Hi,
I have a laptop running Xubuntu linux in dual boot with win XP from the Grub bootloader. I also have a USB flash drive with a live install of Kubuntu on it and a USB hard drive with an old version of win XP and also ubuntu on it. Is is possible to get grub to detect the operating systems on these USB devices so that i can boot them?

Any help would be much apreciated.

Cheers.

It depends on your BIOS. If BIOS can boot from usb, Grub can afaik as well.

I dont' think Grub will auto-detect operating systems though, you should be able to just boot from USB with your BIOS like shpenat mentioned, but since Grub rebuilds itself whenever you make changes to it, I don't believe it will modify itself on the fly to give you a menu option for an OS that wasn't there the last time you modified the Grub config.

The simple way is to have usb boot first in bios and edit your grub menu.lst on usb to boot your linux boot on hda or sda. That way when usb is disconnected your hda should still boot okay.

Hi,
Thanks for the replies. Have discovered that my laptop doesnt seem to auto detect USB drives at boot. I have another computer that does and you are right Grub automatically sets up the operating systems that exist on these USB devices. There is an option in the laptop bios to detect removeable devices and i have enabled that as first boot proirity but still wont detect the USB devices. Does this imply that i need to upgrade the bios? If this is the case is there an easy way to do this. The laptop is asus and i have looked on the Asus support website but my bios version seems to be up to date. Is there anything else that i should set in the bios settings that i have overlooked in order to enable USB detection at boot?

Your help is much appreciated.

Cheers.

You can try using Plop Bootmanager to boot the USB-does the laptop have a floppy or cd drive?

In some Bios the USB device can only be booted with "Legacy USB support" enabled.

My experience on Grub booting from a USB device is as follow:-

(1) Grub cannot detect a USB device as it has no driver for it.

(2) It the Bios that does the trick by forcing a USB device as the first bootable disk. In such a case Grub sees it as the first disk (hd0)

(3) In the above case (2) all other USB devices are not detected by Grub. This means Grub can only boot "one" USB device and it must be arranged by the Bios as the first boot disk.

(4) Once booted Grub has access to a Linux kernel and all USB devices can be seen.

Hope the above is clear. These are only my obervation and after many trials and tests.

If you don't believe me get a card reader and insert a Compact flash, a memory stick and a SD card in it. Grub only see the first one detected. Remove the first one and Grub sees the second one. Grub can boot all of them but only one device at a time because that is how the Bios arranaged it.

To answer the OP with several USB devices the answer is to unplug them all except the one to be booted. That is the only way.