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PalMA – share a team monitor

Copyright (C) 2014–2021 Universitätsbibliothek Mannheim

Authors: Alexander Wagner, Stefan Weil, Jörg Mechnich, Dennis Müller (UB Mannheim)

This is free software. You may use it under the terms of the GNU General Public License (GPL). See docs/gpl.txt for details.

Parts of the software use different licenses which are listed in file LICENSE.

Build Status Codacy Badge Scrutinizer Code Quality


PalMA enables people to share several contents on one monitor. Users can display PDF files, office files, images, videos, websites and or computer screens in real time (up to four entries simultaneously). Everything can be controlled via a website, so it's perfectly usable for all kinds of (mobile) devices.

PalMA in Use

PalMA in use




See for details.

Mannheim University Library develops and installs PalMA on mini PCs running the stable releases of Debian GNU Linux and Raspbian. Other Linux based hardware and software combination can also be used, but might require some smaller modifications.

Hardware requirements

The team monitor (with adequate size and resolution) is connected to a computing device (usually a mini pc) running Linux. Hardware requirements for the pc are relatively low. For reasonable performance we recommend something at least as strong as a Raspberry Pi 3.

A minimal setup can be built with an ARM based mini pc like the Raspberry Pi for less than 100 EUR. It can drive monitors with HDMI and full HD resolution (1920 x 1080 pixel), but is slow and only offers limited memory for viewer applications.

A setup with good performance can be built with an Intel NUC for around 200 EUR. It also provides HDMI and resolutions up to 1920 x 1200 pixel.

A high end setup uses a mini pc with Intel Core i5, more RAM and a fast solid state disk (SSD). HDMI allows full HD resolution, display port (DP) even larger resolution.

Client Software

Microsoft Windows and Mac OS X clients need additional software if users want to share their desktop. These products were tested successfully with desktop computers and notebooks:

  • UltraVNC – (GNU General Public License) This is a free VNC server for Windows. Using the Single Click version UltraVNC SC, it is possible to address preconfigured displays without any installation.

  • VineServer – (GNU General Public License) This VNC server is needed for MacBooks with retina display.

  • x11vnc – (free) This VNC server is included in most Linux distributions.

It is currently not possible to share the desktop of mobile devices (smartphones / tablets).

Bug reports

Please file your bug reports to Make sure that you are using the latest version of the software before sending a report.


Bug fixes, new functions, suggestions for new features and other user feedback are much appreciated.

The source code is available from Please prepare your code contributions also on GitHub.


This project uses other free software: