feature.
-
-13.2.15 terminfo
-----------------
-
- -- Command: terminfo `--name=name' `--cursor-address=seq'
- [`--clear-screen=seq'] [`--enter-standout-mode=seq']
- [`--exit-standout-mode=seq']
- Define the capabilities of your terminal. Use this command to
- define escape sequences, if it is not vt100-compatible. You may
- use `\e' for <ESC> and `^X' for a control character.
-
- You can use the utility `grub-terminfo' to generate appropriate
- arguments to this command. *Note Invoking grub-terminfo::.
-
- If no option is specified, the current settings are printed.
-
-13.2.16 tftpserver
-------------------
-
- -- Command: tftpserver ipaddr
- *Caution:* This command exists only for backward compatibility.
- Use `ifconfig' (*note ifconfig::) instead.
-
- Override a TFTP server address returned by a BOOTP/DHCP/RARP
- server. The argument IPADDR must be in dotted decimal format, like
- `192.168.0.15'. This command is only available if GRUB is compiled
- with netboot support. See also *Note Network::.
-
-13.2.17 unhide
---------------
-
- -- Command: unhide partition
- Unhide the partition PARTITION by clearing the "hidden" bit in its
- partition type code. This is useful only when booting DOS or
- Windows and multiple primary partitions exist on one disk. See also
- *Note DOS/Windows::.
-
-13.3 The list of command-line and menu entry commands
-=====================================================
-
-These commands are usable in the command-line and in menu entries. If
-you forget a command, you can run the command `help' (*note help::).
-
-13.3.1 blocklist
-----------------
-
- -- Command: blocklist file
- Print the block list notation of the file FILE. *Note Block list
- syntax::.
-
-13.3.2 boot
------------
-
- -- Command: boot
- Boot the OS or chain-loader which has been loaded. Only necessary
- if running the fully interactive command-line (it is implicit at
- the end of a menu entry).
-
-13.3.3 cat
-----------
-
- -- Command: cat file
- Display the contents of the file FILE. This command may be useful
- to remind you of your OS's root partition:
-
- grub> cat /etc/fstab
-
-13.3.4 chainloader
-------------------
-
- -- Command: chainloader [`--force'] file
- Load FILE as a chain-loader. Like any other file loaded by the
- filesystem code, it can use the blocklist notation to grab the
- first sector of the current partition with `+1'. If you specify the
- option `--force', then load FILE forcibly, whether it has a
- correct signature or not. This is required when you want to load a
- defective boot loader, such as SCO UnixWare 7.1 (*note SCO
- UnixWare::).
-
-13.3.5 cmp
-----------
-
- -- Command: cmp file1 file2
- Compare the file FILE1 with the file FILE2. If they differ in
- size, print the sizes like this:
-
- Differ in size: 0x1234 [foo], 0x4321 [bar]
-
- If the sizes are equal but the bytes at an offset differ, then
- print the bytes like this:
-
- Differ at the offset 777: 0xbe [foo], 0xef [bar]
-
- If they are completely identical, nothing will be printed.
-
-13.3.6 configfile
------------------
-
- -- Command: configfile file
- Load FILE as a configuration file.
-
-13.3.7 debug
-------------
-
- -- Command: debug
- Toggle debug mode (by default it is off). When debug mode is on,
- some extra messages are printed to show disk activity. This global
- debug flag is mainly useful for GRUB developers when testing new
- code.
-
-13.3.8 displayapm
------------------
-
- -- Command: displayapm
- Display APM BIOS information.
-
-13.3.9 displaymem
------------------
-
- -- Command: displaymem
- Display what GRUB thinks the system address space map of the
- machine is, including all regions of physical RAM installed. GRUB's
- "upper/lower memory" display uses the standard BIOS interface for
- the available memory in the first megabyte, or "lower memory", and
- a synthesized number from various BIOS interfaces of the memory
- starting at 1MB and going up to the first chipset hole for "upper
- memory" (the standard PC "upper memory" interface is limited to
- reporting a maximum of 64MB).
-
-13.3.10 embed
--------------
-
- -- Command: embed stage1_5 device
- Embed the Stage 1.5 STAGE1_5 in the sectors after the MBR if
- DEVICE is a drive, or in the "boot loader" area if DEVICE is a FFS
- partition or a ReiserFS partition.(1) (*note embed-Footnote-1::)
- Print the number of sectors which STAGE1_5 occupies, if successful.
-
- Usually, you don't need to run this command directly. *Note
- setup::.
-
- (1) The latter feature has not been implemented yet.
-
-13.3.11 find
-------------
-
- -- Command: find filename
- Search for the file name FILENAME in all mountable partitions and
- print the list of the devices which contain the file. The file
- name FILENAME should be an absolute file name like
- `/boot/grub/stage1'.
-
-13.3.12 fstest
---------------
-
- -- Command: fstest
- Toggle filesystem test mode. Filesystem test mode, when turned
- on, prints out data corresponding to all the device reads and what
- values are being sent to the low-level routines. The format is
- `<PARTITION-OFFSET-SECTOR, BYTE-OFFSET, BYTE-LENGTH>' for
- high-level reads inside a partition, and `[DISK-OFFSET-SECTOR]'
- for low-level sector requests from the disk. Filesystem test mode
- is turned off by any use of the `install' (*note install::) or
- `testload' (*note testload::) commands.
-
-13.3.13 geometry
-----------------
-
- -- Command: geometry drive [cylinder head sector [total_sector]]
- Print the information for the drive DRIVE. In the grub shell, you
- can set the geometry of the drive arbitrarily. The number of
- cylinders, the number of heads, the number of sectors and the
- number of total sectors are set to CYLINDER, HEAD, SECTOR and
- TOTAL_SECTOR, respectively. If you omit TOTAL_SECTOR, then it will
- be calculated based on the C/H/S values automatically.
-
-13.3.14 halt
-------------
-
- -- Command: halt `--no-apm'
- The command halts the computer. If the `--no-apm' option is
- specified, no APM BIOS call is performed. Otherwise, the computer
- is shut down using APM.
-
-13.3.15 help
-------------
-
- -- Command: help `--all' [pattern ...]
- Display helpful information about builtin commands. If you do not
- specify PATTERN, this command shows short descriptions of most of
- available commands. If you specify the option `--all' to this
- command, short descriptions of rarely used commands (such as *Note
- testload::) are displayed as well.
-
- If you specify any PATTERNS, it displays longer information about
- each of the commands which match those PATTERNS.
-
-13.3.16 impsprobe
------------------
-
- -- Command: impsprobe
- Probe the Intel Multiprocessor Specification 1.1 or 1.4
- configuration table and boot the various CPUs which are found into
- a tight loop. This command can be used only in the Stage 2, but
- not in the grub shell.
-
-13.3.17 initrd
---------------
-
- -- Command: initrd file ...
- Load an initial ramdisk for a Linux format boot image and set the
- appropriate parameters in the Linux setup area in memory. See also
- *Note GNU/Linux::.
-
-13.3.18 install
----------------
-
- -- Command: install [`--force-lba'] [`--stage2=os_stage2_file']
- stage1_file [`d'] dest_dev stage2_file [addr] [`p']
- [config_file] [real_config_file]
- This command is fairly complex, and you should not use this command
- unless you are familiar with GRUB. Use `setup' (*note setup::)
- instead.
-
- In short, it will perform a full install presuming the Stage 2 or
- Stage 1.5(1) (*note install-Footnote-1::) is in its final install
- location.
-
- In slightly more detail, it will load STAGE1_FILE, validate that
- it is a GRUB Stage 1 of the right version number, install in it a
- blocklist for loading STAGE2_FILE as a Stage 2. If the option `d'
- is present, the Stage 1 will always look for the actual disk
- STAGE2_FILE was installed on, rather than using the booting drive.
- The Stage 2 will be loaded at address ADDR, which must be `0x8000'
- for a true Stage 2, and `0x2000' for a Stage 1.5. If ADDR is not
- present, GRUB will determine the address automatically. It then
- writes the completed Stage 1 to the first block of the device
- DEST_DEV. If the options `p' or CONFIG_FILE are present, then it
- reads the first block of stage2, modifies it with the values of
- the partition STAGE2_FILE was found on (for `p') or places the
- string CONFIG_FILE into the area telling the stage2 where to look
- for a configuration file at boot time. Likewise, if
- REAL_CONFIG_FILE is present and STAGE2_FILE is a Stage 1.5, then
- the Stage 2 CONFIG_FILE is patched with the configuration file
- name REAL_CONFIG_FILE. This command preserves the DOS BPB (and for
- hard disks, the partition table) of the sector the Stage 1 is to
- be installed into.
