I would like to know the grub install location which is best and safe for a windows XP multi-boot system. I have 2 hard drives, 1 internal IDE, and 1 external eSATA drive. I have Linux installed on both drives, with several partitions on each disk. During a Linux install is it not correct to place the grub boot loader onto the windows drive MBR? Or should it be put on a separate boot partition where the Linux /root is? Also is it possible to put the grub onto the external drive when it is connected eSATA, and be able to boot both internal and external operating systems, or even install the grub onto a bootable USB flash drive?

If your usb or sata is seen in bios boot order yes you can place grub at either place to boot your distros. Grub requires very little space and I usually create a 200 meg partition on my first bootable drive and install grub there. What ever you use to boot load you will need to place it in mbr. I also use the indirect boot method or chain loading.

What file system can be used with a grub install, fat32, ext2 and 3, NTFS, or can a grub boot loader be installed on any file system? Does a external SATA hard drive with only Linux distro's installed on it, have a MBR, or is the master boot record only a windows thing? And are there not other files needed to be on an external removable type drive along with the GRUB, to make it bootable, ( such as ntldr, boot.ini, NTdetect )? My external HD is both eSATA and USB connection capable. I do have a bootable Linux pendrive USB flash drive, can I just put the grub onto that maybe?

Have you read the manual - it might help you answer your questions? http://www.gnu.org/software/grub/manual/grub.html

The easiest for me with trying various distros has been to let one distro overwrite the MBR (after creating a backup of the MBR to restore if I want to delete the distro and restore the Windows bootloader), then install each subsequent linux distro's bootloader to the same partition as that distro, and chainload it.

Those Windows files like ntldr that you mention stay in Windows - Windows is chainloaded.

there are 2 main options

1) bios to bootable xp partition with ntldr chainloads the grub image to boot linux if you want linux
2) bios to bootable grub partition either a separate or shared partition of linux which chainloads to xp bootloader if you want xp

check out my signature.

ps if you like grub....its often quicker to have a linux live cd handy....as if there is a prob with xp...xp recovery will wipe out grub but you can just re-install it with a few clicks of the keyboard.

good luck