Map & Guide 7 serial key or number

Table of Contents

This is the documentation of GNU GRUB, the GRand Unified Bootloader, a flexible and powerful boot loader program for a wide range of architectures.

This edition documents version 2.04.

This manual is for GNU GRUB (version 2.04, 24 June 2019).

Copyright © 1999,2000,2001,2002,2004,2006,2008,2009,2010,2011,2012,2013 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.

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-loading¹. 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 (see Command-line interface), or a menu interface (see 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 (see 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 (see Naming convention) to GRUB, how to install GRUB on your drive (see Installation), and how to boot your OSes (see Booting), step by step.

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 (see Motivation in The Multiboot Specification), 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. See Obtaining and Building GRUB, for more information.

Over the next few years, GRUB was extended to meet many needs, but it quickly became clear that its design was not keeping up with the extensions being made to it, and we reached the point where it was very difficult to make any further changes without breaking existing features. Around 2002, Yoshinori K. Okuji started work on PUPA (Preliminary Universal Programming Architecture for GNU GRUB), aiming to rewrite the core of GRUB to make it cleaner, safer, more robust, and more powerful. PUPA was eventually renamed to GRUB 2, and the original version of GRUB was renamed to GRUB Legacy. Small amounts of maintenance continued to be done on GRUB Legacy, but the last release (0.97) was made in 2005 and at the time of writing it seems unlikely that there will be another.

By around 2007, GNU/Linux distributions started to use GRUB 2 to limited extents, and by the end of 2009 multiple major distributions were installing it by default.

1.3 Differences from previous versions

GRUB 2 is a rewrite of GRUB (see History), although it shares many characteristics with the previous version, now known as GRUB Legacy. Users of GRUB Legacy may need some guidance to find their way around this new version.

• The configuration file has a new name ( rather than or ), new syntax (see Configuration) and many new commands (see Commands). Configuration cannot be copied over directly, although most GRUB Legacy users should not find the syntax too surprising.
• is typically automatically generated by (see Simple configuration). This makes it easier to handle versioned kernel upgrades.
• Partition numbers in GRUB device names now start at 1, not 0 (see Naming convention).
• The configuration file is now written in something closer to a full scripting language: variables, conditionals, and loops are available.
• A small amount of persistent storage is available across reboots, using the and commands in GRUB and the utility. This is not available in all configurations (see Environment block).
• GRUB 2 has more reliable ways to find its own files and those of target kernels on multiple-disk systems, and has commands (see search) to find devices using file system labels or Universally Unique Identifiers (UUIDs).
• GRUB 2 is available for several other types of system in addition to the PC BIOS systems supported by GRUB Legacy: PC EFI, PC coreboot, PowerPC, SPARC, and MIPS Lemote Yeeloong are all supported.
• Many more file systems are supported, including but not limited to ext4, HFS+, and NTFS.
• GRUB 2 can read files directly from LVM and RAID devices.
• A graphical terminal and a graphical menu system are available.
• GRUB 2’s interface can be translated, including menu entry names.
• The image files (see Images) that make up GRUB have been reorganised; Stage 1, Stage 1.5, and Stage 2 are no more.
• GRUB 2 puts many facilities in dynamically loaded modules, allowing the core image to be smaller, and allowing the core image to be built in more flexible ways.

1.4 GRUB features

The primary requirement for GRUB is that it be compliant with the Multiboot Specification, which is described in Motivation in The Multiboot Specification.

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, NetBSD², 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 (see Commands) are a superset of those supported on the command-line. An example configuration file is provided in 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 (see Commands) are a subset of those supported for configuration files. Editing commands closely resembles the Bash command-line (see Command Line Editing in Bash Features), with -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 Amiga Fast FileSystem (AFFS), AtheOS fs, BeFS, BtrFS (including raid0, raid1, raid10, gzip and lzo), cpio (little- and big-endian bin, odc and newc variants), Linux ext2/ext3/ext4, DOS FAT12/FAT16/FAT32, exFAT, F2FS, HFS, HFS+, ISO9660 (including Joliet, Rock-ridge and multi-chunk files), JFS, Minix fs (versions 1, 2 and 3), nilfs2, NTFS (including compression), ReiserFS, ROMFS, Amiga Smart FileSystem (SFS), Squash4, tar, UDF, BSD UFS/UFS2, XFS, and ZFS (including lzjb, gzip, zle, mirror, stripe, raidz1/2/3 and encryption in AES-CCM and AES-GCM). See Filesystem, for more information.

