best way to install Ubuntu on external hard drive?

[M. Fioretti]

Hello list,

A school I work for asked me to install Linux on an old rugged laptop
they bought on eBay (GETAC M230, never seen something so though. Could
last 30 more years). Problem is, I cannot change the boot sequence,
because I only have the "regular" BIOS password, but:

* the boot sequence can only be changed "by supervisor" and...

* I could find NO info online how to even try to switch to this BIOS
  supervisor mode. There is no such entry in the BIOS

* and then I should have the corresponding password, of course.

At this point, the only way I can think at the end of a long day to
get Ubuntu on that computer is to take off the drive, connect it to
another computer, and install from there. Something like this (for SUSE, but is a generic process)

https://www.suse.com/c/how-create-external-usb-bootable-linux-hard-drive-without-dual-boot/

I'd rather not mess like that with my own desktop. If nothing else
because I would need to read documentation during the install process
itself. So, how could I install Ubuntu on an external USB hard
drive... from a computer that is running Ubuntu on its own, while it
is running it?

TIA,
Marco

-- 

M. Fioretti http://mfioretti.com                   http://stop.zona-m.net

Your own civil rights and the quality of your life heavily depend on how
software is used *around* you