-
- *Caution:* Several buggy BIOSes don't pass a booting drive
- properly when booting from a hard disk drive. Therefore, you will
- unfortunately have to specify the option `d', whether your Stage2
- resides at the booting drive or not, if you have such a BIOS. We
- know these are defective in this way:
-
-
- Fujitsu LifeBook 400 BIOS version 31J0103A
-
-
- HP Vectra XU 6/200 BIOS version GG.06.11
-
- *Caution2:* A number of BIOSes don't return a correct LBA support
- bitmap even if they do have the support. So GRUB provides a
- solution to ignore the wrong bitmap, that is, the option
- `--force-lba'. Don't use this option if you know that your BIOS
- doesn't have LBA support.
-
- *Caution3:* You must specify the option `--stage2' in the grub
- shell, if you cannot unmount the filesystem where your stage2 file
- resides. The argument should be the file name in your operating
- system.
-
- (1) They're loaded the same way, so we will refer to the Stage 1.5
-as a Stage 2 from now on.
-
-13.3.19 ioprobe
----------------
-
- -- Command: ioprobe drive
- Probe I/O ports used for the drive DRIVE. This command will list
- the I/O ports on the screen. For technical information, *Note
- Internals::.
-
-13.3.20 kernel
---------------
-
- -- Command: kernel [`--type=type'] [`--no-mem-option'] file ...
- Attempt to load the primary boot image (Multiboot a.out or ELF,
- Linux zImage or bzImage, FreeBSD a.out, NetBSD a.out, etc.) from
- FILE. The rest of the line is passed verbatim as the "kernel
- command-line". Any modules must be reloaded after using this
- command.
-
- This command also accepts the option `--type' so that you can
- specify the kernel type of FILE explicitly. The argument TYPE must
- be one of these: `netbsd', `freebsd', `openbsd', `linux',
- `biglinux', and `multiboot'. However, you need to specify it only
- if you want to load a NetBSD ELF kernel, because GRUB can
- automatically determine a kernel type in the other cases, quite
- safely.
-
- The option `--no-mem-option' is effective only for Linux. If the
- option is specified, GRUB doesn't pass the option `mem=' to the
- kernel. This option is implied for Linux kernels 2.4.18 and newer.
-
-13.3.21 lock
-------------
-
- -- Command: lock
- Prevent normal users from executing arbitrary menu entries. You
- must use the command `password' if you really want this command to
- be useful (*note password::).
-
- This command is used in a menu, as shown in this example:
-
- title This entry is too dangerous to be executed by normal users
- lock
- root (hd0,a)
- kernel /no-security-os
-
- See also *Note Security::.
-
-13.3.22 makeactive
-------------------
-
- -- Command: makeactive
- Set the active partition on the root disk to GRUB's root device.
- This command is limited to _primary_ PC partitions on a hard disk.
-
-13.3.23 map
------------
-
- -- Command: map to_drive from_drive
- Map the drive FROM_DRIVE to the drive TO_DRIVE. This is necessary
- when you chain-load some operating systems, such as DOS, if such
- an OS resides at a non-first drive. Here is an example:
-
- grub> map (hd0) (hd1)
- grub> map (hd1) (hd0)
-
- The example exchanges the order between the first hard disk and the
- second hard disk. See also *Note DOS/Windows::.
-
-13.3.24 md5crypt
-----------------
-
- -- Command: md5crypt
- Prompt to enter a password, and encrypt it in MD5 format. The
- encrypted password can be used with the command `password' (*note
- password::). See also *Note Security::.
-
-13.3.25 module
---------------
-
- -- Command: module file ...
- Load a boot module FILE for a Multiboot format boot image (no
- interpretation of the file contents are made, so the user of this
- command must know what the kernel in question expects). The rest
- of the line is passed as the "module command-line", like the
- `kernel' command. You must load a Multiboot kernel image before
- loading any module. See also *Note modulenounzip::.
-
-13.3.26 modulenounzip
----------------------
-
- -- Command: modulenounzip file ...
- The same as `module' (*note module::), except that automatic
- decompression is disabled.
-
-13.3.27 pause
--------------
-
- -- Command: pause message ...
- Print the MESSAGE, then wait until a key is pressed. Note that
- placing <^G> (ASCII code 7) in the message will cause the speaker
- to emit the standard beep sound, which is useful when prompting
- the user to change floppies.
-
-13.3.28 quit
-------------
-
- -- Command: quit
- Exit from the grub shell `grub' (*note Invoking the grub shell::).
- This command can be used only in the grub shell.
-
-13.3.29 reboot
---------------
-
- -- Command: reboot
- Reboot the computer.
-
-13.3.30 read
-------------
-
- -- Command: read addr
- Read a 32-bit value from memory at address ADDR and display it in
- hex format.
-
-13.3.31 root
-------------
-
- -- Command: root device [hdbias]
- Set the current "root device" to the device DEVICE, then attempt
- to mount it to get the partition size (for passing the partition
- descriptor in `ES:ESI', used by some chain-loaded boot loaders),
- the BSD drive-type (for booting BSD kernels using their native
- boot format), and correctly determine the PC partition where a BSD
- sub-partition is located. The optional HDBIAS parameter is a
- number to tell a BSD kernel how many BIOS drive numbers are on
- controllers before the current one. For example, if there is an
- IDE disk and a SCSI disk, and your FreeBSD root partition is on
- the SCSI disk, then use a `1' for HDBIAS.
-
- See also *Note rootnoverify::.
-
-13.3.32 rootnoverify
---------------------
-
- -- Command: rootnoverify device [hdbias]
- Similar to `root' (*note root::), but don't attempt to mount the
- partition. This is useful for when an OS is outside of the area of
- the disk that GRUB can read, but setting the correct root device
- is still desired. Note that the items mentioned in `root' above
- which derived from attempting the mount will _not_ work correctly.
-
-13.3.33 savedefault
--------------------
-
- -- Command: savedefault num
- Save the current menu entry or NUM if specified as a default
- entry. Here is an example:
-
- default saved
- timeout 10
-
- title GNU/Linux
- root (hd0,0)
- kernel /boot/vmlinuz root=/dev/sda1 vga=ext
- initrd /boot/initrd
- savedefault
-
- title FreeBSD
- root (hd0,a)
- kernel /boot/loader
- savedefault
-
- With this configuration, GRUB will choose the entry booted
- previously as the default entry.
-
- You can specify `fallback' instead of a number. Then, next
- fallback entry is saved. Next fallback entry is chosen from
- fallback entries. Normally, this will be the first entry in
- fallback ones.
-
- See also *Note default:: and *Note Invoking grub-set-default::.
-
-13.3.34 setup
--------------
-
- -- Command: setup [`--force-lba'] [`--stage2=os_stage2_file']
- [`--prefix=dir'] install_device [image_device]
- Set up the installation of GRUB automatically. This command uses
- the more flexible command `install' (*note install::) in the
- backend and installs GRUB into the device INSTALL_DEVICE. If
- IMAGE_DEVICE is specified, then find the GRUB images (*note
- Images::) in the device IMAGE_DEVICE, otherwise use the current
- "root device", which can be set by the command `root'. If
- INSTALL_DEVICE is a hard disk, then embed a Stage 1.5 in the disk
- if possible.
-
- The option `--prefix' specifies the directory under which GRUB
- images are put. If it is not specified, GRUB automatically
- searches them in `/boot/grub' and `/grub'.
-
- The options `--force-lba' and `--stage2' are just passed to
- `install' if specified. *Note install::, for more information.
-
-13.3.35 testload
-----------------
-
- -- Command: testload file
- Read the entire contents of FILE in several different ways and
- compare them, to test the filesystem code. The output is somewhat
- cryptic, but if no errors are reported and the final `i=X,
- filepos=Y' reading has X and Y equal, then it is definitely
- consistent, and very likely works correctly subject to a
- consistent offset error. If this test succeeds, then a good next
- step is to try loading a kernel.
-
-13.3.36 testvbe
----------------
-
- -- Command: testvbe mode
- Test the VESA BIOS EXTENSION mode MODE. This command will switch
- your video card to the graphics mode, and show an endless
- animation. Hit any key to return. See also *Note vbeprobe::.
-
-13.3.37 uppermem
-----------------
-
- -- Command: uppermem kbytes
- Force GRUB to assume that only KBYTES kilobytes of upper memory
- are installed. Any system address range maps are discarded.
-
- *Caution:* This should be used with great caution, and should only
- be necessary on some old machines. GRUB's BIOS probe can pick up
- all RAM on all new machines the author has ever heard of. It can
- also be used for debugging purposes to lie to an OS.