Support automatic decompression

Can decompress files which were compressed by or ³. 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.⁴

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 (see Motivation in The Multiboot Specification), 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.

1.5 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”⁵ 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.

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:

First of all, GRUB requires that the device name be enclosed with ‘’ and ‘’. The ‘’ part means that it is a floppy disk. The number ‘’ is the drive number, which is counted from zero. This expression means that GRUB will use the whole floppy disk.

Here, ‘’ means it is a hard disk drive. The first integer ‘’ indicates the drive number, that is, the first hard disk, the string ‘’ indicates the partition scheme, while the second integer, ‘’, indicates the partition number (or the PC slice number in the BSD terminology). The partition numbers are counted from one, not from zero (as was the case in previous versions of GRUB). 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.

This specifies the first extended partition of the first hard disk drive. Note that the partition numbers for extended partitions are counted from ‘’, regardless of the actual number of primary partitions on your hard disk.

This means the BSD ‘’ partition on first PC slice number of the second hard disk.

Of course, to actually access the disks or partitions with GRUB, you need to use the device specification in a command, like ‘’ or ‘’. To help you find out which number specifies a partition you want, the GRUB command-line (see Command-line interface) options have argument completion. This means that, for example, you only need to type

followed by a , 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:

This specifies the file named ‘’, 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 OS-specific notes about grub tools

On OS which have device nodes similar to Unix-like OS GRUB tools use the OS name. E.g. for GNU/Linux:

On AROS we use another syntax. For volumes:

E.g.

For disks we use syntax:

E.g.

On Windows we use UNC path. For volumes it’s typically

E.g.

For disks it’s

E.g.

Beware that you may need to further escape the backslashes depending on your shell.

When compiled with cygwin support then cygwin drive names are automatically when needed. E.g.

4 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 (see 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) by using the utility (see Invoking grub-install) on a UNIX-like OS.

GRUB comes with boot images, which are normally put in the directory (for BIOS-based machines ). Hereafter, the directory where GRUB images are initially placed (normally ) will be called the image directory, and the directory where the boot loader needs to find them (usually ) will be called the boot directory.

4.1 Installing GRUB using grub-install

For information on where GRUB should be installed on PC BIOS platforms, see BIOS installation.

In order to install GRUB under a UNIX-like OS (such as GNU), invoke the program (see 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 has to be either a device file (like ‘’). For example, under Linux the following will install GRUB into the MBR of the first IDE disk:

Likewise, under GNU/Hurd, this has the same effect:

But all the above examples assume that GRUB should put images under the directory. If you want GRUB to put images under a directory other than , you need to specify the option . The typical usage is that you create a GRUB boot floppy with a filesystem. Here is an example:

Some BIOSes have a bug of exposing the first partition of a USB drive as a floppy instead of exposing the USB drive as a hard disk (they call it “USB-FDD” boot). In such cases, you need to install like this:

This install doesn’t conflict with standard install as long as they are in separate directories.

Note that is actually just a shell script and the real task is done by other tools such as . Therefore, you may run those commands directly to install GRUB, without using . 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.

On EFI systems for fixed disk install you have to mount EFI System Partition. If you mount it at then you don’t need any special arguments:

Otherwise you need to specify where your EFI System partition is mounted:

For removable installs you have to use and specify both and :

4.2 Making a GRUB bootable CD-ROM

GRUB supports the no emulation mode in the El Torito specification⁶. 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 image called , which is concatenated with . The used for this should be built with at least the ‘’ and ‘’ modules. Your bootable CD-ROM will usually also need to include a configuration file and some other GRUB modules.

To make a simple generic GRUB rescue CD, you can use the program (see Invoking grub-mkrescue):

You will often need to include other files in your image. To do this, first make a top directory for the bootable image, say, ‘’:

Make a directory for GRUB:

If desired, make the config file under (see Configuration), and copy any files and directories for the disc to the directory .

