A Second GIGATRON can be your homebrew VGA output. MONITOR and. DE-BUG

[RJSV]

Hello !
   For closely following (potentially messy) machine code there is nothing like a simple panel. Of course the micro-code test / run-stop, and various direct memory reads and writes. The ability to write, to low level memory is actually hazardous, random bad luck, and Murphy's law : but the example use could be for running alongside another VGA driving GIGATRON.
Best thing is your normal running device can just, for example, play the fast scrolling racer video games, on usual GIGATRON.

In a speculative mode: Nice to have, maybe 4 logic sensing and high impedance mini-clips for inputs to the bench development monitor driver (so you would simply have TWO wooden cases.
So, the panel idea is old, from pre-IBM days, I imagine..
   In a 4 by 4 array, 0 - hexcode 15 can be entered.
   Button Functions:
      RUN.  HALT.  RDM. WRM.    ( 2 buttons for memory)
      BRK.   STEP.  RDIN. WROUT
        4.          5.        6.         7
        0.          1.         2.        3

       It can be loaded up with additional features, alarm timer, etc.