A suite of Gnu Emacs editor modes to support working with the FriCAS computer algebra system. Note: Frimacs is the successor to my previous axiom-environment package, which is now deprecated.


An application for Apple macOS to allow communication with Hewlett-Packard RPL-based calculators using the Kermit file transfer protocol. Both USB and RS232 calculator ports are supported (where available) on the HP48S, HP48SX, HP48G, HP48GX, HP48G+, HP48GII, HP49G, HP49G+ and HP50G calculators.

The latest version of Hoppi, version 2, is available here:-

Previous releases can be downloaded from here.

See Eric Rechlin's excellent site for (a lot) more information on these calculators.

An HP48GX RAM Card Design

Design files for a 512KB RAM card for HP48GX calculators.

RPL Stuff

RPL is the native programming language of HP48/49/50-series calculators.

HP Tools

This is the collection of PC-based command-line compiler, assembler and linker utilities released by HP for working with low-level RPL code (so-called System RPL). I provide the original sources here for download (version 3.0.8, released in 2002 by HP) along with a patch-file showing my own modifications that allow the tools to be compiled on modern 64-bit Mac, FreeBSD and Linux operating systems. They also tidy up some of the formatting in the documentation so I can print it out and read it.

Note: I do not supply a patched version of the sources as this is specifically against the HP licence agreement, which can be found in the COPYING file in the distribution.

To apply the above patch to the contents of the HP tarfile, first untar it then cd into it and issue the command "patch -p1 <../hptools-pdo-20190426.patch".

RPL Tools

My own Gnu Emacs tools for working with RPL source code. This is work-in-progress.

RPL Fragments

My own RPL programs. Not much here yet.


A Common Lisp library for interfacing with the Grace 2D plotting program.

Author: Paul Onions

Created: 2022-05-14 Sat 17:37