-
-13.3.38 vbeprobe
-----------------
-
- -- Command: vbeprobe [mode]
- Probe VESA BIOS EXTENSION information. If the mode MODE is
- specified, show only the information about MODE. Otherwise, this
- command lists up available VBE modes on the screen. See also *Note
- testvbe::.
-
-14 Error messages reported by GRUB
-**********************************
-
-This chapter describes error messages reported by GRUB when you
-encounter trouble. *Note Invoking the grub shell::, if your problem is
-specific to the grub shell.
-
-14.1 Errors reported by the Stage 1
-===================================
-
-The general way that the Stage 1 handles errors is to print an error
-string and then halt. Pressing `<CTRL>-<ALT>-<DEL>' will reboot.
-
- The following is a comprehensive list of error messages for the
-Stage 1:
-
-Hard Disk Error
- The stage2 or stage1.5 is being read from a hard disk, and the
- attempt to determine the size and geometry of the hard disk failed.
-
-Floppy Error
- The stage2 or stage1.5 is being read from a floppy disk, and the
- attempt to determine the size and geometry of the floppy disk
- failed. It's listed as a separate error since the probe sequence
- is different than for hard disks.
-
-Read Error
- A disk read error happened while trying to read the stage2 or
- stage1.5.
-
-Geom Error
- The location of the stage2 or stage1.5 is not in the portion of
- the disk supported directly by the BIOS read calls. This could
- occur because the BIOS translated geometry has been changed by the
- user or the disk is moved to another machine or controller after
- installation, or GRUB was not installed using itself (if it was,
- the Stage 2 version of this error would have been seen during that
- process and it would not have completed the install).
-
-14.2 Errors reported by the Stage 1.5
-=====================================
-
-The general way that the Stage 1.5 handles errors is to print an error
-number in the form `Error NUM' and then halt. Pressing
-`<CTRL>-<ALT>-<DEL>' will reboot.
-
- The error numbers correspond to the errors reported by Stage 2.
-*Note Stage2 errors::.
-
-14.3 Errors reported by the Stage 2
-===================================
-
-The general way that the Stage 2 handles errors is to abort the
-operation in question, print an error string, then (if possible) either
-continue based on the fact that an error occurred or wait for the user
-to deal with the error.
-
- The following is a comprehensive list of error messages for the
-Stage 2 (error numbers for the Stage 1.5 are listed before the colon in
-each description):
-
-1 : Filename must be either an absolute filename or blocklist
- This error is returned if a file name is requested which doesn't
- fit the syntax/rules listed in the *Note Filesystem::.
-
-2 : Bad file or directory type
- This error is returned if a file requested is not a regular file,
- but something like a symbolic link, directory, or FIFO.
-
-3 : Bad or corrupt data while decompressing file
- This error is returned if the run-length decompression code gets an
- internal error. This is usually from a corrupt file.
-
-4 : Bad or incompatible header in compressed file
- This error is returned if the file header for a supposedly
- compressed file is bad.
-
-5 : Partition table invalid or corrupt
- This error is returned if the sanity checks on the integrity of the
- partition table fail. This is a bad sign.
-
-6 : Mismatched or corrupt version of stage1/stage2
- This error is returned if the install command points to
- incompatible or corrupt versions of the stage1 or stage2. It can't
- detect corruption in general, but this is a sanity check on the
- version numbers, which should be correct.
-
-7 : Loading below 1MB is not supported
- This error is returned if the lowest address in a kernel is below
- the 1MB boundary. The Linux zImage format is a special case and
- can be handled since it has a fixed loading address and maximum
- size.
-
-8 : Kernel must be loaded before booting
- This error is returned if GRUB is told to execute the boot sequence
- without having a kernel to start.
-
-9 : Unknown boot failure
- This error is returned if the boot attempt did not succeed for
- reasons which are unknown.
-
-10 : Unsupported Multiboot features requested
- This error is returned when the Multiboot features word in the
- Multiboot header requires a feature that is not recognized. The
- point of this is that the kernel requires special handling which
- GRUB is probably unable to provide.
-
-11 : Unrecognized device string
- This error is returned if a device string was expected, and the
- string encountered didn't fit the syntax/rules listed in the *Note
- Filesystem::.
-
-12 : Invalid device requested
- This error is returned if a device string is recognizable but does
- not fall under the other device errors.
-
-13 : Invalid or unsupported executable format
- This error is returned if the kernel image being loaded is not
- recognized as Multiboot or one of the supported native formats
- (Linux zImage or bzImage, FreeBSD, or NetBSD).
-
-14 : Filesystem compatibility error, cannot read whole file
- Some of the filesystem reading code in GRUB has limits on the
- length of the files it can read. This error is returned when the
- user runs into such a limit.
-
-15 : File not found
- This error is returned if the specified file name cannot be found,
- but everything else (like the disk/partition info) is OK.
-
-16 : Inconsistent filesystem structure
- This error is returned by the filesystem code to denote an internal
- error caused by the sanity checks of the filesystem structure on
- disk not matching what it expects. This is usually caused by a
- corrupt filesystem or bugs in the code handling it in GRUB.
-
-17 : Cannot mount selected partition
- This error is returned if the partition requested exists, but the
- filesystem type cannot be recognized by GRUB.
-
-18 : Selected cylinder exceeds maximum supported by BIOS
- This error is returned when a read is attempted at a linear block
- address beyond the end of the BIOS translated area. This generally
- happens if your disk is larger than the BIOS can handle (512MB for
- (E)IDE disks on older machines or larger than 8GB in general).
-
-19 : Linux kernel must be loaded before initrd
- This error is returned if the initrd command is used before
- loading a Linux kernel.
-
-20 : Multiboot kernel must be loaded before modules
- This error is returned if the module load command is used before
- loading a Multiboot kernel. It only makes sense in this case
- anyway, as GRUB has no idea how to communicate the presence of
- such modules to a non-Multiboot-aware kernel.
-
-21 : Selected disk does not exist
- This error is returned if the device part of a device- or full
- file name refers to a disk or BIOS device that is not present or
- not recognized by the BIOS in the system.
-
-22 : No such partition
- This error is returned if a partition is requested in the device
- part of a device- or full file name which isn't on the selected
- disk.
-
-23 : Error while parsing number
- This error is returned if GRUB was expecting to read a number and
- encountered bad data.
-
-24 : Attempt to access block outside partition
- This error is returned if a linear block address is outside of the
- disk partition. This generally happens because of a corrupt
- filesystem on the disk or a bug in the code handling it in GRUB
- (it's a great debugging tool).
-
-25 : Disk read error
- This error is returned if there is a disk read error when trying to
- probe or read data from a particular disk.
-
-26 : Too many symbolic links
- This error is returned if the link count is beyond the maximum
- (currently 5), possibly the symbolic links are looped.
-
-27 : Unrecognized command
- This error is returned if an unrecognized command is entered on the
- command-line or in a boot sequence section of a configuration file
- and that entry is selected.
-
-28 : Selected item cannot fit into memory
- This error is returned if a kernel, module, or raw file load
- command is either trying to load its data such that it won't fit
- into memory or it is simply too big.
-
-29 : Disk write error
- This error is returned if there is a disk write error when trying
- to write to a particular disk. This would generally only occur
- during an install of set active partition command.
-
-30 : Invalid argument
- This error is returned if an argument specified to a command is
- invalid.
-
-31 : File is not sector aligned
- This error may occur only when you access a ReiserFS partition by
- block-lists (e.g. the command `install'). In this case, you should
- mount the partition with the `-o notail' option.
-
-32 : Must be authenticated
- This error is returned if you try to run a locked entry. You should
- enter a correct password before running such an entry.
-
-33 : Serial device not configured
- This error is returned if you try to change your terminal to a
- serial one before initializing any serial device.
-
-34 : No spare sectors on the disk
- This error is returned if a disk doesn't have enough spare space.
- This happens when you try to embed Stage 1.5 into the unused
- sectors after the MBR, but the first partition starts right after
- the MBR or they are used by EZ-BIOS.
-
-15 Invoking the grub shell
-**************************
-
-This chapter documents the grub shell `grub'. Note that the grub shell
-is an emulator; it doesn't run under the native environment, so it
-sometimes does something wrong. Therefore, you shouldn't trust it too
-much. If there is anything wrong with it, don't hesitate to try the
-native GRUB environment, especially when it guesses a wrong map between
-BIOS drives and OS devices.
-
-15.1 Introduction into the grub shell
-=====================================
-
-You can use the command `grub' for installing GRUB under your operating
-systems and for a testbed when you add a new feature into GRUB or when
-fixing a bug. `grub' is almost the same as the Stage 2, and, in fact,
-it shares the source code with the Stage 2 and you can use the same
-commands (*note Commands::) in `grub'. It is emulated by replacing BIOS
-calls with UNIX system calls and libc functions.
