I know there are many ways of booting and managing multiple OSes, but I have a very specific question.

Let’s say I have one OS on one drive and one on another. I don’t want to use the built in boot manager. I want it to normally boot from one OS, but I want to be able to insert a USB stick with a boot manager on it that I can use to select the second OS.

When a system boots it looks for a specific device to find the bootstrap code from. I’m not sure you could override that with a USB stick.

You could set-up the BIOS to boot from USB first though and if not found, move to the normal OS.

I’d like the USB to boot into some kind of boot manager to let me choose. Can you install a boot manger without an OS?

If you are really good you could install grub2 and its dependencies onto an USB stick and use that.

Alternatively just stick a linux distro on the USB as a third OS, the bootmanager with that will be all set up.

Can’t imagine why you’d want to do things in such a round about way. Take a look at virtualbox as maybe a better solution.

I haven’t done it, but I think most BIOSes allow you to boot from a USB, so you would set the boot order with USB first, then your default hard drive. If you accidentally left a non-bootable USB in the socket it would fail to boot until you removed it but no harm done.

Still trying to get around your IT Departments security policies eh?

Just install grub with a zero time out. Then when you want to enter the boot loader you can press esc enter the boot loader and choose your 2nd O/S.

Alternatively you will need to reconfigure your BIOS to boot usb first and HDD/SSD 2nd. Then when you boot normally with out magic usb stick the BIOS will look for the usb fail then go to the HDD/SSD.

Can you install a boot manger without an OS?

Yes you just have to make sure the boot manger is in the MBR.

Nah, not trying to get around anything, I just want to be able to use the same hardware as a work machine and a play machine in the evenings via a second HD. If I could get around installing a bootloader on the main hd then that’d be nice, that’s all. Plus I would like to keep part of the second HD free for work purposes.

Also the main disk is PGPed which can cause problems with bootloaders I seem to remember…

I can set the BIOS to boot from USB but I don’t want to boot the contents of the USB, just have a bootloader on it. Looks like a linux distro on the USB is the way to go thanks all.

The boot loader can still point to a second drive if you want.

Can’t you set the bios to ask you which hard drive to boot from?

Then you don’t need a USB at all.

Or does that not fit the nefarious plan somehow?

Sounds like what you need is the USB stick to have a grub on it with config such that it points to /dev/sda and /dev/sdb

So if you boot into a linux live CD.. connect the USB stick.. use the linux live CD to edit the grub on the USB stick to contain the right entries you should be away… after selecting boot from USB of course

cant see why that wouldn’t work.. though never come across it

Graham I don’t think so…? I’ll check now as I have to restart – my trackpad seems to have packed up.

Conqueror – so from Linux I can put ONLY grub on a USB and don’t have to worry about messing with an actual distro?

Also some BIOSes let you press a key at bootime to select a different boot device.

Try Escape or F12.

this guide is similar to what you are after…

http://www.porteus.org/tutorials/37-installing/71-install-grub-to-usb-drive.html

if you are making the grub usb on the same computer as you intend to use it.. you might want to disconnect the hard drives physically to give yourself no chance of a **** up (by overwriting the MBR on the hard drive) 😛

that way you only be dealing with the devices which are the Live CD and the USB stick and the HDs won’t be visible in this process…

Honestly sounds like the easiest way is to get a 2nd laptop. Know plenty who do that as the easy/sensible way to do it. Keep everything for work on a work machine and the rest on your own. Did you supply the hardware or did work? If work did then get your own play machine.

Fab, thanks folks 🙂

not used it but this should detect your os and boot it.

Home

never used it but i have used other live cds that detect os to recover and fix them etc
give linux recover or rescue a google

F’in trackpad has packed up now 🙁