Nitpicking: If you look at the very early versions of the Unix manuals, before even /lib was invented, there was a notion that /bin was the "system" (section 1

Nitpicking: If you look at the very early versions of the Unix manuals, before even /lib was invented, there was a notion that /bin was the "system" (section 1) and /usr/bin was "user software" (section 6). This fell by the wayside when they ran out of disk space on / and started putting section 1 commands in /usr/bin. At some point the system/user distinction was abandoned and everything but the games got moved to section 1 of the manual. (Back in those early days /lib files used to be in /etc. So did /sbin. There's still a meaningful semantic difference between programs any user could run vs programs only useful to root.) On *BSD there is no initramfs equivalent and the / partition still serves its traditional role of the minimal startup environment. And /home never existed before Linux - it was always something like /usr/home as far as I can tell.