-
- The command `grub' accepts the following options:
-
-`--help'
- Print a summary of the command-line options and exit.
-
-`--version'
- Print the version number of GRUB and exit.
-
-`--verbose'
- Print some verbose messages for debugging purpose.
-
-`--device-map=FILE'
- Use the device map file FILE. The format is described in *Note
- Device map::.
-
-`--no-floppy'
- Do not probe any floppy drive. This option has no effect if the
- option `--device-map' is specified (*note Device map::).
-
-`--probe-second-floppy'
- Probe the second floppy drive. If this option is not specified,
- the grub shell does not probe it, as that sometimes takes a long
- time. If you specify the device map file (*note Device map::), the
- grub shell just ignores this option.
-
-`--config-file=FILE'
- Read the configuration file FILE instead of `/boot/grub/menu.lst'.
- The format is the same as the normal GRUB syntax. See *Note
- Filesystem::, for more information.
-
-`--boot-drive=DRIVE'
- Set the stage2 BOOT_DRIVE to DRIVE. This argument should be an
- integer (decimal, octal or hexadecimal).
-
-`--install-partition=PAR'
- Set the stage2 INSTALL_PARTITION to PAR. This argument should be
- an integer (decimal, octal or hexadecimal).
-
-`--no-config-file'
- Do not use the configuration file even if it can be read.
-
-`--no-curses'
- Do not use the screen handling interface by the curses even if it
- is available.
-
-`--batch'
- This option has the same meaning as `--no-config-file --no-curses'.
-
-`--read-only'
- Disable writing to any disk.
-
-`--hold'
- Wait until a debugger will attach. This option is useful when you
- want to debug the startup code.
-
-15.2 How to install GRUB via `grub'
-===================================
-
-The installation procedure is the same as under the "native" Stage 2.
-*Note Installation::, for more information. The command `grub'-specific
-information is described here.
-
- What you should be careful about is "buffer cache". `grub' makes use
-of raw devices instead of filesystems that your operating systems
-serve, so there exists a potential problem that some cache
-inconsistency may corrupt your filesystems. What we recommend is:
-
- * If you can unmount drives to which GRUB may write any amount of
- data, unmount them before running `grub'.
-
- * If a drive cannot be unmounted but can be mounted with the
- read-only flag, mount it in read-only mode. That should be secure.
-
- * If a drive must be mounted with the read-write flag, make sure
- that no activity is being done on it while the command `grub' is
- running.
-
- * Reboot your operating system as soon as possible. This is probably
- not required if you follow the rules above, but reboot is the most
- secure way.
-
- In addition, enter the command `quit' when you finish the
-installation. That is _very important_ because `quit' makes the buffer
-cache consistent. Do not push <C-c>.
-
- If you want to install GRUB non-interactively, specify `--batch'
-option in the command-line. This is a simple example:
-
- #!/bin/sh
-
- # Use /usr/sbin/grub if you are on an older system.
- /sbin/grub --batch <<EOT 1>/dev/null 2>/dev/null
- root (hd0,0)
- setup (hd0)
- quit
- EOT
-
-15.3 The map between BIOS drives and OS devices
-===============================================
-
-When you specify the option `--device-map' (*note Basic usage::), the
-grub shell creates the "device map file" automatically unless it
-already exists. The file name `/boot/grub/device.map' is preferred.
-
- If the device map file exists, the grub shell reads it to map BIOS
-drives to OS devices. This file consists of lines like this:
-
- DEVICE FILE
-
- DEVICE is a drive specified in the GRUB syntax (*note Device
-syntax::), and FILE is an OS file, which is normally a device file.
-
- The reason why the grub shell gives you the device map file is that
-it cannot guess the map between BIOS drives and OS devices correctly in
-some environments. For example, if you exchange the boot sequence
-between IDE and SCSI in your BIOS, it gets the order wrong.
-
- Thus, edit the file if the grub shell makes a mistake. You can put
-any comments in the file if needed, as the grub shell assumes that a
-line is just a comment if the first character is `#'.
-
-16 Invoking grub-install
-************************
-
-The program `grub-install' installs GRUB on your drive using the grub
-shell (*note Invoking the grub shell::). You must specify the device
-name on which you want to install GRUB, like this:
-
- grub-install INSTALL_DEVICE
-
- The device name INSTALL_DEVICE is an OS device name or a GRUB device
-name.
-
- `grub-install' accepts the following options:
-
-`--help'
- Print a summary of the command-line options and exit.
-
-`--version'
- Print the version number of GRUB and exit.
-
-`--force-lba'
- Force GRUB to use LBA mode even for a buggy BIOS. Use this option
- only if your BIOS doesn't work properly in LBA mode even though it
- supports LBA mode.
-
-`--root-directory=DIR'
- Install GRUB images under the directory DIR instead of the root
- directory. This option is useful when you want to install GRUB
- into a separate partition or a removable disk. Here is an example
- in which you have a separate "boot" partition which is mounted on
- `/boot':
-
- grub-install --root-directory=/boot hd0
-
-`--grub-shell=FILE'
- Use FILE as the grub shell. You can append arbitrary options to
- FILE after the file name, like this:
-
- grub-install --grub-shell="grub --read-only" /dev/fd0
-
-`--recheck'
- Recheck the device map, even if `/boot/grub/device.map' already
- exists. You should use this option whenever you add/remove a disk
- into/from your computer.
-
-17 Invoking grub-md5-crypt
-**************************
-
-The program `grub-md5-crypt' encrypts a password in MD5 format. This
-is just a frontend of the grub shell (*note Invoking the grub shell::).
-Passwords encrypted by this program can be used with the command
-`password' (*note password::).
-
- `grub-md5-crypt' accepts the following options:
-
-`--help'
- Print a summary of the command-line options and exit.
-
-`--version'
- Print the version information and exit.
-
-`--grub-shell=FILE'
- Use FILE as the grub shell.
-
-18 Invoking grub-terminfo
-*************************
-
-The program `grub-terminfo' generates a terminfo command from a
-terminfo name (*note terminfo::). The result can be used in the
-configuration file, to define escape sequences. Because GRUB assumes
-that your terminal is vt100-compatible by default, this would be useful
-only if your terminal is uncommon (such as vt52).
-
- `grub-terminfo' accepts the following options:
-
-`--help'
- Print a summary of the command-line options and exit.
-
-`--version'
- Print the version information and exit.
-
- You must specify one argument to this command. For example:
-
- grub-terminfo vt52
-
-19 Invoking grub-set-default
-****************************
-
-The program `grub-set-default' sets the default boot entry for GRUB.
-This automatically creates a file named `default' under your GRUB
-directory (i.e. `/boot/grub'), if it is not present. This file is used
-to determine the default boot entry when GRUB boots up your system when
-you use `default saved' in your configuration file (*note default::),
-and to save next default boot entry when you use `savedefault' in a
-boot entry (*note savedefault::).
-
- `grub-set-default' accepts the following options:
-
-`--help'
- Print a summary of the command-line options and exit.
-
-`--version'
- Print the version information and exit.
-
-`--root-directory=DIR'
- Use the directory DIR instead of the root directory (i.e. `/') to
- define the location of the default file. This is useful when you
- mount a disk which is used for another system.
-
- You must specify a single argument to `grub-set-default'. This
-argument is normally the number of a default boot entry. For example,
-if you have this configuration file:
-
- default saved
- timeout 10
-
- title GNU/Hurd
- root (hd0,0)
- ...
-
- title GNU/Linux
- root (hd0,1)
- ...
-
- and if you want to set the next default boot entry to GNU/Linux, you
-may execute this command:
-
- grub-set-default 1
-
- Because the entry for GNU/Linux is `1'. Note that entries are
-counted from zero. So, if you want to specify GNU/Hurd here, then you
-should specify `0'.
-
- This feature is very useful if you want to test a new kernel or to
-make your system quite robust. *Note Making your system robust::, for
-more hints about how to set up a robust system.
-
-20 Invoking mbchk
-*****************
-
-The program `mbchk' checks for the format of a Multiboot kernel. We
-recommend using this program before booting your own kernel by GRUB.
-
- `mbchk' accepts the following options:
-
-`--help'
- Print a summary of the command-line options and exit.
-
-`--version'
- Print the version number of GRUB and exit.
-
-`--quiet'
- Suppress all normal output.
-
-Appendix A How to obtain and build GRUB
-***************************************
-
- *Caution:* GRUB requires binutils-2.9.1.0.23 or later because the
- GNU assembler has been changed so that it can produce real 16bits
- machine code between 2.9.1 and 2.9.1.0.x. See
- `http://sources.redhat.com/binutils/', to obtain information on
- how to get the latest version.
