Halcyon Calc

This is truly one of the best. Faithful reproduction of the HP-28S, the first user RPL calculator, that keeps all the good stuff and improves on the not-so-good (the display, for example, is so much better than that on the actual calculator). Stable and well thought out, with a very polished look. The plotting capabilities are pretty amazing. Very responsive developer; helped me immediately with a workaround to a minor problem and released an update within a few days. Allows me to do anything I used to do with my old 28S, and without the creaking plastic clamshell case sound! Highly recommended and worth every penny of the price. Hope to see more from this developer.

Love how responsive Halcyon Software is to fixing and improving this software. My favorite change on this release is the long or 3D press to get the red shift key. My 28S still runs perfectly but the battery door is so fragile. I can use Halcyon Calc all the time.

My HP 28S calculator (the best programmable scientific calculator ever built) is back! Thanks so much! I took a rather complicated engineering program from my 28 (which used some rather esoteric functions), laid it in, and it ran perfectly! Two thumbs WAY up! More if I had them.