Open Source


A software or more precisely its program code is considered ‘Open Source’ if the software

  • may be freely copied, distributed and used, including commercial use.
  • may be modified and passed on in its modified form.
  • license fulfills the Open Source requirements.

‘Open Source’ is the technical term for open software in the sense of freely modifiable and usable software. The source code may not only be analyzed but also manipulated. The modified code is considered Open Source as well and can therefore be used by third parties as well. Note that Open Source software is not Freeware and not Shareware.


1969 AT&T develops the first version of UNIX but it is not used commercially. For a small fee universities are allowed to use UNIX. Over time a community is forming which is writing freely available software fore UNIX.

1984 AT&T is using UNIX commercially. From now on the source code is not open any more and developers are not allowed to work on free UNIX projects. Richard Stallman founds the GNU project. The goal is to build a UNIX-like system based entirely on free software.

1991 Linus Torvalds develops the free operating system Linux. He calls for all developers to use his code arbitrarily and to write Open Source software for Linux.

1998 Netscape publishes the source code of its Navigator. As an offspring several Open Source projects are initiated including the Mozilla project. In April of that year several well-known IT experts announce to support the term ‘Open Source’ instead of free software. This draws the media s attention to the Open Source community.

Today there are many Open Source projects. In particular in the Linux/UNIX arena substantial amounts of software are Open Source.

Open Source License

Such a license has to follow the directives of the Open Source Initiative. These directives, the so-called Open Source Definition (OSD), are not identical with the GPL (GNU General Public License) for free software. The OSD covers the following items:

  • Free distribution
    The license may not ask for any fees and may not prohibit commercial use.
  • Source code
    The software must be readable in its source code in a non-obstructive form.
  • Deduced work
    Modified Open Source software must apply the same license as was used in the software package it is based on.
  • Integrity of the author�s source code
    The license must explicitly allow the distribution of modified software but may ask for logging of new versions and names.
  • No discrimination of people or groups
    Specific people or groups may not be excluded from using Open Source software to maximize the effect of Open Source development.
  • No restriction for specific applications
    The license must allow using the software for any purpose, e.g. also for genetic sciences.
  • Licensing
    The license must be applicable to all users of the software without disabling the license indirectly by additional licenses.
  • Not product specific
    The license must not be specific to a particular product or distribution.
    The license may not interfere with any other software
  • Not technology specific
    The license may not bind the software to specific hardware platforms or technologies.