Free42 is a re-implementation of the HP-42S calculator and the HP-82240 printer.
It is a complete rewrite, not using any HP code, and it does not require an
HP-42S ROM image.  Free42 is an Open Source project. The executables and source
code are released under the terms of the GNU General Public License, version 2.
All third-party code used in Free42 is either in the public domain, or licensed 
under terms compatible with GPLv2, or used with the authors' permission.