For once I feel a little out of touch after I took a bit of a break from following the news to focus on studying, and suddenly everyone is talking about immutable distributions. What are they exactly? What are the benefits and the disadvantages of immutable systems?
My understanding is that most immutable distributions store the root filesystem in a read-only partition separate from userspace. If you want to install something that would modify this partition, it is applied temporarily until reboot. On reboot, the operating system attempts to resolve your changes, and if they break something it will reject them.
Each OS might implement immutability differently, but I believe that’s the general idea. macOS is another example of an immutable operating system, as of Big Sur.