HP Calculator

I remember in high school somebody had an HP calculator and I thought it was the craziest thing that there was a calculator without an = button. As I was entering engineering school I was told that there was some calculator we would eventually need to buy that was $500. At Christmas Mom and Dad bought me my first HP, a model 10C (which was *not* $500). This series of calculators became such an icon that they still sell the financial version, the 12C.


I lost it the next year while I was a Georgia State so when I went back to Vanderbilt I bought a recently discontinued HP-41C. This was the weaker younger brother of the HP-41CV and HP-41CX which must have been the $500 calculator I had heard of before. The 41 was completely programmable and could store 100 numbers. It could even deal with text. In fact instead of storing numbers you could store 6-letter strings of letters if you wanted. So I wrote a program that would store a 6-letter string and then, 20 storage registers later, would store a 10-digit number. You could browse through the strings and if you picked one it would show you the corresponding 10-digit number which was in fact a telephone number. No one knew it, but I had a PIM.

I wrote a lot of engineering programs for the calculator and used it through the Peace Corps and my first few years of Bridge Design. I heard that NASA had a backup navigation system for the space shuttle stored on a 41 (probably the CX which had more memory) in case their on-board computers failed. Everyone in Bridge Design had HP-41’s (mostly CV’s; I never met anyone else who had a C). They had even bought a card reader that you could attach to one of the four ports on the back of the calculator. They had these little magnetic strips that could store 50 lines of programming or so and a book to store the strips. I augmented the 41C’s woefully inadequate memory with a memory module called the “Quad mem pack” because it had 4 times the memory of a regular memory module. I also had an equation library module. My calculator was more powerful than ENIAC, the first computer, had been.

Eventually the buttons stopped working and it was time for a new calculator. By this time HP had introduced the HP-48. It had a 4-line display, built-in clock (and therefore a random number generator), graphics, infra-red communications port to transfer programs to other 48’s, a more advanced programming language, all kinds of commands, and 32 kb of memory. It had a cable that allowed it to communicate with a computer. It was the new gold standard of calculators so I bought a discontinued HP-48SX for about $120. I wrote all of my programs over again. Some people wrote programs in a machine language that was very fast and efficient and it wasn’t long before there were programs that would keep track of appointments as well as phone numbers and addresses. The random number generator and clock allowed for all kinds of games to be written. That new thing, the internet, provided fertile ground for sharing programs and tips.

Eventually Bridge Design bought an HP-48GX for me. It had 128k of memory which I needed because I was running out of space. I used the 48GX for the next eight years. To store a number on previous calculators you pressed STO 4 on the 10C (STO 04 on the 41C) to store a number in register 4. For the 48 you had to first create a variable name so you would type apostrophe, alpha, A, STO. Though once A was stored it was easy to write over it by choosing left-shift A. The calculator had menus and dialog boxes for everything. It was so complicated that it was almost cumbersome. But it was so much more powerful that it was worth it. When Bridge Design took a plunge into the metric system, the 48’s unit conversion functions were invaluable (we’ve since stopped doing metric projects) and some people gave up their old 41’s just for that.

Last week my 48GX died. Once again the keys stopped working. I figured I would just buy another one. I hadn’t kept up with the HP-48’s in a long time since I don’t do a lot of hardcore design calculations anymore, though I had started getting back into it as I am checking a lot of plans. I found out that the 48’s had been discontinued. A new replacement, the 49G, had taken its place. The calculator community howled about this. The calculator had rubber buttons that didn’t click when you pushed them (all previous HP’s had plastic clicky buttons that gave you “tactile feedback” indicating the button had been pushed, and only once). There were huge quality problems and lots of calculators dead on arrival. They had taken the infra-red communications away because students could potentially cheat on exams by sending information between their 48’s (unfounded because the 48’s infra-red only worked within a few inches). Worst of all, it had an = button for people who couldn’t figure out Reverse Polish Notation, one of the initiation rites of engineers, scientists, and financial wonks. The geek community mourned the loss of HP as the undisputed world leader in calculators. Some even switched to Texas Instruments calculators. E-bay was able to sell used 48’s for their full retail price.

But last year they came out with 49G+. The clicky buttons were back as was the infra-red port (HP realized that students taking tests weren’t their core market, plus they were starting to ban any calculator with alphanumeric memory). The calculator includes a port for an SD card allowing many megabytes of memory potentially. The processor is one that was on my first laptop, the Motorola 68000. Rather than use a custom calculator chip, they chose to use a computer chip running an HP-48 emulator that makes it act like a calculator. A USB cable connects it to your computer. Despite continued reports of keystrokes being missed (which subsequent releases of the flash ROM seem to have largely fixed) I went ahead and bought one for $130.

One of the neat things about this calculator is that it was essentially an advanced version of the 48, not a complete re-write. Supposedly all the programs (not the machine language ones) written for the 48 would work on this one. So as soon as I got it I wanted to beam a program to it from the 48. Apparently this couldn’t be done. You could only beam things from other 49’s. So I installed the software on my computer and hooked up the USB cable. Nothing. I looked in Help, went back to the old HP-48 newsgroup, tried a bunch of things and . . . nothing. I called HP. They spent nearly an hour trying a bunch of things, doing resets, re-installing drivers and . . . nothing. Meanwhile, in an effort to install a fresh ROM we succeeded only in wiping out the old ROM with no way to install the new one. So it now has the calculating capacity of a brick (with clicky buttons).

While it was working I found that they had reduced the number of buttons and increased the size of the screen to a 7-line display. But they shrunk down the numbers so it is harder to read the screen. And they’ve put all kinds of fancy higher math functions on there that I don’t use like matrices, graphing, equation solving, etc. So it is certainly arguable that quality and usefulness are still way down. In the meantime I scrounged another 48 from Bridge Design that had been used by someone who quit.

With computers and palmtops everywhere, the calculator is struggling to find its niche. If I need to transpose matrices, then I will be using a spreadsheet instead of spending a bunch of time inputting numbers on a calculator keyboard that probably are coming from a computer program anyway. What I want is something that will do all kinds of simple calculations with a few programs that take a few numbers for input (for instance, one program I have converts feet inches and sixteenths into decimal feet. So if a dimension was 1′-7 1/2″ then I could input 1.0708 (the last eight is the sixteenths) and it turns it into 1.625. Another converts back and two others take input in feet-inches-sixteenths and add them or subtract them). I don’t need much higher math but I do need trig functions, exponents, etc. And I need to be able to re-map the keys so that I can make the keys do what I want rather than what they originally did (so shift-7 might convert a number to feet-inches-sixteenths). A lot of energy has gone into making “graphing calculators”. Who cares?

3 thoughts on “HP Calculator

  1. HP sent me a new calculator to replace the dead 49G+. This one actually works and I was able to verify that the programs I wrote for the 48 work (for the most part) once I got them transferred. Still, I’m not crazy about this calculator. It is more of a student’s calculator. They would do well to come up with an engineer’s version that would do away with the graphing, vectors, equation solving, etc. and concentrate on doing calculations and running user programs better.

  2. Whats up Ted? I was looking for some feet inch software for my hp-48 g and came about your blog. I am a bridge detailer and am trying to find hp48 programs for doing things like you mentioned…feet inch calculations on the hp 48. I can’t program, and was wondering if you would be willing to part with some of yours. Thanks either way…..Regards, Chuck

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