Blinkenlight front panels for everybody!

Connecting a real Blinkenlight front panel to SimH is extremely cool, but has one drawback: Only the panel-owning guy (that's me!) has the full fun, all others have to watch some videos.

So the second-cool thing would be a realistic software simulation of a given Blinkenlight panel, which can be distributed to everyone.

blinkenbone real-pdp11-40,panelsim-1

Above you can see the simulated panel running on a PC monitor, below there is the real PDP-11/40 panel.

Download from and run a complete SimH & panelsim distribution

For all supported vintage computers, I packed together SimH, disk images with operating systems, PDF docs, the Java panel and startup scripts into one runnable "distribution".

A distribution is just a big .zip or .tgz with a startup script. Download from GitHub.

The is one distribution for every platform, one distribution contains all simulated machines.

Docs for every machine and hints how to have to fun are given here.

Installation: How to run under Windows (Win32):

  1. You should be logged in with Administrator rights
  2. Download the archive file "" from GitHub.
  3. Unzip in a directory of your choice.
  4. Execute one of the start-up scripts: "pdp1140.bat", "pdp8i.bat" and so on. SimH and panelsim are started in parallel and communicate.
  5. If starting the first time, the Windows Firewall will panic and asks you to allow the network communication between client and server. It will ask for three (3) programs.
  6. Enjoy!

This should work from Windows XP to Windows 10.

Installation: How to run under Ubuntu 14 32/64bit

The distributions for desktop Linux were developed under Ubuntu, but the stuff should run on other Linuxes too. Starting from Ubunntu 13, the  x64 releases do not run 32 bit software by default anymore. So i had to add a distribution for Ubunto-x86 too.

  1. SimH is compiled with network support. So make sure you installed "libpcap" before installation, as described in the SimH compilation readme.
  2. Download one of the archive files "panelsim_ubuntu-x*.tgz"
  3. Unzip in a directory of your choice.
  4. Use this command: "tar -xvf panelsim_ubuntu.tgz -z "
  5. Execute the "" script: "sudo"
  6. Enjoy!

This does not seem to work with all Linux distributions: I was unhappy with an older Suse 10.

Installation: Running on Raspberry Pi Raspbian

There is also a distribution for the RaspberryPi under Raspbian. The RPi2 is almost powerful enough to update even big Java panels as fast as required. You can use a HDMI monitor or plug-on one of those "touch screen" displays.

Isntallation is the same as for desktop Ubuntu, but there are some specials:

  • Don't use a slow low-price SDcard, choose at least "Class 10".
  • Startup time for the Java panel can be very long (> 10 seconds on RPi 2). This may time out the "ping" period in the startup scripts, just increase the limit.
  • The version of Raspbian seems critical: on V 3.18, I found it necessary to restart the "rpcbind" with option -i:
    ps -e |grep rpcbind
    sudo kill ....
    rpcbind -i
  • On v4.1 this is not necessary, and the Java seems to run much faster.


The Java PANELSIM program

Some facts:

  • The panel simulation program is written in Java, so it can run on any platform. This is important, since "Panelsim" should be able to follow SimH where ever it runs.
  • In the architecture overview, you see that the BeagleBone, which controls the real panel, acts as "Blinkenlight API server". The software simulation implements the same interface, so for Blinkenlight API clients like SimH there's no difference whether they control a real or a simulated panel.
  • You operate a switch by clicking onto it. On the PDP-11/40 LOAD ADRS, EXAM, DEP, START and CONT are "momentary action switches", they are only active as long you press the mouse button. All other switches are bi-stable.
  • All the lights and switches are individual photos of a real panel. so there's a big repository of images needed.
  • Image are provided in several fixed sizes, suitable to standard monitor resolutions: 800, 100, 1200, ...
  • A "selftest" button performs a lamp test ... and tests also all the switches ...
  • The "actvity" LED goes ON, if a client (SimH) is accessing the panelsim for switch reading or LED setting.
  • The display is updated only 20 times a second. So there's no much CPU power needed, even a 8 years old 1.4 GHz Notebook is sufficient. SimH itself is eating much more CPU cycles.


pdp10 ki10 virtual small