|OS family||OS/2, L4|
|Source model||Open source|
|Latest release||0.0.4.7 / August 26, 2011|
|License||Various open source licenses|
The osFree Project is an open source operating system based on the L4 microkernel, and is intended to be binary compatible with application software made for OS/2 version 4. After several false starts in the first decade of the millennium, the project finally gained some traction in 2008.
Users and fans of the OS/2 operating system had discussed the possibility of creating an open source workalike of OS/2 ever since IBM announced that it would not be supplying another client version of the OS in 1996. The name OS/3 was considered, but IBM held a trademark on that name. The trademark lapsed in 1996, but the project moved forward with the soundalike "osFree".
OS/2 OEM code release
The project's goal is to replace all of OS/2's closed source subsystems with open source equivalents. The OS/2 API lists the functions that the operating system can perform for software developed for the platform, so programmers can reproduce the functionality of each API call in the same way that the Wine team uses the Windows API to reproduce the functionality of Windows API calls.
Creating a stable kernel is difficult, so using an existing kernel as the basis for the operating system would eliminate a major element of the project's development. Two open source operating system projects, Voyager and ReactOS, were considered as the potential basis of osFree, but Voyager was ultimately vaporware. A poll was held in 2005, and ReactOS was the most popular option.
first versions booted in 2005  using the L4 kernel but at that time it was still a module replacement
Adaption of L4 kernel
that the choice of kernel was a mistake, and
specifically the L4 Linux variant
takeover in early 2009 of the freePM project 
will probably always be a bit
- USPTO Trademark 74157588
- "Voyager main page".
- OSNews: osFree Publishes First Screenshot 2005-11-24
- Quinnell, Richard A. "Microkernel and Modular OSs". EDN Magazine. Retrieved April 9, 2013.
Digital Equipment Corp and IBM are also in the running. The two have teamed to develop and promote an open microkernel based on the Mach technology.
- L4 mailing list: 16-bit code and L4 2007-06-20
- Sourceforge: freePM takeover announcement 2009-04-08 (Note: Originally referenced to freePM forums but that forum has been deleted)