David G. Miller wrote:
The funny thing is that back in the earliest days of Unix, /usr is where user directories lived. When K&R ran out of room in / for programs, they looked to for a partition that had additional space available and it was /usr. Originally programs ended up in /usr/bin simply because there wasn't room for them in /bin; not for some usage reason.
Yes, I recall that the first Unix system I ran, version 5 on a pdp-11/23, had two (enormous) 10MB disks, one for the kernel and the other /usr .