Attempted to clean up mapUnibus() and bus-related faults; how well or ill-advised these changes are remains to be seen

devices/pdp11/machine/1120/monitor/README.md

@@ -0,0 +1,19 @@
+---
+layout: page
+title: PDP-11/20 Boot Monitor 
+permalink: /devices/pdp11/machine/1120/monitor/
+machines:
+  - id: test1120
+    type: pdp11
+---
+
+PDP-11/20 Boot Monitor
+----------------------
+
+The machine below pre-loads the [PDP-11 Boot Monitor](/apps/pdp11/boot/monitor/) into RAM:
+
+	<ram id="ram" addr="0x0000" size="0xE000" file="/apps/pdp11/boot/monitor/PDPJSMON.json" load="0xC000" exec="0xC000"/>
+
+{% include machine.html id="test1120" %}
+
+This machine is also available with our built-in [Debugger](debugger/).