The PDP-11 had a timesharing OS called RSTS/E which could give maybe 10 people a BASIC programming experience a little bit better than an Apple ][. If you were messing with 8-bit microcomputers in 1981 you might think a 16-bit future would look like the PDP-11 but the 1970 design was long in the tooth by 1980 -- like 8-bit micros it was limited to a 64kb logical address space. Virtual memory let it offer 64k environments to more users, but not let a user have a bigger environment.