Installing multiple OS' to an external HDD

Older BIOS or newer UEFI system?

I have multiple installs of Ubuntu on two drives. My older BIOS system had so many old Ubuntu installs, many obsolete as I kept adding 25GB for a new / (root) partition for testing something. I had to tu off os-prober so it would not find the old installs and clog up the grub menu.

I prefer smaller system partitions and large data partition. Last system installed with BIOS will be the grub in MBR that controls booting, so system you expect to use the most should be last to install.
Use gparted to create all partitions in advance, but keep track. Installer does not show labels and I once installed to a new large data partition instead of my plaed / partition.

Lots of detail, screenshots and essential info.14.04 Something Else example
http://www.dedoimedo.com/computers/u...all-guide.html
http://askubuntu.com/questions/34326...g-installation
http://askubuntu.com/questions/16396...-windows-using
Any install with Something Else which is required with exteal drives or any second drive or any install with separate /home
Also shows combo box with location of grub2 boot loader
https://help.ubuntu.com/community/Grub2/Installing
Does not hightlight changing boot loader to sdb, if exteal drive, but shows other install screenshots:
http://askubuntu.com/questions/31278...in-a-dual-boot
http://askubuntu.com/questions/27437...p-boot-optiond
Install 14.04 Something Else explanation and screenshots (note boot load to VM, most may install to MBR of drive sda, or sdb)
http://www.tecmint.com/ubuntu-14-04-installation-guide/
And you want this screen to choose where to install the grub2 boot loader which is only available with Something Else or manual install
https://help.ubuntu.com/community/Gr...ing_Else.22.29:

I do not know Kali, but someone posted that it is not really intended to be installed, but just run as live install.