I'm looking for a bootloader that doesn't need its own partition. It should be functional after I remove all partitions on the hard drive or fill them with garbage. If I leave out one arbitrary partition, I should be able to boot the OS from it without reinstalling the bootloader.

Of course I first tried grub and lilo, but they both failed. I searched the web and found GAG. It can be installed in the "first track" of the hard disk rather than a partition. Indeed, I tested it and it worked as expected. However, I don't like its windows look and feel.

I would prefer to use a more standard bootloader, one that has been packaged or maintained in major Linux distributions, such as grub, lilo, syslinux. Is it possible to configure them or patch them for this task?

You could try Plop Bootmanager
it can install to MBR and boot both linux and windows and more
its also configurable too; and it can boot usb, usb-cdroms,etc even on computers without bios support
http://www.plop.at/en/bootmanager.html

theres also grub4dos (grub.exe) and supergrubdisk...

Have "Smart Boot Manager" on a floppy
http://linux.simple.be/tools/sbm

Or install to hard disk ( MBR )
http://sourceforge.net/projects/btmgr/

I have 30+ different Linux's installed,
and never used a boot partition.
# sbminst -d /dev/sda
gets the loader installed to MBR.
.....

Thanks for your replies.

It's not open source, and I don't even see binaries for Linux. I'd rather not use this software.

Yes, grub4dos looks promising. It still requires a file on a disk partition, but it scans all partitions so it will work as long as there is at least one available.

I don't understand how this this would help me. Maybe I didn't make it clear in the first post, but I would like the main bootloader that resides in MBR of the hard drive to survive without manual intervention. Using cdrom or floppy or usb stick to boot is a manual intervention.

Thanks, it works great. However, I looked at the bug tracker and found some serious issues that remain unfixed. I'm not going to install the bootloader on my desktop PC, I'm going to install it in a place which I only visit occasionally, so I'm looking for something that is known to be stable.

Well, I had a look at the ' bug tracker ' link, and I don't
see anything, that is caused by the boot manager.
The complaints have quite other reasons , AFAIK.

I have used SBM in MBR since 2004 , on all computers.
For now it's on four computers. Never had any issues.
Boots ATA, SATA, cdrom, DVD , Linux, Solaris, BSD's, Windows.
.....