A boot loader is, at first glance, a menu that displays a list of operating systems. Before a computer boots, the boot loader allows a selection to be made from all available operating systems on the computer. This allows the user to have their computer installed with, for example, both Windows and Linux. The user can quickly choose between the two when the computer is turned on.
Choosing the right boot loader depends on the operating system that will be installed on the computer. This review covers six popular boot loaders, and the features and downfalls of each.
What is a boot loader (in more depth)?
A boot loader is the first piece of software used when a computer is booting. When the power switch is turned on the computer’s BIOS runs a series of checks it loads from firmware. When finished, the BIOS attempts to start an operating system from the hard drive. When a boot loader is installed it starts instead of an operating system. An increasing number operating systems install a boot loader by default, even if they are the only operating system on the computer.
In order for the BIOS to load an OS it looks for instructions on the first sector of a hard drive. On the first sector of the hard drive resides the master boot record (MBR), and is where a boot loader is initialized. Depending on the boot loader, additional files may be stored and read from a partition on the hard drive. After this step the boot loader begins to start the operating system, and is not used again until the next boot. If the computer has only one operating system, the boot loader may not ask for user input. Because of this, many people do not realize they have a boot loader installed.
Moving Beyond One Operating System
This setup using the default boot loader of the installed OS works well and never need to be configured or interacted with, until a second OS is to be added to the computer. Once the requirement of loading more than one operating system exists, many boot loaders, including the one shipped with Windows 98, no longer work. This is where a third party boot loader must be chosen. This page will help with that decision by comparing six popular boot loaders: LILO, GRUB, XOSL, System Commander, Boot Magic, and NTLDR.
Comparison of the Boot Loaders
|LILO||GRUB||XOSL||System Commander 7 (V Communications)||Boot Magic 8 (PowerQuest)||NTLDR (Microsoft)|
|Disk Support >1024 cylinders||yes (after version 21.3)||yes||yes||yes||yes||yes|
|Dedicated Partition Required?||no||no||no||no||no||no|
|Install through this OS||Linux||Linux||DOS||DOS, Windows 9x/NT/2000/XP||Windows 9x/NT/2000/XP||DOS, Windows 9x/NT/2000/XP|
|OSes able to be booted||DOS, Windows 9x/NT/2000/XP, Linux, BSD||DOS, Windows 9x/NT/2000/XP, Linux, BSD, BEOS, SCO Unix, OS/2, Solaris||DOS, Windows 9x/NT/2000/XP, Linux, BSD, BEOS, Solaris, VxWorks||ALL||DOS, Windows 9x/NT/2000/XP, Linux, BEOS||DOS, Windows 9x/NT/2000/XP, (Linux using bootpart)|
|Boot Linux Kernel?||yes||yes||no||no||no||no|
|Contained in MBR?||no||no||no||no||no||no|
|Filesystem Requirement (not contained in MBR)||
|Number of images supported||16||24|
|Resolutions Supported||text||text||up to1600x1200||up to 1600×1200||640×480||text|
|PS/2 Mouse Support||no||no||yes||yes||yes||no|
|Licence||GPL (free)||GPL (free)||GPL (free)||59.95/69.95||69.95 (comes with Partition Magic)||Incuded with Windows NT/2000/XP|
|Website||Lilo Homepage||Grub Homepage||XOSL||System Commander 7||Partition Magic||NTLDR Hacking Guide|
LILO is short for LInux LOader. It is open source and has been around for a long time. Its strengths include strong support from the community, being able to load a wide variety of operating systems, being able to load the Linux kernel, and being free. LILO must be installed and configured from an environment that can run the LILO executable (normally Linux and BSD). Once installed, a config file exists on the hard drive that, when edited, will change the OSes that can be booted. After editing this file, the LILO command will need to be run to update the changes in the MBR. This is not required in GRUB. One nice feature of LILO is the ability to copy itself to a floppy, allowing normal bootup of the host PC if the normal MBR is accidentally overwritten. The LILO menu on bootup is text-only, and can be in the form of a menu or prompt. If nothing is displayed at the prompt, hit to display a list of booting options.
GRUB, short for GRand Unified Bootloader, is another open source boot loader. GRUB has been slowly taking over LILO’s place as the default boot loader shipped with many Linux distributions. This is because of several features GRUB has that LILO does not. The first being that GRUB can be configured from within itself. If configured wrong, the user is not stuck with a unbootable computer, as the configuration can be changed from within GRUB. GRUB, while being a text menu, also supports background images, giving it the ability to impress your friends. GRUB also supports virtually any operating system that will run on x86 architecture. The only downfall to GRUB is that it requires files on the hard drive, usually on a Linux (ext2) partition.
XOSL is short for Extended Operating System Loader, and again is open source under the GPL license. XOSL is different from LILO and GRUB because it is a graphical boot loader, supporting resolutions up to 1600×1200. Like GRUB it supports configuration from within itself, but XOSL has several limitations. The XOSL installation manual suggests installing from true DOS into a FAT12 or FAT16 partition. NTFS partitions are rumored to work, but installation would need to take place through a DOS boot disk with NTFS drivers, or through Windows itself. XOSL also cannot boot the Linux kernel, making LILO or GRUB a required install to boot Linux.
System Commander 7
System Commander 7 from V Communications is a great boot loader for all different operating systems, as long as one of them is Windows or Dos. System Commander supports installation in Fat, Fat32, and has the rare support of installation in a NTFS partition. Like XOSL it is graphical, supporting resolutions up to 1600×1200. System Commander is also the only boot loader to claim support every operating system created for x86 architecture. It is configured within itself, and supports automatic searching for installed operating systems. The only downfall to System Commander is its price is hard to justify next to the free boot loaders, 59.95 for the download or 69.95 for a shipped product.
Boot Magic is a boot loader that comes only with the purchase of Partition Magic software. It differs from the other boot loaders because it must be installed in a FAT or FAT32 partition from within Windows. Boot Magic is also configured from within Windows, a feature making easier initial setup, but a more difficult recovery if a problem occurs. It’s limited support requiring Windows and a FAT partition make boot magic a choice only for limited configurations.
NTLDR comes with versions of Windows based on the NT kernel, including 2000 and XP. Hidden by default and not well documented, NTLDR appears to be designed only to switch between Windows 9x and NT. It has been discovered that it is possible to boot older versions of DOS and even Linux by editing the boot.ini file on the Windows partition. This is a great option for users wanting the change the least amount of options when installing a second operating system on their computer.