These were really amazing little machines, particularly for their time. HP had a custom CPU architecture optimized for low power consumption and calculator operations (think BCD floating point). By the time they got to the HP-28C and -19B, they had a custom OS/Language that had elements of both Forth and Lisp, and was pervasive throughout the software stack. (ie: the user programming language was a subset of the same language HP used to program the calculator itself.)
I still think the HP-41CX was the pinnacle. I did buy a 28(something) at one point but I didn't love it. It probably didn't help that, by that time, I didn't really need a powerful scientific calculator for work and would just do most things on a computer anyway.
You might also have liked the 42S... it was built to be as a more direct successor to the 41's. The UI is much more similar to the 41 than the 28/48/etc.
> I did buy a 28(something) at one point but I didn't love it.
The 28/48 was much more powerful, but it was also a fairly radical shift in approach. The interface got heavier weight, with more to interpret on the display, more keystrokes for many operations, and just generally more to manage. I liked it, but in retrospect mainly because it was a portable computer I could play around with during school, etc.
I think it's also the case that HP's interest in the calculator market was falling off right as RPL (19B, 28, 48, ...) was hitting its stride. TI took over the educational market starting with the TI-30 and TI-81, and computers took over the professional market - so there wasn't much room anymore for a professional HP calculator by the time the early 90's rolled around. (Or at least not enough of a market for the calculator business unit to gain traction within HP to fund its development efforts. My guess is that, as is often the case, the opportunity cost of pursuing a relatively small market was viewed to be excessive when there were other things to do.)
The contrast between the 1972 introduction of the HP-35 and 1993's 48-GX is also striking. The HP-35 got developed because the 'H' of HP wanted it, and even then, he commissioned market research studies and held back the usual development funding. Once developed, the HP-35 sold well, even at >$2K 2016 dollars, due to the fact that the best alternative was either a slide rule or a minicomputer. If it took that much political power within 1972-era HP to sell a product with a such a compelling advantage, it's not hard to see how badly the complete landscape shifted against further calculator development by the time the 90's rolled around.
All that's to say that the RPL platform only got a couple rounds of significant internal development funding by HP. At one point, I'd have really liked to see what they could've done with another round or two of development. And then I graduated high school, got more access to real computers, and it didn't really matter any more.
Those go for some pretty good money, don't they. I actually just picked up a couple of things that I can hopefully use to repair my HP-41CV.
>The 28/48 was much more powerful, but it was also a fairly radical shift in approach.
Yeah. I think that was the thing. I'd been using an HP-55 since the campus store had some almost affordable overstock in about 1977. (When I started college, I got a TI scientific calculator because the HPs were still so pricey. Pricing dropped pretty radically over a few years.) I picked up the 28S at one point but I didn't really need a calculator by then for anything fancy and I never got into the UI and clamshell ergonomics.
Nice collection. I'm jealous. I missed out on the 15C re-release when it was available. I don't really have a use for it, but I really did want one.
I've got a couple of 12Cs and an 11C. I use them occasionally, whenever I need to do some maths that's not complicated enough to warrant firing up Excel but too much for my feeble mental maths.
I don't remember how I was lucky enough to find out about the 15C in advance, but I jumped all over that.
Several years ago I took a university final and the requirement was a non-programmable calculator. I looked on eBay and discovered how expensive an 11C would be, so I went to the professor and explained that I was by this point in life incapable of using an algebraic calculator and pleaded to be able to use one of my HPs instead. Thankfully he didn't care.
Awesome! On a side note, if anybody finds themselves near Bonn (Germany), do yourself a favor and visit the Arithmeum.
"The Arithmeum presents the history of mechanical calculating machines, as well as the computing of today, in an aesthetically pleasing environment. Many demonstration models invite the visitor to discover the historical milestones of mechanical calculating, and at interactive multimedia stations the visitor can develop small microprocessors in a playful way. Early highlights in the development of computers are also exhibited."
He used it even though he had an electronic calculator. Common business calculations seemed to perform much faster and more reliably than on the electronic calculator (1980s). You had to check every single number and operation you typed into the electronic calculator, but you could do quite a bit without looking, just by feel, with this mechanical one. Multiplication for example, you just turn the crank handle for each round.
Strangely (I think) this doesn't mention the Sinclair calculators, one of which I purchased in the mid-Seventies and still have in a box somewhere. It was minimalist but gorgeous. I'd like to dig it out now and carry it around... would be v hipster.
If you like old calculator hacks, you might be interested to know that some early calculators (such as those from Wang[1]) could natively perform only addition, subtraction, e^x, and the natural log. So to multiply numbers, they took e^(ln(a) + ln(b)). See also: factor combining [2]
Interesting website, clearly a ton of work went into it. If you are like me, and full length paragraphs are impossible to read for you, here's a handy bookmarklet I use for such websites:
I collect old calculators myself! These old machines are really gorgeous things, usually handmade (at least until the early 70s.) If anyone on HN has questions, I'd be happy to answer.
Mach 1 Slide Rulette - made in 1972, one of my older ones. Has a really nice glowing green VFD, vacuum fluorescent display. Obviously very well made.
Sears M8 - made in 1973 by Sears, came in a nice black leather carrying case. The side of the calculator has an orange stripe down it, which makes the whole thing look gorgeous.
Sharp EL-827 - made in 1981, my #1 favorite, a musical calculator. It's fairly quiet, but you can hear it in a quiet room easily. The keys each have different notes for them, so you can play songs on it. I've learned a handful of songs on it myself. A really tiny, little, gorgeous thing - slimline, brushed metal, super thin. Just beautiful.
Sure. Musical calculators were initially made for the blind (so when you press a key, you hear a sound and can tell what's happening.) When you press equals, for example, the calculation happens and the calculator sounds out the tones for the answer - for example, you enter 9x9=81, and you get (9 tone) (multiply tone) (9 tone) (equals tone) and then the calculator sounds out (eight tone) (one tone).
Eventually people started using them as toys or musical instruments, so some calculator companies started making the sounds less robotic and more musical - and now there are "musical calculators".
Still have ny HP41C, with XMEM etc, but no longer carry it with me since i41CX came out for the iOS devices. Inludes all the rom extensions too. When I get the energy the system is for sale - printer needs new batteries, card reader needs TLC or replacing. I also had but sole an HP16 programmers calculator, since there is also now an iOS (and OS X) version. PRG 16C. My first was a Bowen around 1964/5, then an HP 35 in 73?. Sharp made what is likely the first BASIC programmabe (actually they labelled it, I recently found several OEMs of it) that really impressed me. I have no idea what happened to mine. Also have still a Radio Shack Programmer's calculator.
I wish they had an emulator for each that would display values visually as close to the original as possible. You could then test them each out to see how the following result is displayed:
I just spent an hour reading that same entry, absolutely amazing tech for the time and that they got that to work reliably enough for a mass market product is really amazing engineering.
http://www.hpmuseum.org/
A more user-oriented HP site is here: https://www.hpcalc.org/
These were really amazing little machines, particularly for their time. HP had a custom CPU architecture optimized for low power consumption and calculator operations (think BCD floating point). By the time they got to the HP-28C and -19B, they had a custom OS/Language that had elements of both Forth and Lisp, and was pervasive throughout the software stack. (ie: the user programming language was a subset of the same language HP used to program the calculator itself.)