Review of the Allschwil HP-Meeting on November 3rd:

It’s been two years since a group of HP pocket calculator enthusiasts last met in Allschwil and on 3 November 2018, 25 HP fanatics, users, inventors and nostalgics met again.

There was a new location for this year. The old location, a children’s primary school in Allschwil, complete with child-sized chairs and desks, had become too small, so a meeting complex attached to the Catholic Church in nearby Oberwil was chosen as the new venue.

The gates traditionally don’t open until 10am, however the first guests were early. By 10am, the majority of guests and speakers were present and busily catching-up over coffee and Swiss chocolate. The two years since the last meeting had clearly been eventful ones.

More or less punctually we started at 11am with the first presentation from first-time Allschwil attendee Hans Klaver. Hans presented „SOS, Stack Overflow Sensing for the HP-35“ in which described how an HP-35 could check for stack overflow. (Stack overflow is where the user runs out of stack levels when converting an algebraic expression into RPN. Experienced users do this conversion automatically and can track how many stack levels are in use, but novices can lose track. If this happens, hopefully an obviously wrong answered is returned and the user has merely wasted a little time. If the error is not spotted, however then the consequences are more significant.)
Hans took a web-based, HP-35 simulator written in JavaScript and modified it to track the stack levels in use and warn when an overflow occurs. A particularly neat touch is that he uses the famous red dot as an annunciator: pressing CLR clears the stack and illuminates the red dot, which stays on when all is well and extinguishes when stack overflow occurs.

It is well-known that Bernhard Emese loves a thrill. Instead of a standard PowerPoint presentation where nothing much can go wrong, the master of the soldering iron chose to carry out a live demonstration of installing his latest "Woodstock Low Power" kit into an HP-25. Clearly, you don’t need a presentation in perfect English to cast a spell over the audience who watched attentively as sockets and jumper wires were neatly unsoldered and re-soldered in front of us.
The "low power"‘ module is the latest in his line of repair kits for Woodstock models. This kit replaces the ACT chip, the memory, the two display drivers and the power supply. As long as the display and keyboard work, virtually all dead Woodstocks can now be repaired.
Small issues: such as wondering why the first attempt didn’t work and then realising that he had forgotten to include the display¬†were brilliantly improvised upon to give a very entertaining presentation.

Meindert Kuipers, a veteran of the Allschwil meetings, gave us a presentation on various HP-41 battery cases, all modified to take rechargeable lithium ion batteries. The battery is charged directly in the case from the HP-41’s normal power supply, with an included step-up booster to 5V (6V required if the card-reader is attached).

Angel Martin was next with a witty presentation about the way the HP-41’s library #4 was used over time by ROM vendors such as HEPAX and Zengrange to provide expansion memories and functions. Moving on to the HP-41CL (a replacement processor for the 41C produced by Systemyde) he described how commands were developed that take the library #4 paging technique to the limit, allowing any command from any of the 300+ ROMS built into the 41CL to be used.
Angel: your obsession with the 41 ROMs borders on crazy but that’s why I like you so much!

Lunch break was at 2.30 pm. There were hot Flammkuchen (pizza-type slices) and Schinkengipfel (sausage rolls) as well as dozens of interesting conversations. No doubt deals were struck by those who had bought items to sell. Afterwards we went outside into the courtyard for the obligatory group photo. Hans-Peter Bieger’s camera did the honours, clicking away madly under his remote control.


After more than an hour’s break, Sylvain Cote gave the first of his two presentations: a summary of the current state of the HP-41CL. Already two years ago he tried to show us how to update this magic machine - at that time still in several manual steps... In the last two years Sylvain has greatly simplified the procedure and offered us a variant to update the 41CL consisting of only four steps.
His second presentation was of his new Bible, the HP-IL Compendium. This is a huge project to bring together all of the HP-IL information into one place. Currently 180 pages in size, he expects it to increase to around 400 by the time it is complete. He hopes to produce monthly updates. We are intrigued by and, of course, very grateful for this extrememly detailed work.

Many participants were eagerly looking forward to the talk by Walter Bonin and Martin Lorang. (You may remember that Walter was one of the three main participants in the WP34 project to re-purpose the HP-20B / HP-30B calculators by flashing a completely new ROM.) Inspired by the success of the WP34, Walter is already working on the new major project, the WP43S, which is to port the WP34 software to run on Swiss Micros‘ DM42 hardware. With Martin on-board the project now has a competent programmer and is moving forward. He demonstrated the PC-based emulator which is fully functional and soon ready to be released to anyone who wishes to become a beta tester.
It was fantastic that Michael Steinmann from SwissMicros was present in the audience to clarify DM42 hardware questions and at the end of the presentation, an excited discussion broke out about which functions should be implemented.

Christoph Giesselink is a veritable prehistoric rock of Allschwil Meetings. He presented an update on his Emu48 software, including how the name became a brand. In the second part he described how he has given Warren Furlow’s HP-41 emulator a power update so that it now fully supports HP-IL via a PIL box.

Finally, another new speaker to end the day. Thomas Klemm (you may recognise the name from the HP Museum forums where he often posts helpful and informative answers) introduced us to the world of PostScript programming, comparing it with RPN. His example program prints a slide-rule on paper (simple assembly required!) and he came prepared with enough for everyone.


This year we decided to have a meal prepared at the venue, rather than go to a restaurant, so there was a break while everyone helped to clear and re-arrange the tables ready for a traditional Swiss fondue.

Overall the meeting went well and was very postive. I would like to thank all the participants who support us by taking the long (and not inexpensive) road to be here in the North West of Switzerland. Special thanks to Hans-Peter Bieger who offered to co-host after the last meeting. He advised and helped with the planning, organized the new location and did a lot of background work during the meeting to make sure everything ran smoothly. Thank-you very much for your help and cooperation, Hans-Peter.

Matthias Wehrli

(Fotos by HP. Bieger, text review by B. Horrocks - thanks a lot to you!)

november, 9th