Finally, make the image:

This produces a file named , which then can be burned into a CD (or a DVD), or written to a USB mass storage device.

The root device will be set up appropriately on entering your configuration file, so you can refer to file names on the CD without needing to use an explicit device name. This makes it easier to produce rescue images that will work on both optical drives and USB mass storage devices.

4.3 The map between BIOS drives and OS devices

If the device map file exists, the GRUB utilities (, etc.) read it to map BIOS drives to OS devices. This file consists of lines like this:

is a drive specified in the GRUB syntax (see Device syntax), and is an OS file, which is normally a device file.

Historically, the device map file was used because GRUB device names had to be used in the configuration file, and they were derived from BIOS drive numbers. The map between BIOS drives and OS devices cannot always be guessed correctly: for example, GRUB will get the order wrong if you exchange the boot sequence between IDE and SCSI in your BIOS.

Unfortunately, even OS device names are not always stable. Modern versions of the Linux kernel may probe drives in a different order from boot to boot, and the prefix ( versus ) may change depending on the driver subsystem in use. As a result, the device map file required frequent editing on some systems.

GRUB avoids this problem nowadays by using UUIDs or file system labels when generating , and we advise that you do the same for any custom menu entries you write. If the device map file does not exist, then the GRUB utilities will assume a temporary device map on the fly. This is often good enough, particularly in the common case of single-disk systems.

However, the device map file is not entirely obsolete yet, and it is used for overriding when current environment is different from the one on boot. Most common case is if you use a partition or logical volume as a disk for virtual machine. You can put any comments in the file if needed, as the GRUB utilities assume that a line is just a comment if the first character is ‘’.

4.4 BIOS installation

MBR

The partition table format traditionally used on PC BIOS platforms is called the Master Boot Record (MBR) format; this is the format that allows up to four primary partitions and additional logical partitions. With this partition table format, there are two ways to install GRUB: it can be embedded in the area between the MBR and the first partition (called by various names, such as the "boot track", "MBR gap", or "embedding area", and which is usually at least 31 KiB), or the core image can be installed in a file system and a list of the blocks that make it up can be stored in the first sector of that partition.

Each of these has different problems. There is no way to reserve space in the embedding area with complete safety, and some proprietary software is known to use it to make it difficult for users to work around licensing restrictions; and systems are sometimes partitioned without leaving enough space before the first partition. On the other hand, installing to a filesystem means that GRUB is vulnerable to its blocks being moved around by filesystem features such as tail packing, or even by aggressive fsck implementations, so this approach is quite fragile; and this approach can only be used if the filesystem is on the same disk that the BIOS boots from, so that GRUB does not have to rely on guessing BIOS drive numbers.

The GRUB development team generally recommends embedding GRUB before the first partition, unless you have special requirements. You must ensure that the first partition starts at least 31 KiB (63 sectors) from the start of the disk; on modern disks, it is often a performance advantage to align partitions on larger boundaries anyway, so the first partition might start 1 MiB from the start of the disk.

GPT

Some newer systems use the GUID Partition Table (GPT) format. This was specified as part of the Extensible Firmware Interface (EFI), but it can also be used on BIOS platforms if system software supports it; for example, GRUB and GNU/Linux can be used in this configuration. With this format, it is possible to reserve a whole partition for GRUB, called the BIOS Boot Partition. GRUB can then be embedded into that partition without the risk of being overwritten by other software and without being contained in a filesystem which might move its blocks around.

When creating a BIOS Boot Partition on a GPT system, you should make sure that it is at least 31 KiB in size. (GPT-formatted disks are not usually particularly small, so we recommend that you make it larger than the bare minimum, such as 1 MiB, to allow plenty of room for growth.) You must also make sure that it has the proper partition type. Using GNU Parted, you can set this using a command such as the following:

If you are using gdisk, set the partition type to ‘’. With partitioning programs that require setting the GUID directly, it should be ‘’.

Caution: Be very careful which partition you select! When GRUB finds a BIOS Boot Partition during installation, it will automatically overwrite part of it. Make sure that the partition does not contain any other data.

5 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.

5.1 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.

