Great your older brother from me. He was our tutor during his military service at st Cyr.
I myself had an hp48 during my high school and now I own 6 of them I bought on Leboncoin or eBay for cheap. Also found an hp32sII for 5 euros but after three years I own it it decided to die in my hand.
Most of the models seems to age well except for the rubber-like connector between the key plane and the motherboard, and the keys are either not registering presses or you have to press hard on the body.
I don't remember exactly, have to look it up. I think it was a 48GX. But the problem is sending electronic items to the US is a real PITA. I'm in Europe myself. We shipped a MacBook with work one day from the US to EU and it would have cost us more than the thing was worth in import and brokerage charges, it was ridiculous :( In the end we had to decline and the thing went back but it still incurred a lot of charges there.
Ah the UK is also a problem now unfortunately :( Thanks to Brexit. But sending to France might be doable if that could work (I'm Dutch, in Spain). I'll have a look for it and ping you.
I’m looking for memory card either diy or genuine. Do you know if it exists anymore ? I often find custom Ron card with specific application (EE or advanced physics) but I cannot find 1mb black card for sell.
Blast from the past for sure, OP was not but I was in Paris in the early 90s, and HP48 hacking was huge. I remember attending class, ignoring the teacher, and just patiently leafing through long print outs of HP48 disassembly, or typing in assembler programs on the calculator itself.
The software on this thing was pretty amazing, but surprisingly hacky in some ways. The RPL language had a system of embeddable objects in memory, but when the interpreter had to skip over an object (i.e all the time), there was no field marking its length, so it had to actually recurse through all the sub-objects to find the end.
IIRC there was the a hack where some memory locations could contain a direct pointer or a pointer to a pointer, and it would work either way because the same bits could be interpreted as a pointer or directly executed... or something of that sort.
The French HP48 phenomenon was always interesting to me. How did that happen? I'm in the US and we had a French high school student visit over the summer. Always talking about the HP48SX, though he didn't bring it with him. But when I needed to get a graphing calculator I ended up buying an HP48GX instead of the recommended TI-83 (I ended up getting one of those as well). I used the 48GX throughout middle school and high school w/Meta kernel, Erable - the developers of which all French, ended up working for HP ACO. Used a 50G later on. It was always interesting to me how the development powerhouse for the HP48 series was all French, but never really understood how that happened. Was there some schooling mandate similar to TI in the US?
It was a hacking scene with a few talented guys with strong enough personalities to organize meetups and write fanzines articles.
Also, the model was popular in preparatory schools because of the expansion slots, it was possible to extend the memory by a huge margin.
This memory was useful to store, well everything you could, and at the time those calcs were not forbidden during exams.
Some people (including me) even wrote text editors and viewers with support to display a mix of text and picture for schematics, physics or chemical diagrams...
The US scene was also extremely helpful, with people such as JK Horn or Eric Rechlin.
Most schools recommended TI instead of HP (at least in the late 90s). The few people I knew who also had an HP48 or HP49 tended to be enthusiasts and all ended up studying CS at an Engineering school.
I have the strong feeling that hp28/hp48 have a deep impact in IT industry given the number of smart and passionated peoples who self taught themselves low level programming before 18yo with them.
Im 43 it guy and started playing with hp at 12, my own first « computer » with countless hours: playing, coding, debugging, reading txt files. Naturally when I bought my first intel computer at 19yo I installed freebsd, to later go to openbsd and Linux.
And the first thing I do on my android phone is to install hp48 emulator.
Most of the people who were active in the HP48 scene turned out to be good to great coders with a good knack for low-level optimization.
You may have heard of LZ4 or ZStd, the author is a French guy (currently employed by Facebook) who started hacking compressors on his HP48, this is how I met him a long time ago.
It had pretty good hardware I would say for the tradeoffs involved. One thing you should remember is that 30 years ago, the current semiconductor processes meant that if you put a faster/more capable CPU or color display tech in it, it would not last very long on batteries. The HP48 had phenomenal battery life on 4 AAA. A hand held gaming system like a game gear or Atari Lynx would last only a few hours on 6 AAs.
I really loved learning how to push this little gem to its limits, so many tricks were possible with the weird addressing schemes.
(I wrote a hobby OS for the HP48 series when I was a student)
https://www.hpcalc.org/hp48/apps/shell/