*20 MAINDEC-08-D1L0 BASIC PDP-8 MEMORY CHECKERBOARD BASIC PDP-8I MEMORY CHECKERBOARD STARTING ADDRESS LOC. 0005 LOW END CHECKERBOARD LOC. 7430 HIGH END CHECKERBOARD SWITCH SETTINGS SR 0100 STANDARD PDP-8 CORE SR 0101 STANDARD PDP-8I CORE ALSO SR 0000 AND SR 0001 ARE FOR SPECIAL CORE UNITS