-
- GRUB is available from the GNU alpha archive site
-`ftp://alpha.gnu.org/gnu/grub' or any of its mirrors. The file will be
-named grub-version.tar.gz. The current version is 0.97, so the file you
-should grab is:
-
- `ftp://alpha.gnu.org/gnu/grub/grub-0.97.tar.gz'
-
- To unbundle GRUB use the instruction:
-
- zcat grub-0.97.tar.gz | tar xvf -
-
- which will create a directory called `grub-0.97' with all the
-sources. You can look at the file `INSTALL' for detailed instructions
-on how to build and install GRUB, but you should be able to just do:
-
- cd grub-0.97
- ./configure
- make install
-
- This will install the grub shell `grub' (*note Invoking the grub
-shell::), the Multiboot checker `mbchk' (*note Invoking mbchk::), and
-the GRUB images. This will also install the GRUB manual.
-
- Also, the latest version is available from the CVS. See
-`http://savannah.gnu.org/cvs/?group=grub' for more information.
-
-Appendix B Reporting bugs
-*************************
-
-These are the guideline for how to report bugs. Take a look at this
-list below before you submit bugs:
-
- 1. Before getting unsettled, read this manual through and through.
- Also, see the GNU GRUB FAQ
- (http://www.gnu.org/software/grub/grub-faq.html).
-
- 2. Always mention the information on your GRUB. The version number
- and the configuration are quite important. If you build it
- yourself, write the options specified to the configure script and
- your operating system, including the versions of gcc and binutils.
-
- 3. If you have trouble with the installation, inform us of how you
- installed GRUB. Don't omit error messages, if any. Just `GRUB hangs
- up when it boots' is not enough.
-
- The information on your hardware is also essential. These are
- especially important: the geometries and the partition tables of
- your hard disk drives and your BIOS.
-
- 4. If GRUB cannot boot your operating system, write down _everything_
- you see on the screen. Don't paraphrase them, like `The foo OS
- crashes with GRUB, even though it can boot with the bar boot
- loader just fine'. Mention the commands you executed, the messages
- printed by them, and information on your operating system
- including the version number.
-
- 5. Explain what you wanted to do. It is very useful to know your
- purpose and your wish, and how GRUB didn't satisfy you.
-
- 6. If you can investigate the problem yourself, please do. That will
- give you and us much more information on the problem. Attaching a
- patch is even better.
-
- When you attach a patch, make the patch in unified diff format, and
- write ChangeLog entries. But, even when you make a patch, don't
- forget to explain the problem, so that we can understand what your
- patch is for.
-
- 7. Write down anything that you think might be related. Please
- understand that we often need to reproduce the same problem you
- encounterred in our environment. So your information should be
- sufficient for us to do the same thing--Don't forget that we
- cannot see your computer directly. If you are not sure whether to
- state a fact or leave it out, state it! Reporting too many things
- is much better than omitting something important.
-
- If you follow the guideline above, submit a report to the Bug
-Tracking System (http://savannah.gnu.org/bugs/?group=grub).
-Alternatively, you can submit a report via electronic mail to
-<bug-grub@gnu.org>, but we strongly recommend that you use the Bug
-Tracking System, because e-mail can be passed over easily.
-
- Once we get your report, we will try to fix the bugs.
-
-Appendix C Where GRUB will go
-*****************************
-
-We started the next generation of GRUB, GRUB 2. This will include
-internationalization, dynamic module loading, real memory management,
-multiple architecture support, a scripting language, and many other
-nice feature. If you are interested in the development of GRUB 2, take
-a look at the homepage (http://www.gnu.org/software/grub/grub.html).
-
-Appendix D Hacking GRUB
-***********************
-
-This chapter documents the user-invisible aspect of GRUB.
-
- As a general rule of software development, it is impossible to keep
-the descriptions of the internals up-to-date, and it is quite hard to
-document everything. So refer to the source code, whenever you are not
-satisfied with this documentation. Please assume that this gives just
-hints to you.
-
-D.1 The memory map of various components
-========================================
-
-GRUB consists of two distinct components, called "stages", which are
-loaded at different times in the boot process. Because they run
-mutual-exclusively, sometimes a memory area overlaps with another
-memory area. And, even in one stage, a single memory area can be used
-for various purposes, because their usages are mutually exclusive.
-
- Here is the memory map of the various components:
-
-0 to 4K-1
- BIOS and real mode interrupts
-
-0x07BE to 0x07FF
- Partition table passed to another boot loader
-
-down from 8K-1
- Real mode stack
-
-0x2000 to ?
- The optional Stage 1.5 is loaded here
-
-0x2000 to 0x7FFF
- Command-line buffer for Multiboot kernels and modules
-
-0x7C00 to 0x7DFF
- Stage 1 is loaded here by BIOS or another boot loader
-
-0x7F00 to 0x7F42
- LBA drive parameters
-
-0x8000 to ?
- Stage2 is loaded here
-
-The end of Stage 2 to 416K-1
- Heap, in particular used for the menu
-
-down from 416K-1
- Protected mode stack
-
-416K to 448K-1
- Filesystem buffer
-
-448K to 479.5K-1
- Raw device buffer
-
-479.5K to 480K-1
- 512-byte scratch area
-
-480K to 512K-1
- Buffers for various functions, such as password, command-line, cut
- and paste, and completion.
-
-The last 1K of lower memory
- Disk swapping code and data
-
- See the file `stage2/shared.h', for more information.
-
-D.2 Embedded variables in GRUB
-==============================
-
-Stage 1 and Stage 2 have embedded variables whose locations are
-well-defined, so that the installation can patch the binary file
-directly without recompilation of the stages.
-
- In Stage 1, these are defined:
-
-`0x3E'
- The version number (not GRUB's, but the installation mechanism's).
-
-`0x40'
- The boot drive. If it is 0xFF, use a drive passed by BIOS.
-
-`0x41'
- The flag for if forcing LBA.
-
-`0x42'
- The starting address of Stage 2.
-
-`0x44'
- The first sector of Stage 2.
-
-`0x48'
- The starting segment of Stage 2.
-
-`0x1FE'
- The signature (`0xAA55').
-
- See the file `stage1/stage1.S', for more information.
-
- In the first sector of Stage 1.5 and Stage 2, the block lists are
-recorded between `firstlist' and `lastlist'. The address of `lastlist'
-is determined when assembling the file `stage2/start.S'.
-
- The trick here is that it is actually read backward, and the first
-8-byte block list is not read here, but after the pointer is decremented
-8 bytes, then after reading it, it decrements again, reads, and so on,
-until it is finished. The terminating condition is when the number of
-sectors to be read in the next block list is zero.
-
- The format of a block list can be seen from the example in the code
-just before the `firstlist' label. Note that it is always from the
-beginning of the disk, but _not_ relative to the partition boundaries.
-
- In the second sector of Stage 1.5 and Stage 2, these are defined:
-
-`0x6'
- The version number (likewise, the installation mechanism's).
-
-`0x8'
- The installed partition.
-
-`0xC'
- The saved entry number.
-
-`0x10'
- The identifier.
-
-`0x11'
- The flag for if forcing LBA.
-
-`0x12'
- The version string (GRUB's).
-
-`0x12' + "the length of the version string"
- The name of a configuration file.
-
- See the file `stage2/asm.S', for more information.
-
-D.3 The generic interface for filesystems
-=========================================
-
-For any particular partition, it is presumed that only one of the
-"normal" filesystems such as FAT, FFS, or ext2fs can be used, so there
-is a switch table managed by the functions in `disk_io.c'. The notation
-is that you can only "mount" one at a time.
-
- The block list filesystem has a special place in the system. In
-addition to the "normal" filesystem (or even without one mounted), you
-can access disk blocks directly (in the indicated partition) via the
-block list notation. Using the block list filesystem doesn't effect any
-other filesystem mounts.
-
- The variables which can be read by the filesystem backend are:
-
-`current_drive'
- The current BIOS drive number (numbered from 0, if a floppy, and
- numbered from 0x80, if a hard disk).
-
-`current_partition'
- The current partition number.
-
-`current_slice'
- The current partition type.
-
-`saved_drive'
- The "drive" part of the root device.
-
-`saved_partition'
- The "partition" part of the root device.
-
-`part_start'
- The current partition starting address, in sectors.
-
-`part_length'
- The current partition length, in sectors.
-
-`print_possibilities'
- True when the `dir' function should print the possible completions
- of a file, and false when it should try to actually open a file of
- that name.
-
-`FSYS_BUF'
- Filesystem buffer which is 32K in size, to use in any way which the
- filesystem backend desires.
