In the vast and versatile world of Linux, the concept of a live environment allows users to run an entire operating system directly from a USB stick or CD without installing it on a computer's hard ...

EXE GNU/Linux is a lightweight Devuan variant with a vintage look, suitable for system rescue. Sporting the retro Trinity desktop, EXE includes maintenance tools and lightweight apps by default.

So you pop in a CD, boot into a rescue operating system, and you are provided with a variety of tools for probing that otherwise inaccessible disk. Such is the purpose of system-rescue Linuxes.