>> Are there any mainstream distros (not things like OpenWRT) that have / as not-your-main-hard-disk though? Sort of. Some smaller Linux live CD / live USB di

>> Are there any mainstream distros (not things like OpenWRT) that have / as not-your-main-hard-disk though? Sort of. Some smaller Linux live CD / live USB distributions such as Damn Small Linux (DSL) (https://en.wikipedia.org/wiki/Damn_Small_Linux https://en.wikipedia.org/wiki/Damn_Small_Linux) and Puppy Linux (https://en.wikipedia.org/wiki/Puppy_Linux https://en.wikipedia.org/wiki/Puppy_Linux) had the option to load the entire distribution into memory (RAM disk) and run completely from memory. This allowed them to run very fast since the entire base filesystem was in RAM and also be ephemeral since the filesystem would disappear on reboot or power off. Your could still mount the computer's hard disk or other removable disks, but / was in RAM. Other larger Linux live CD / live USB distributions such as Knoppix (https://en.wikipedia.org/wiki/Knoppix https://en.wikipedia.org/wiki/Knoppix) would place a core portion of the system on a RAM disk and then read from the CD / USB to get other files as needed. Plan 9 (https://en.wikipedia.org/wiki/Plan_9_from_Bell_Labs https://en.wikipedia.org/wiki/Plan_9_from_Bell_Labs) is not a Linux distro, but a Unix successor that extended the "everything is a file" Unix idea even further to allow multiple computers to act as one using the 9P protocol. This means that you could "mount" server _programs_ running on other computers somewhere under / and use file-like operations to interact with them. Almost like a REST API, but with 9P instead of TCP and file-like I/O instead of HTTP GET, PUT, and POST.