The learning platform is a web-based application mainly written in Java. The following standard applications are supported:

  • Web server: Apache
  • Application server: Tomcat
  • Management of data: PostgreSQL, XML

To use this learning platform, you need an internet connection and a web browser (Google Chrome, Mozilla Firefox, Internet Explorer, etc.).



Recommendation for 300 concurrent users:

  • 8 GB RAM
  • 2 CPUs > 2 GHz
  • 200 GB HDD


We recommend Linux (64bit).

The following distributions are currently used for productive instances:

  • Scientific Linux
  • Red Hat Enterprise Linux
  • Ubuntu
  • Open Suse
  • SUSE Linux Enterprise Server 

Other distributions are possible.

Software components

  • Web server: Apache web server + mod_ssl (mod_jk or proxy_ajp)
  • Database server: Postgresql
  • Application server: Java 17, Apache Tomcat 9


  • Up to 300 concurrent users: All components on one server
  • Up to 500 concurrent users: Separation between database server and application server
  • Up to 800 concurrent users: Separation between database server, application server, and web server
  • Up to 1200 concurrent users: Multiple OPAL nodes on the application server
  • More than approx. 1500 concurrent users: Multiple application servers
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