Category Archives: Open Source

HowTo: Installing Yosemite into VirtualBox

This post should give a quick overview and some background on how to install Mac OS X 10.10 Yosemite in VirtualBox 4.3.22.

VirtualBox is great because it is probably the only free and open source software based virtualization environment that support most common platforms (like GNU/Linux, Windows, and Macintosh) and where the virtual machines are portable in case you want to switch the host’s operating system.

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Email encryption

As more and more people want to encrypt their personal communication to preserve and to protect their privacy, this post should give a quick introduction and some useful hints regarding email encryption based on OpenPGP.

First of all: It may initially look like being quite complicated. The available guide will require some thorough reading. But in the end it is not that complex and absolutely worth the effort. As soon as one is familiar with the basic concepts and techniques it will be nothing more than locking/unlocking your front door. And probably you did not yet remove your door lock for reasons of simplicity?

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Automatically generating image galleries based on

As you might have noticed all image galleries of this blog are meanwhile based on the framework. is great because it is Free/Libre Software (MIT-licensed), simply does what it is supposed to do, and requires not yet another plugin for WordPress nor a database backend. It also supports mobile devices and its typical touch gestures. Furthermore it enables self-hosted galleries and does not require to rely on any cloud services where you might loose control on your data.

The only thing that I was missing was a straight forward way to automatically generate a gallery. Creating it by hand – as for example described in’s “Beginners Guide” – is time-consuming, cumbersome, and error-prone. So the overall idea was to create a ready-to-run gallery based on a given folder that contains just the image files by using a shell script.

In detail I wanted to have the following functionality:
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Böses WhatsApp

Ein Sturm der Empörung läuft gerade über sämtliche Gruppenchats bei WhatsApp. Egal ob Freunde, Kollegen oder Freizeitclub:

“… ab morgen bin ich raus, ich schmeiß dieses böse WhatsApp runter und bin nur noch über [dazu kommen wir noch] erreichbar!”

Aber was ist passiert? Facebook hat WhatsApp und seine 450 Millionen Nutzer für 19 Milliarden Dollar gekauft. Nun kommt die große Angst, dass Facebook eifrig Werbung schaltet und fleißig mitschneidet inkl. Direktzugriff für die NSA.

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Use of Open Source Software in Health Care Delivery – Results of a Qualitative Field Study

The article about my previous research has finally been published in the IMIA Yearbook 2013. It is meant to provide a practitioner’s perspective on the use of medical free/libre and open source software (FLOSS) in clinical routine. In this context I examined and presented the opinions and experiences of chief information officers (CIO) working at larger hospitals. The abstract reads like this:

Objectives: To assess and analyze the attitude of health IT executives towards the utilization of specialized medical Open Source software (OSS) in Germany’s and other European countries’ health care delivery.

Methods: After an initial literature review a field study was carried out based on semi-structured expert interviews. Eight German and 11 other European health IT executives were surveyed. The results were qualitatively analyzed using the grounded theory approach. Identified concepts were reviewed using SWOT analysis.

Results: In total, 13 strengths, 11 weaknesses, 3 opportunities, and 8 threats of the utilization of OSS in a clinical setting could be identified. Additionally, closely related aspects like general software procurement criteria, the overall attitude of health IT executives, users, and management towards OSS and its current and future use could as well be assessed.

Conclusions: Medical OSS is rarely used in health care delivery. In order to capitalize the unique advantages of OSS in a clinical setting, complex requirements need to be addressed. Short-comings of OSS describe an attractive breeding ground for new commercial offerings and services that need yet to be seen.

Schmuhl, H., Heinze, O., & Bergh, B. (2013). Use of Open Source Software in Health Care Delivery – Results of a Qualitative Field Study. Contribution of the EFMI LIFOSS Working Group. Yearbook of medical informatics, 8(1), 107–13.

The full text article available via: | PubMed | Schattauer

I am looking forward to your feedback!

Zu unserer Sicherheit

Es fehlen einem erst mal die Worte, nachdem man das ZDF Interview (YouTube, Tran­skript) von Bierdimpfl CSU-Politiker und “Innenminister” Hans-Peter Friedrich vom 12.07.2013 gesehen hat. Ihm scheint auch nicht ganz wohl bei der Sache zu sein. Trotzdem sollen an dieser Stelle – zu unserer Sicherheit – ein paar Informationen im Kontext des “Überwachungsskandals” zusammengetragen werden und wie wir uns selbst schützen können:

PRISM Logo, welches stark an ein Schallplattencover erinnern. Man könnte es auch “The Dark Side of the Earth” nennen.

Auch wenn das Überwachungsprogramm PRISM in aller Munde ist, ist es nur eines von vielen. Da wären noch Tempora, Fairview, Stormbrew, Blarney, Oakstar, … Eine kommentierte ausführliche Übersicht gibt es bei Heise Online hat ebenfalls eine Zusammenfassung.

Nach einem Bericht der Monterey Herald hat die U.S. Army in ihrem Netzwerk, also für sämtliche Mitarbeiter weltweit, den Zugriff auf die Webseiten des Guardians blockiert, nachdem dort die ersten Berichte zu PRISM veröffentlicht wurden. “Netzwerk-Hygiene” nennt sich das. (via Heise Online)

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Towards Open Collaborative Health Informatics – The Role of Free/Libre Open Source Principles

A general overview article about free/libre and open source software in the context of health care to which I strongly contributed as co-author has recently been published in the IMIA Yearbook 2011. The abstract reads like this:

Objectives: To analyze the contribution of Free/Libre Open Source Software in health care (FLOSS-HC) and to give perspectives for future developments.

Methods: The paper summarizes FLOSS-related trends in health care as anticipated by members of the IMIA Open Source Working Group. Data were obtained through literature review and personal experience and observations of the authors in the last two decades. A status quo is given by a frequency analysis of the database of, one of the world’s largest platforms dedicated to FLOSS-HC. The authors discuss current problems in the field of health care and finally give a prospective roadmap, a projection of the potential influences of FLOSS in health care.

Results: FLOSS-HC already exists for more than 2 decades. Several projects have shown that FLOSS may produce highly competitive alternatives to proprietary solutions that are at least equivalent in usability and have a better total cost of ownership ratio. The database currently lists 221 projects of diverse application types.

Conclusions: FLOSS principles hold a great potential for addressing several of the most critical problems in health care IT. The authors argue that an ecosystem perspective is relevant and that FLOSS principles are best suited to create health IT systems that are able to evolve over time as medical knowledge, technologies, insights, workflows etc. continuously change. All these factors that inherently influence the development of health IT systems are changing at an ever growing pace. Traditional models of software engineering are not able to follow these changes and provide up-to-date systems for an acceptable cost/value ratio. To allow FLOSS to positively influence Health IT in the future a “FLOSS-friendly” environment has to be provided. Policy makers should resolve uncertainties in the legal framework that disfavor FLOSS. Certification procedures should be specified in a way that they do not raise additional barriers for FLOSS.

Karopka, T., Schmuhl, H., Marcelo, A., Molin, J. D., & Wright, G. (2011). Towards Open Collaborative Health Informatics – The Role of Free/Libre Open Source Principles. Contribution of the IMIA Open Source Health Informatics Working Group. Yearbook of medical informatics, 6(1), 63–72.

The full text article available via: | PubMed | Schattauer

I am looking forward to your feedback!