Persistent live Ubuntu in the USB flash drive
An easy solution is a persistent live installation on the USB flash drive. You can do that with mkusb. If you boot live (live-only) with the boot option
toram, you can install to the same drive as you booted from. See these links,
Installed Ubuntu in the USB flash drive
But if you want an installed system (installed in the same way as installed into an internal drive), and Windows is installed in UEFI mode, you must disconnect the internal drive. Otherwise the Ubuntu installer will install the grub bootloader into the EFI partition in the internal drive.
You find more details at the following link and links from it.
Try Ubuntu (Kubuntu, Lubuntu, Xubuntu, ...) before installing it
A persistent live system is more portable, but less stable, more sensitive to corrupting the file system. So it is important to backup the content of the
casper-rw partition regularly.
- It is possible to update & upgrade most program packages, but not the linux kernel and not the kernel drivers. The version from the image of iso file will be used during boot (before the persistent content from the
casper-rw partition is overlaid).
- It is a bad idea to make a general update & upgrade. It can easily corrupt the file system, and even if it works, the system will be slow if a lot of the programs are running from the overlay.
- You should only install the program packages that you want, and when you need a new version of Ubuntu, install it from a new iso file. And of you can tweak the system and save data files.
An installed system is more stable, but less portable, not as portable as a [persistent] live system.
- Avoid proprietary drivers unless necessary, because they decrease the portability. (This is typically concerning drivers for the graphics chip or wifi chip).
- Also, and this may be important for you, an installed system can be completely updated & upgraded, just like a system in an internal drive.
- But all systems in external drives are very sensitive to corrupting the file system, so also installed systems should be backed up regularly.