-
- The variables which need to be written by a filesystem backend are:
-
-`filepos'
- The current position in the file, in sectors.
-
- *Caution:* the value of FILEPOS can be changed out from under the
- filesystem code in the current implementation. Don't depend on it
- being the same for later calls into the backend code!
-
-`filemax'
- The length of the file.
-
-`disk_read_func'
- The value of DISK_READ_HOOK _only_ during reading of data for the
- file, not any other fs data, inodes, FAT tables, whatever, then
- set to `NULL' at all other times (it will be `NULL' by default).
- If this isn't done correctly, then the `testload' and `install'
- commands won't work correctly.
-
- The functions expected to be used by the filesystem backend are:
-
-`devread'
- Only read sectors from within a partition. Sector 0 is the first
- sector in the partition.
-
-`grub_read'
- If the backend uses the block list code, then `grub_read' can be
- used, after setting BLOCK_FILE to 1.
-
-`print_a_completion'
- If PRINT_POSSIBILITIES is true, call `print_a_completion' for each
- possible file name. Otherwise, the file name completion won't work.
-
- The functions expected to be defined by the filesystem backend are
-described at least moderately in the file `filesys.h'. Their usage is
-fairly evident from their use in the functions in `disk_io.c', look for
-the use of the FSYS_TABLE array.
-
- *Caution:* The semantics are such that then `mount'ing the
-filesystem, presume the filesystem buffer `FSYS_BUF' is corrupted, and
-(re-)load all important contents. When opening and reading a file,
-presume that the data from the `mount' is available, and doesn't get
-corrupted by the open/read (i.e. multiple opens and/or reads will be
-done with only one mount if in the same filesystem).
-
-D.4 The generic interface for built-ins
-=======================================
-
-GRUB built-in commands are defined in a uniformal interface, whether
-they are menu-specific or can be used anywhere. The definition of a
-builtin command consists of two parts: the code itself and the table of
-the information.
-
- The code must be a function which takes two arguments, a command-line
-string and flags, and returns an `int' value. The "flags" argument
-specifies how the function is called, using a bit mask. The return
-value must be zero if successful, otherwise non-zero. So it is normally
-enough to return ERRNUM.
-
- The table of the information is represented by the structure `struct
-builtin', which contains the name of the command, a pointer to the
-function, flags, a short description of the command and a long
-description of the command. Since the descriptions are used only for
-help messages interactively, you don't have to define them, if the
-command may not be called interactively (such as `title').
-
- The table is finally registered in the table BUILTIN_TABLE, so that
-`run_script' and `enter_cmdline' can find the command. See the files
-`cmdline.c' and `builtins.c', for more details.
-
-D.5 The bootstrap mechanism used in GRUB
-========================================
-
-The disk space can be used in a boot loader is very restricted because
-a MBR (*note MBR::) is only 512 bytes but it also contains a partition
-table (*note Partition table::) and a BPB. So the question is how to
-make a boot loader code enough small to be fit in a MBR.
-
- However, GRUB is a very large program, so we break GRUB into 2 (or 3)
-distinct components, "Stage 1" and "Stage 2" (and optionally "Stage
-1.5"). *Note Memory map::, for more information.
-
- We embed Stage 1 in a MBR or in the boot sector of a partition, and
-place Stage 2 in a filesystem. The optional Stage 1.5 can be installed
-in a filesystem, in the "boot loader" area in a FFS or a ReiserFS, and
-in the sectors right after a MBR, because Stage 1.5 is enough small and
-the sectors right after a MBR is normally an unused region. The size of
-this region is the number of sectors per head minus 1.
-
- Thus, all Stage1 must do is just load Stage2 or Stage1.5. But even if
-Stage 1 needs not to support the user interface or the filesystem
-interface, it is impossible to make Stage 1 less than 400 bytes, because
-GRUB should support both the CHS mode and the LBA mode (*note Low-level
-disk I/O::).
-
- The solution used by GRUB is that Stage 1 loads only the first
-sector of Stage 2 (or Stage 1.5) and Stage 2 itself loads the rest. The
-flow of Stage 1 is:
-
- 1. Initialize the system briefly.
-
- 2. Detect the geometry and the accessing mode of the "loading drive".
-
- 3. Load the first sector of Stage 2.
-
- 4. Jump to the starting address of the Stage 2.
-
- The flow of Stage 2 (and Stage 1.5) is:
-
- 1. Load the rest of itself to the real starting address, that is, the
- starting address plus 512 bytes. The block lists are stored in the
- last part of the first sector.
-
- 2. Long jump to the real starting address.
-
- Note that Stage 2 (or Stage 1.5) does not probe the geometry or the
-accessing mode of the "loading drive", since Stage 1 has already probed
-them.
-
-D.6 How to probe I/O ports used by INT 13H
-==========================================
-
-FIXME: I will write this chapter after implementing the new technique.
-
-D.7 How to detect all installed RAM
-===================================
-
-FIXME: I doubt if Erich didn't write this chapter only himself wholly,
-so I will rewrite this chapter.
-
-D.8 INT 13H disk I/O interrupts
-===============================
-
-FIXME: I'm not sure where some part of the original chapter is derived,
-so I will rewrite this chapter.
-
-D.9 The structure of Master Boot Record
-=======================================
-
-FIXME: Likewise.
-
-D.10 The format of partition tables
-===================================
-
-FIXME: Probably the original chapter is derived from "How It Works", so
-I will rewrite this chapter.
-
-D.11 Where and how you should send patches
-==========================================
-
-When you write patches for GRUB, please send them to the mailing list
-<bug-grub@gnu.org>. Here is the list of items of which you should take
-care:
-
- * Please make your patch as small as possible. Generally, it is not
- a good thing to make one big patch which changes many things.
- Instead, segregate features and produce many patches.
-
- * Use as late code as possible, for the original code. The CVS
- repository always has the current version (*note Obtaining and
- Building GRUB::).
-
- * Write ChangeLog entries. *Note Change Logs: (standards)Change
- Logs, if you don't know how to write ChangeLog.
-
- * Make patches in unified diff format. `diff -urN' is appropriate in
- most cases.
-
- * Don't make patches reversely. Reverse patches are difficult to
- read and use.
-
- * Be careful enough of the license term and the copyright. Because
- GRUB is under GNU General Public License, you may not steal code
- from software whose license is incompatible against GPL. And, if
- you copy code written by others, you must not ignore their
- copyrights. Feel free to ask GRUB maintainers, whenever you are
- not sure what you should do.
-
- * If your patch is too large to send in e-mail, put it at somewhere
- we can see. Usually, you shouldn't send e-mail over 20K.
-
-Appendix E Copying This Manual
-******************************
-
-E.1 GNU Free Documentation License
-==================================
-
- Version 1.2, November 2002
-
- Copyright (C) 2000,2001,2002 Free Software Foundation, Inc.
- 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
-
- Everyone is permitted to copy and distribute verbatim copies
- of this license document, but changing it is not allowed.
-
- 0. PREAMBLE
-
- The purpose of this License is to make a manual, textbook, or other
- functional and useful document "free" in the sense of freedom: to
- assure everyone the effective freedom to copy and redistribute it,
- with or without modifying it, either commercially or
- noncommercially. Secondarily, this License preserves for the
- author and publisher a way to get credit for their work, while not
- being considered responsible for modifications made by others.
-
- This License is a kind of "copyleft", which means that derivative
- works of the document must themselves be free in the same sense.
- It complements the GNU General Public License, which is a copyleft
- license designed for free software.
-
- We have designed this License in order to use it for manuals for
- free software, because free software needs free documentation: a
- free program should come with manuals providing the same freedoms
- that the software does. But this License is not limited to
- software manuals; it can be used for any textual work, regardless
- of subject matter or whether it is published as a printed book.
- We recommend this License principally for works whose purpose is
- instruction or reference.
-
- 1. APPLICABILITY AND DEFINITIONS
-
- This License applies to any manual or other work, in any medium,
- that contains a notice placed by the copyright holder saying it
- can be distributed under the terms of this License. Such a notice
- grants a world-wide, royalty-free license, unlimited in duration,
- to use that work under the conditions stated herein. The
- "Document", below, refers to any such manual or work. Any member
- of the public is a licensee, and is addressed as "you". You
- accept the license if you copy, modify or distribute the work in a
- way requiring permission under copyright law.
-
- A "Modified Version" of the Document means any work containing the
- Document or a portion of it, either copied verbatim, or with
- modifications and/or translated into another language.
-
- A "Secondary Section" is a named appendix or a front-matter section
- of the Document that deals exclusively with the relationship of the
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- subject (or to related matters) and contains nothing that could
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- regarding them.
