42S Programmable RPN Scientific Calculator 42S is a Windows Phone port of Thomas Okken’s excellent Free42, a complete reimplementation of the highly praised HP-42S RPN scientific calculator which was made by Hewlett-Packard from 1988 until 1995. Thomas’ original code was written from scratch, without using any HP code or using any ROM images, yet it is fully compatible with the HP-42S offered by Hewlett-Packard. This app brings Thomas’ original reimplementation of the HP-42S to the Windows Phone platform providing all the functionality of the original HP-42S including several hundred built-in functions, extensive programmability, and printer output emulation.
