I downloaded the pdvim (fake 286) emulator, and have run a couple of tiny
programs on it (programs that dont use dos at all).
It says in the help that even the unregistered version should have a working "ZD" command
which is to load a virtual dos from the real dos.
(type ZD then return then G then return and see a C> prompt)
I cant get that to work and i dont know why.