-
- The "Invariant Sections" are certain Secondary Sections whose
- titles are designated, as being those of Invariant Sections, in
- the notice that says that the Document is released under this
- License. If a section does not fit the above definition of
- Secondary then it is not allowed to be designated as Invariant.
- The Document may contain zero Invariant Sections. If the Document
- does not identify any Invariant Sections then there are none.
-
- The "Cover Texts" are certain short passages of text that are
- listed, as Front-Cover Texts or Back-Cover Texts, in the notice
- that says that the Document is released under this License. A
- Front-Cover Text may be at most 5 words, and a Back-Cover Text may
- be at most 25 words.
-
- A "Transparent" copy of the Document means a machine-readable copy,
- represented in a format whose specification is available to the
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- straightforwardly with generic text editors or (for images
- composed of pixels) generic paint programs or (for drawings) some
- widely available drawing editor, and that is suitable for input to
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- markup, has been arranged to thwart or discourage subsequent
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- copy that is not "Transparent" is called "Opaque".
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- available, and the machine-generated HTML, PostScript or PDF
- produced by some word processors for output purposes only.
-
- The "Title Page" means, for a printed book, the title page itself,
- plus such following pages as are needed to hold, legibly, the
- material this License requires to appear in the title page. For
- works in formats which do not have any title page as such, "Title
- Page" means the text near the most prominent appearance of the
- work's title, preceding the beginning of the body of the text.
-
- A section "Entitled XYZ" means a named subunit of the Document
- whose title either is precisely XYZ or contains XYZ in parentheses
- following text that translates XYZ in another language. (Here XYZ
- stands for a specific section name mentioned below, such as
- "Acknowledgements", "Dedications", "Endorsements", or "History".)
- To "Preserve the Title" of such a section when you modify the
- Document means that it remains a section "Entitled XYZ" according
- to this definition.
-
- The Document may include Warranty Disclaimers next to the notice
- which states that this License applies to the Document. These
- Warranty Disclaimers are considered to be included by reference in
- this License, but only as regards disclaiming warranties: any other
- implication that these Warranty Disclaimers may have is void and
- has no effect on the meaning of this License.
-
- 2. VERBATIM COPYING
-
- You may copy and distribute the Document in any medium, either
- commercially or noncommercially, provided that this License, the
- copyright notices, and the license notice saying this License
- applies to the Document are reproduced in all copies, and that you
- add no other conditions whatsoever to those of this License. You
- may not use technical measures to obstruct or control the reading
- or further copying of the copies you make or distribute. However,
- you may accept compensation in exchange for copies. If you
- distribute a large enough number of copies you must also follow
- the conditions in section 3.
-
- You may also lend copies, under the same conditions stated above,
- and you may publicly display copies.
-
- 3. COPYING IN QUANTITY
-
- If you publish printed copies (or copies in media that commonly
- have printed covers) of the Document, numbering more than 100, and
- the Document's license notice requires Cover Texts, you must
- enclose the copies in covers that carry, clearly and legibly, all
- these Cover Texts: Front-Cover Texts on the front cover, and
- Back-Cover Texts on the back cover. Both covers must also clearly
- and legibly identify you as the publisher of these copies. The
- front cover must present the full title with all words of the
- title equally prominent and visible. You may add other material
- on the covers in addition. Copying with changes limited to the
- covers, as long as they preserve the title of the Document and
- satisfy these conditions, can be treated as verbatim copying in
- other respects.
-
- If the required texts for either cover are too voluminous to fit
- legibly, you should put the first ones listed (as many as fit
- reasonably) on the actual cover, and continue the rest onto
- adjacent pages.
-
- If you publish or distribute Opaque copies of the Document
- numbering more than 100, you must either include a
- machine-readable Transparent copy along with each Opaque copy, or
- state in or with each Opaque copy a computer-network location from
- which the general network-using public has access to download
- using public-standard network protocols a complete Transparent
- copy of the Document, free of added material. If you use the
- latter option, you must take reasonably prudent steps, when you
- begin distribution of Opaque copies in quantity, to ensure that
- this Transparent copy will remain thus accessible at the stated
- location until at least one year after the last time you
- distribute an Opaque copy (directly or through your agents or
- retailers) of that edition to the public.
-
- It is requested, but not required, that you contact the authors of
- the Document well before redistributing any large number of
- copies, to give them a chance to provide you with an updated
- version of the Document.
-
- 4. MODIFICATIONS
-
- You may copy and distribute a Modified Version of the Document
- under the conditions of sections 2 and 3 above, provided that you
- release the Modified Version under precisely this License, with
- the Modified Version filling the role of the Document, thus
- licensing distribution and modification of the Modified Version to
- whoever possesses a copy of it. In addition, you must do these
- things in the Modified Version:
-
- A. Use in the Title Page (and on the covers, if any) a title
- distinct from that of the Document, and from those of
- previous versions (which should, if there were any, be listed
- in the History section of the Document). You may use the
- same title as a previous version if the original publisher of
- that version gives permission.
-
- B. List on the Title Page, as authors, one or more persons or
- entities responsible for authorship of the modifications in
- the Modified Version, together with at least five of the
- principal authors of the Document (all of its principal
- authors, if it has fewer than five), unless they release you
- from this requirement.
-
- C. State on the Title page the name of the publisher of the
- Modified Version, as the publisher.
-
- D. Preserve all the copyright notices of the Document.
-
- E. Add an appropriate copyright notice for your modifications
- adjacent to the other copyright notices.
-
- F. Include, immediately after the copyright notices, a license
- notice giving the public permission to use the Modified
- Version under the terms of this License, in the form shown in
- the Addendum below.
-
- G. Preserve in that license notice the full lists of Invariant
- Sections and required Cover Texts given in the Document's
- license notice.
-
- H. Include an unaltered copy of this License.
-
- I. Preserve the section Entitled "History", Preserve its Title,
- and add to it an item stating at least the title, year, new
- authors, and publisher of the Modified Version as given on
- the Title Page. If there is no section Entitled "History" in
- the Document, create one stating the title, year, authors,
- and publisher of the Document as given on its Title Page,
- then add an item describing the Modified Version as stated in
- the previous sentence.
-
- J. Preserve the network location, if any, given in the Document
- for public access to a Transparent copy of the Document, and
- likewise the network locations given in the Document for
- previous versions it was based on. These may be placed in
- the "History" section. You may omit a network location for a
- work that was published at least four years before the
- Document itself, or if the original publisher of the version
- it refers to gives permission.
-
- K. For any section Entitled "Acknowledgements" or "Dedications",
- Preserve the Title of the section, and preserve in the
- section all the substance and tone of each of the contributor
- acknowledgements and/or dedications given therein.
-
- L. Preserve all the Invariant Sections of the Document,
- unaltered in their text and in their titles. Section numbers
- or the equivalent are not considered part of the section
- titles.
-
- M. Delete any section Entitled "Endorsements". Such a section
- may not be included in the Modified Version.
-
- N. Do not retitle any existing section to be Entitled
- "Endorsements" or to conflict in title with any Invariant
- Section.
-
- O. Preserve any Warranty Disclaimers.
-
- If the Modified Version includes new front-matter sections or
- appendices that qualify as Secondary Sections and contain no
- material copied from the Document, you may at your option
- designate some or all of these sections as invariant. To do this,
- add their titles to the list of Invariant Sections in the Modified
- Version's license notice. These titles must be distinct from any
- other section titles.
-
- You may add a section Entitled "Endorsements", provided it contains
- nothing but endorsements of your Modified Version by various
- parties--for example, statements of peer review or that the text
- has been approved by an organization as the authoritative
- definition of a standard.
-
- You may add a passage of up to five words as a Front-Cover Text,
- and a passage of up to 25 words as a Back-Cover Text, to the end
- of the list of Cover Texts in the Modified Version. Only one
- passage of Front-Cover Text and one of Back-Cover Text may be
- added by (or through arrangements made by) any one entity. If the
- Document already includes a cover text for the same cover,
- previously added by you or by arrangement made by the same entity
- you are acting on behalf of, you may not add another; but you may
- replace the old one, on explicit permission from the previous
- publisher that added the old one.
-
- The author(s) and publisher(s) of the Document do not by this
- License give permission to use their names for publicity for or to
- assert or imply endorsement of any Modified Version.
-
- 5. COMBINING DOCUMENTS
-
- You may combine the Document with other documents released under
- this License, under the terms defined in section 4 above for
- modified versions, provided that you include in the combination
- all of the Invariant Sections of all of the original documents,
- unmodified, and list them all as Invariant Sections of your
- combined work in its license notice, and that you preserve all
- their Warranty Disclaimers.
