A Pro350 was an F11, a Pro380 a T11 (I hope I remember
this correctly)
CPU.
The 380 had a J11, the 350 had an F11. I *believe* the 280 was
somewhere between an 11/73 and an 11/53, and the 350 was somewhat
like an 11/23.
I think you could also run RT-11 on them. Some big VAX
models
had Pro's as console processors/systems. RD5x disk drives on
the Pro's.
Correct.
If memory serves me right, you had P/OS (a menu-driven branch of the
RT11 system), and Venix, a somewhat Unix-like system. Given some
work, one should be able to get standard RT working on it.
--f