5.1.1 How to boot an OS directly with GRUB

Multiboot (see Motivation in The Multiboot Specification) 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 (see Chain-loading).

FIXME: this section is incomplete.

1. Run the command (see boot).

However, DOS and Windows have some deficiencies, so you might have to use more complicated instructions. See DOS/Windows, for more information.

5.1.2 Chain-loading an OS

Operating systems that do not support Multiboot and do not have specific support in GRUB (specific support is available for Linux, FreeBSD, NetBSD and OpenBSD) must be chain-loaded, which involves loading another boot loader and jumping to it in real mode.

The command (see chainloader) is used to set this up. It is normally also necessary to load some GRUB modules and set the appropriate root device. Putting this together, we get something like this, for a Windows system on the first partition of the first hard disk:

On systems with multiple hard disks, an additional workaround may be required. See DOS/Windows.

Chain-loading is only supported on PC BIOS and EFI platforms.

5.2 Loopback booting

GRUB is able to read from an image (be it one of CD or HDD) stored on any of its accessible storages (refer to see loopback command). However the OS itself should be able to find its root. This usually involves running a userspace program running before the real root is discovered. This is achieved by GRUB loading a specially made small image and passing it as ramdisk to the kernel. This is achieved by commands , , , (see initrd), (see initrd), , or depending on the loader. Note that for knetbsd the image must be put inside miniroot.kmod and the whole miniroot.kmod has to be loaded. In kopenbsd payload this is disabled by default. Aditionally behaviour of initial ramdisk depends on command line options. Several distributors provide the image for this purpose or it’s integrated in their standard ramdisk and activated by special option. Consult your kernel and distribution manual for more details. Other loaders like appleloader, chainloader (BIOS, EFI, coreboot), freedos, ntldr and plan9 provide no possibility of loading initial ramdisk and as far as author is aware the payloads in question don’t support either initial ramdisk or discovering loopback boot in other way and as such not bootable this way. Please consider alternative boot methods like copying all files from the image to actual partition. Consult your OS documentation for more details

5.3 Some caveats on OS-specific issues

Here, we describe some caveats on several operating systems.

5.3.1 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. The command or similar may help you (see search).
2. Load the kernel and the modules, like this:
   grub> grub> grub>
3. Finally, run the command (see boot).

5.3.2 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. The command or similar may help you (see search).
2. Load the kernel using the command (see linux):
   grub>

   If you need to specify some kernel parameters, just append them to the command. For example, to set to ‘’, do this:

   grub>

   See the documentation in the Linux source tree for complete information on the available options.

   With GRUB uses 32-bit protocol. Some BIOS services like APM or EDD aren’t available with this protocol. In this case you need to use

   grub>
3. If you use an initrd, execute the command (see initrd) after :

   If you used you need to use :

   grub>
4. Finally, run the command (see boot).

Caution: If you use an initrd and specify the ‘’ 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 before loading the kernel. See uppermem, for more information.

5.3.3 NetBSD

Booting a NetBSD kernel from GRUB is also relatively easy: first set GRUB’s root device, then load the kernel and the modules, and finally run .

1. Set GRUB’s root device to the partition holding the NetBSD root file system. For a disk with a NetBSD disk label, this is usually the first partition (a:). In that case, and assuming that the partition is on the first hard disk, set GRUB’s root device as follows:
   grub> grub>

   For a disk with a GUID Partition Table (GPT), and assuming that the NetBSD root partition is the third GPT partition, do this:

   grub> grub>
2. Load the kernel using the command :

   Various options may be given to . These options are, for the most part, the same as in the NetBSD boot loader. For instance, to boot the system in single-user mode and with verbose messages, do this:

   grub>
3. If needed, load kernel modules with the command . A typical example is the module for the root file system:
   grub>
4. Finally, run the command (see boot).

5.3.4 DOS/Windows

GRUB cannot boot DOS or Windows directly, so you must chain-load them (see 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 (see drivemap), like this:

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 hides a DOS (or Windows) partition (see parttool), DOS (or Windows) will ignore the partition. If GRUB unhides a DOS (or Windows) partition, 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:

6 Writing your own configuration file

GRUB is configured using , usually located under . This file is quite flexible, but most users will not need to write the whole thing by hand.

