I *think* the 3/50 had a VME bus. As I recall, it was basically a single VME board mounted inside of a pizzabox case.

On Tue, Mar 28, 2017 at 11:27 AM, Larry McVoy <lm@mcvoy.com> wrote:

On Tue, Mar 28, 2017 at 11:23:49AM -0400, Arthur Krewat wrote:
> Is the 3/50 that much different than a 3/280?

Different bus structure as I recall. The 3/50 were workstations,
the 3/280 was big rack mounted VME (?) based system, mostly used
as file servers.