On Sat, 24 Oct 2015, Cindy Croxton wrote:
How small is "really small"? IBM made a
terminal with a 5" screen for
the 4704 banking systems.
http://frente-cajas.blogspot.com/
And the Atari Portfolio runs a version of DR-DOS.
And the Poqet ran MS-DOS.
Both have serial ports available.
Both will run DOS software, including most of the undocumented calls, such
as TSRs.
Either can function as a terminal.