6.1 Simple configuration handling

The program (see Invoking grub-mkconfig) generates files suitable for most cases. It is suitable for use when upgrading a distribution, and will discover available kernels and attempt to generate menu entries for them.

does have some limitations. While adding extra custom menu entries to the end of the list can be done by editing or creating , changing the order of menu entries or changing their titles may require making complex changes to shell scripts stored in . This may be improved in the future. In the meantime, those who feel that it would be easier to write directly are encouraged to do so (see Booting, and Shell-like scripting), and to disable any system provided by their distribution to automatically run .

The file controls the operation of . It is sourced by a shell script, and so must be valid POSIX shell input; normally, it will just be a sequence of ‘’ lines, but if the value contains spaces or other special characters then it must be quoted. For example:

Valid keys in are as follows:

‘’

The default menu entry. This may be a number, in which case it identifies the Nth entry in the generated menu counted from zero, or the title of a menu entry, or the special string ‘’. Using the id may be useful if you want to set a menu entry as the default even though there may be a variable number of entries before it.

For example, if you have:

menuentry 'Example GNU/Linux distribution' --class gnu-linux --id example-gnu-linux { ... }

then you can make this the default using:

GRUB_DEFAULT=example-gnu-linux

Previously it was documented the way to use entry title. While this still works it’s not recommended since titles often contain unstable device names and may be translated

If you set this to ‘’, then the default menu entry will be that saved by ‘’ or . This relies on the environment block, which may not be available in all situations (see Environment block).

The default is ‘’.

‘’

If this option is set to ‘’, then, when an entry is selected, save it as a new default entry for use by future runs of GRUB. This is only useful if ‘’; it is a separate option because ‘’ is useful without this option, in conjunction with . Unset by default. This option relies on the environment block, which may not be available in all situations (see Environment block).

‘’

Boot the default entry this many seconds after the menu is displayed, unless a key is pressed. The default is ‘’. Set to ‘’ to boot immediately without displaying the menu, or to ‘’ to wait indefinitely.

If ‘’ is set to ‘’ or ‘’, the timeout is instead counted before the menu is displayed.

‘’

If this option is unset or set to ‘’, then GRUB will display the menu and then wait for the timeout set by ‘’ to expire before booting the default entry. Pressing a key interrupts the timeout.

If this option is set to ‘’ or ‘’, then, before displaying the menu, GRUB will wait for the timeout set by ‘’ to expire. If is pressed during that time, it will display the menu and wait for input. If a hotkey associated with a menu entry is pressed, it will boot the associated menu entry immediately. If the timeout expires before either of these happens, it will boot the default entry. In the ‘’ case, it will show a one-line indication of the remaining time.

‘’

‘’

‘’

‘’

Variants of the corresponding variables without the ‘’ suffix, used to support vendor-specific power buttons. See Vendor power-on keys.

‘’

Set by distributors of GRUB to their identifying name. This is used to generate more informative menu entry titles.

‘’

Select the terminal input device. You may select multiple devices here, separated by spaces.

Valid terminal input names depend on the platform, but may include ‘’ (native platform console), ‘’ (serial terminal), ‘’ (serial terminal with explicit port selection), ‘’ (PC AT keyboard), or ‘’ (USB keyboard using the HID Boot Protocol, for cases where the firmware does not handle this).

The default is to use the platform’s native terminal input.

‘’

Select the terminal output device. You may select multiple devices here, separated by spaces.

Valid terminal output names depend on the platform, but may include ‘’ (native platform console), ‘’ (serial terminal), ‘’ (serial terminal with explicit port selection), ‘’ (graphics-mode output), ‘’ (VGA text output), ‘’ (MDA text output), ‘’ (Morse-coding using system beeper) or ‘’ (simple data protocol using system speaker).

‘’ is useful when no serial port is available. Connect the output of sending system (where GRUB is running) to line-in of receiving system (usually developer machine). On receiving system compile ‘’ from ‘’ and run:

parecord --channels=1 --rate=48000 --format=s16le | ./spkmodem-recv

The default is to use the platform’s native terminal output.

