About
Free42 is a re-implementation of the HP-42S Scientific Programmable Calculator and HP-82240 Printer, written from scratch without HP code and without requiring an HP-42S ROM image. It is released as open source under the GNU General Public License, version 2. Although it includes enhancements beyond the original calculator, it remains fully compatible with the HP-42S in both its user interface and its ability to run HP-42S programs.
For Mac users, the Free42 Binary is available as Free42Mac.zip and requires macOS 10.15 (Catalina) or later. The site also offers Free42 for Android, iOS, Windows, and Linux, as well as skins, sample programs, and command-line tools for converting raw program files to text and back.
The site references documentation including the original HP-42S Owner's Manual, an alternative HP-42S/Free42 manual, and a programming examples book, and lists Free42 extensions such as time and date functions, BASE enhancements, and program import/export. The Mac download description itself does not detail further Mac-specific features.
What's new
All release notesHomebrew cask free42-binary 3.4.1 (sha256 no_check).