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- The combined work need only contain one copy of this License, and
- multiple identical Invariant Sections may be replaced with a single
- copy. If there are multiple Invariant Sections with the same name
- but different contents, make the title of each such section unique
- by adding at the end of it, in parentheses, the name of the
- original author or publisher of that section if known, or else a
- unique number. Make the same adjustment to the section titles in
- the list of Invariant Sections in the license notice of the
- combined work.
-
- In the combination, you must combine any sections Entitled
- "History" in the various original documents, forming one section
- Entitled "History"; likewise combine any sections Entitled
- "Acknowledgements", and any sections Entitled "Dedications". You
- must delete all sections Entitled "Endorsements."
-
- 6. COLLECTIONS OF DOCUMENTS
-
- You may make a collection consisting of the Document and other
- documents released under this License, and replace the individual
- copies of this License in the various documents with a single copy
- that is included in the collection, provided that you follow the
- rules of this License for verbatim copying of each of the
- documents in all other respects.
-
- You may extract a single document from such a collection, and
- distribute it individually under this License, provided you insert
- a copy of this License into the extracted document, and follow
- this License in all other respects regarding verbatim copying of
- that document.
-
- 7. AGGREGATION WITH INDEPENDENT WORKS
-
- A compilation of the Document or its derivatives with other
- separate and independent documents or works, in or on a volume of
- a storage or distribution medium, is called an "aggregate" if the
- copyright resulting from the compilation is not used to limit the
- legal rights of the compilation's users beyond what the individual
- works permit. When the Document is included in an aggregate, this
- License does not apply to the other works in the aggregate which
- are not themselves derivative works of the Document.
-
- If the Cover Text requirement of section 3 is applicable to these
- copies of the Document, then if the Document is less than one half
- of the entire aggregate, the Document's Cover Texts may be placed
- on covers that bracket the Document within the aggregate, or the
- electronic equivalent of covers if the Document is in electronic
- form. Otherwise they must appear on printed covers that bracket
- the whole aggregate.
-
- 8. TRANSLATION
-
- Translation is considered a kind of modification, so you may
- distribute translations of the Document under the terms of section
- 4. Replacing Invariant Sections with translations requires special
- permission from their copyright holders, but you may include
- translations of some or all Invariant Sections in addition to the
- original versions of these Invariant Sections. You may include a
- translation of this License, and all the license notices in the
- Document, and any Warranty Disclaimers, provided that you also
- include the original English version of this License and the
- original versions of those notices and disclaimers. In case of a
- disagreement between the translation and the original version of
- this License or a notice or disclaimer, the original version will
- prevail.
-
- If a section in the Document is Entitled "Acknowledgements",
- "Dedications", or "History", the requirement (section 4) to
- Preserve its Title (section 1) will typically require changing the
- actual title.
-
- 9. TERMINATION
-
- You may not copy, modify, sublicense, or distribute the Document
- except as expressly provided for under this License. Any other
- attempt to copy, modify, sublicense or distribute the Document is
- void, and will automatically terminate your rights under this
- License. However, parties who have received copies, or rights,
- from you under this License will not have their licenses
- terminated so long as such parties remain in full compliance.
-
- 10. FUTURE REVISIONS OF THIS LICENSE
-
- The Free Software Foundation may publish new, revised versions of
- the GNU Free Documentation License from time to time. Such new
- versions will be similar in spirit to the present version, but may
- differ in detail to address new problems or concerns. See
- `http://www.gnu.org/copyleft/'.
-
- Each version of the License is given a distinguishing version
- number. If the Document specifies that a particular numbered
- version of this License "or any later version" applies to it, you
- have the option of following the terms and conditions either of
- that specified version or of any later version that has been
- published (not as a draft) by the Free Software Foundation. If
- the Document does not specify a version number of this License,
- you may choose any version ever published (not as a draft) by the
- Free Software Foundation.
-
-E.1.1 ADDENDUM: How to use this License for your documents
-----------------------------------------------------------
-
-To use this License in a document you have written, include a copy of
-the License in the document and put the following copyright and license
-notices just after the title page:
-
- Copyright (C) YEAR YOUR NAME.
- Permission is granted to copy, distribute and/or modify this document
- under the terms of the GNU Free Documentation License, Version 1.2
- or any later version published by the Free Software Foundation;
- with no Invariant Sections, no Front-Cover Texts, and no Back-Cover
- Texts. A copy of the license is included in the section entitled ``GNU
- Free Documentation License''.
-
- If you have Invariant Sections, Front-Cover Texts and Back-Cover
-Texts, replace the "with...Texts." line with this:
-
- with the Invariant Sections being LIST THEIR TITLES, with
- the Front-Cover Texts being LIST, and with the Back-Cover Texts
- being LIST.
-
- If you have Invariant Sections without Cover Texts, or some other
-combination of the three, merge those two alternatives to suit the
-situation.
-
- If your document contains nontrivial examples of program code, we
-recommend releasing these examples in parallel under your choice of
-free software license, such as the GNU General Public License, to
-permit their use in free software.
-
-Index
-*****
-
-blocklist: See 13.3.1. (line 2252)
-boot: See 13.3.2. (line 2259)
-bootp: See 13.2.1. (line 1862)
-cat: See 13.3.3. (line 2267)
-chainloader: See 13.3.4. (line 2276)
-cmp: See 13.3.5. (line 2288)
-color: See 13.2.2. (line 1874)
-configfile: See 13.3.6. (line 2304)
-current_drive: See D.3. (line 3498)
-current_partition: See D.3. (line 3502)
-current_slice: See D.3. (line 3505)
-debug: See 13.3.7. (line 2310)
-default: See 13.1.1. (line 1810)
-device: See 13.2.3. (line 1935)
-devread: See D.3. (line 3550)
-dhcp: See 13.2.4. (line 1950)
-disk_read_func: See D.3. (line 3541)
-displayapm: See 13.3.8. (line 2319)
-displaymem: See 13.3.9. (line 2325)
-embed: See 13.3.10. (line 2338)
-fallback: See 13.1.2. (line 1822)
-FDL, GNU Free Documentation License: See E.1. (line 3716)
-filemax: See D.3. (line 3538)
-filepos: See D.3. (line 3531)
-find: See 13.3.11. (line 2352)
-fstest: See 13.3.12. (line 2361)
-FSYS_BUF: See D.3. (line 3525)
-geometry: See 13.3.13. (line 2374)
-grub_read: See D.3. (line 3554)
-halt: See 13.3.14. (line 2385)
-help: See 13.3.15. (line 2393)
-hiddenmenu: See 13.1.3. (line 1833)
-hide: See 13.2.5. (line 1963)
-ifconfig: See 13.2.6. (line 1973)
-impsprobe: See 13.3.16. (line 2406)
-initrd: See 13.3.17. (line 2415)
-install: See 13.3.18. (line 2425)
-ioprobe: See 13.3.19. (line 2483)
-kernel: See 13.3.20. (line 2491)
-lock: See 13.3.21. (line 2513)
-makeactive: See 13.3.22. (line 2530)
-map: See 13.3.23. (line 2537)
-md5crypt: See 13.3.24. (line 2551)
-module: See 13.3.25. (line 2559)
-modulenounzip: See 13.3.26. (line 2570)
-pager: See 13.2.7. (line 1983)
-part_length: See D.3. (line 3517)
-part_start: See D.3. (line 3514)
-partnew: See 13.2.8. (line 1991)
-parttype: See 13.2.9. (line 2000)
-password: See 13.2.10. (line 2008)
-pause: See 13.3.27. (line 2577)
-print_a_completion: See D.3. (line 3558)
-print_possibilities: See D.3. (line 3520)
-quit: See 13.3.28. (line 2586)
-rarp: See 13.2.11. (line 2023)
-read: See 13.3.30. (line 2599)
-reboot: See 13.3.29. (line 2593)
-root: See 13.3.31. (line 2606)
-rootnoverify: See 13.3.32. (line 2623)
-saved_drive: See D.3. (line 3508)
-saved_partition: See D.3. (line 3511)
-savedefault: See 13.3.33. (line 2633)
-serial: See 13.2.12. (line 2033)
-setkey: See 13.2.13. (line 2055)
-setup: See 13.3.34. (line 2665)
-terminal: See 13.2.14. (line 2180)
-terminfo: See 13.2.15. (line 2212)
-testload: See 13.3.35. (line 2685)
-testvbe: See 13.3.36. (line 2697)
-tftpserver: See 13.2.16. (line 2225)
-timeout: See 13.1.4. (line 1843)
-title: See 13.1.5. (line 1850)
-unhide: See 13.2.17. (line 2237)
-uppermem: See 13.3.37. (line 2705)
-vbeprobe: See 13.3.38. (line 2717)