‘’

If this option is set, it overrides both ‘’ and ‘’ to the same value.

‘’

• EndNote X1 and later (paper box)- the product key is on a sticker on the back of the CD sleeve.
• EndNote X1 and later (plastic clamshell)- the sticker with the product key and serial number is on the case under the CD itself.
• EndNote X1 and later (download)- the product key, also known as the "Unlock code" is in the emailed order confirmation.

Serial Number: The serial number will be in the order confirmation email you received if you purchased the download version. For EndNote 9 and X, the serial number should be on the inside cover of the accompanying Getting Started Guide. For the EndNote 9 and X Upgrade versions, the serial number will be on the outside of the CD case. For older versions of EndNote, the EndNote serial number should be on the inside cover of the manual that the program came with.

If you are still unable to locate the serial number or product key, feel free to contact Account Services for further assistance. They should be able to search for your registration information in their database:

800-336-4474 (at the prompt press 3)
Email form

So you need to manually activate your Autodesk Software? Follow these steps to complete the manual activation process:

After you install your software, you can use it on a trial basis until you receive your Activation Code from Autodesk. 

To generate a request code to activate your software:

1. Disable your Internet connection and launch your software. This is an offline process. The screens below only appear if your computer is not connected to the Internet.
    
2. Click the Activate button on the Free Trial screen.
   
   Note: Autodesk software products operate on a Free Trial license until activated. If you purchased your software and didn't use it as a Free Trial, you still need to activate your software from the Free Trial screen.
    
3. Enter your Serial Number and Product Key. Click Next.
4. Select Request an activation code using an offline method. Click Next.
   
   

    

5. Record the activation information provided.
   
   **You'll need your product name, serial number, product key, and request code when you submit your request for an activation code on another computer.

   You can file an email request using the address provided or visit register.autodesk.com.

   
   The request code shown is for example only and will not work if used.  
   
   

6. Click Close to resume using your software in Free Trial mode while the request is being processed.

2. Request an Activation Code

To activate your software offline, complete an Activation Code request on a computer that does have Internet access. 

To get an Activation Code from AVA (Autodesk Virtual Agent):

1. Visit AVA (Autodesk Virtual Agent) for Activation help.

2. Fill out the product and registration information you recorded when you generated your request code.

3. Get your activation code instantaneously.

To get an Activation Code from online Product Registration & Activation:

1. Visit register.autodesk.com and sign in using your Autodesk Account information. If you don't have an Autodesk Account, follow the onscreen prompts to create one.
   
   Note: The Product Registration & Activation website requires an Autodesk ID to sign in and not your email address. If you don't know your Autodesk ID, sign in at accounts.autodesk.com using your email address and password to view your ID, which is listed under Profile/Security Settings.
    
2. Select your Operating System and enter your Serial Number. Click Next.
    
3. Select the product that matches the serial number you entered. Click Next.
    
4. Select an existing account or enter new account information. This is the name and address you wish to use for your software registration. Click Next.
    
5. Verify your registration information and enter your Request Code where prompted. Click Next.
   
   
6. Print or save your registration information, especially your Activation Code. You'll enter this information when you activate your software manually from the Free Trial screen.
   
   
    

3. Activate your Software Manually

After you receive your Activation Code, you can finish your software activation from the Free Trial screens.

To activate your software manually:

1. Disable your Internet connection, start the software, and click the Activate button on the Free Trial screen.

   Note: You will only see manual activation screens if you are using a computer that has no active Internet connection. 

   Autodesk software products operate on a Free Trial license until activated. If you purchased your software and didn't use it as a Free Trial, you still need to activate your software from the Free Trial screen.

2. Enter your Serial Number and Product Key. Click Next.

3. Select  I have an activation code from Autodesk and then enter the activation code in the spaces provided. Click Next to complete manual activation.

Note:  If you copy and paste the entire activation code into the first field, the remaining fields are automatically filled in.


 

Please Note:

Valid Serial Number Required: You'll need a valid serial number and matching product key. Before starting, be sure to find your serial number and matching product key.

We hope the information outlined above helps you get your Autodesk Software up-and-running but if you run into any issues, please do not hesitate to contact our Technical Support Team below!