---
layout: page
title: PDP-11/20 Bootstrap Loader Demo
permalink: /devices/pdp11/machine/1120/bootstrap/
machines:
  - id: test1120
    type: pdp11
---

PDP-11/20 Bootstrap Loader Demo
-------------------------------

The machine below pre-loads the [Bootstrap Loader](/apps/pdp11/boot/bootstrap/) code into 16Kb of RAM:

	<ram id="ram" addr="0x0000" size="0x4000" file="/apps/pdp11/boot/bootstrap/BOOTSTRAP-16KB.json"/>

and then pre-attaches the [Absolute Loader](/apps/pdp11/tapes/absloader/) tape image to the PC11 Paper Tape Reader:

	<device id="pc11" type="pc11" baudReceive="9600" autoMount='{path:"/apps/pdp11/tapes/absloader/DEC-11-L2PC-PO.json"}' ...>...</device>

Click "Run" to load the [Absolute Loader](/apps/pdp11/tapes/absloader/).
When the [Bootstrap Loader](/apps/pdp11/boot/bootstrap/) is finished, it will HALT,
leaving the [Absolute Loader](/apps/pdp11/tapes/absloader/) ready to run immediately after the HALT.

You can then select another tape image in the Absolute Loader format, such as [BASIC (Single User)](/apps/pdp11/tapes/basic/),
click "Attach" and then "Run".

If you need to start over, select "Bootstrap Loader (16Kb)" from the list of tapes and click "Load" instead of
"Attach", re-installing the [Bootstrap Loader](/apps/pdp11/boot/bootstrap/) directly into RAM.

Alternatively, just press the "Reset" button.  The RAM component was recently updated to restore pre-loaded images whenever
the entire machine is reset.  You'll still need to manually re-attach the [Absolute Loader](/apps/pdp11/tapes/absloader/)
tape image, however.

{% include machine.html id="test1120" %}

This machine is also available with our built-in [Debugger](debugger/).