Everyday use of programmable Calculators without Continuous Memory/Storage Devices

[Siegfried]

Quite a few of the early cheaper programmable HP calculators did not have persistent memory or a method to store programs. (Like the HP55, 25, 33E and 38E; I don't think there was a 29 or 34 without C.)

I wonder how people used those. Did they program them as required, keep a written "library" of programs to type in when solving a particular problem or just leave them switched on to save their programming work?

Overall the drawback of having to enter programs again and again can't have been too bad as these models don't seem to be particularly rare.

I would appreciate any recollections on this.

[Thomas Okken]

I had an HP-25, without the C. I had a small notebook with useful programs, and since none of them were more than 49 lines long, entering those programs only took about a minute each. The most frequently used programs, like the root finder and integrator, I knew by heart.

[Maximilian Hohmann]

Hello!

(12-17-2022 06:04 PM)Siegfried Wrote:  I wonder how people used those. Did they program them as required, keep a written "library" of programs to type in when solving a particular problem or just leave them switched on to save their programming work?

I can only talk for myself here, others may have done it differenty. I have used (*) a programmable calculator during my last two years at school, during all of university (aeronautical engineering) and occasionally later at work (but really only very little). Over a period of maybe ten years. Mostly it was my beloved Ti-59 which could even have stored my little programs on magnetic cards. But there are still some unused cards among the twenty or so that were supplied with the calculator. Simply because most of the programs were required only once. Some equations and constants required to find a solution for a given task. Tomorrow the task will be different enough so that yesterday's programs will not help solving it. No need to conserve them, another day, another problem. This I why I chose engineering and not bank loan management as a profession.

Regards
Max

(*) I have put the word "used" in bold because now I only collect programmable calculators and toy around with them. This is no proper use case for these machines that in their day were little wonders of engineering.

[Steve Simpkin]

I used my HP-25 for almost 10 years as my only calculator through high school, 4 years of college and 2 years at my first job as an electrical engineer. There were a few programs that I used semi-often (Lunar Lander!) and were documented but for the most part, I didn't need the same program twice so the lack of Continuous Memory was not a big deal for me at the time. I replaced it with a HP-11C in 1987 and really appreciated the non-volatile memory. My needs had changed by then and I built up a library of frequency used programs that I kept on the secession of HPs that I had after that.

[BobVA]

Pretty much the same here. I also kept a little notebook with a few frequently used programs in the case with my HP-25.

As I recall though, most of my "programming" was one-off / on-the-fly automation of repetitive calculations - for a particular lab exercise or class work - that didn't need to be saved / documented.

I wish I still had that notebook. Other than Lunar Lander, I can't remember what I had in there. :-)

[Allen]

(12-17-2022 06:04 PM)Siegfried Wrote:  I wonder how people used those.

More or less the same way people used slide rules without continuous memory.

[Siegfried]

(12-18-2022 05:57 PM)Allen Wrote:  

(12-17-2022 06:04 PM)Siegfried Wrote:  I wonder how people used those.

More or less the same way people used slide rules without continuous memory.

Now I finally understand why the ability to fill the stack with a constant was so important...

[Kostas Kritsilas]

In my college electronics classes, I used a Ti-58 (non-C version). The TI-58 used a "memory module" (a small plug in ROM, also used with the TI-59 and TI-58C) that contained application programs. There were memory modules that had electronics applications, but being a student, I couldn't afford those, so wrote and keyed in my own programs to work out various things that were part of our curriculum (setting up bias on a class "A" transistor amplifier, impedence of an RLC network, filter design, etc.) and carried a thin book of programming sheets with me that documented the various programs. Helped cut through a lot of the drudge work. It was tedious, but since I was a student, I didn't have the money to get the "latest and greatest" every time TI or HP came out with a new calculator, so made do with the TI-58. I would assume that most other people owning HP-25s, HP-55s, HP-33Es (and TI-55 and TI-57s) did pretty much the same.

[trojdor]

(12-17-2022 08:07 PM)Thomas Okken Wrote:  I had an HP-25, without the C. I had a small notebook with useful programs, and since none of them were more than 49 lines long, entering those programs only took about a minute each. The most frequently used programs, like the root finder and integrator, I knew by heart.

That is EXACTLY how I did it with my HP-25. I think I've even still got that spiral bound notebook around here somewhere.

[floppy]

(12-17-2022 06:04 PM)Siegfried Wrote:  Quite a few of the early cheaper programmable HP calculators did not have persistent memory or a method to store programs. (Like the HP55, 25, 33E and 38E; I don't think there was a 29 or 34 without C.)

I wonder how people used those. Did they program them as required, keep a written "library" of programs to type in when solving a particular problem or just leave them switched on to save their programming work?

Overall the drawback of having to enter programs again and again can't have been too bad as these models don't seem to be particularly rare.

I would appreciate any recollections on this.

No memory or card or USB or whatever for programm saving?
NoGo for me.
My HP12 is only for + and -.
I made already programs with several 100lines and a re-use was every time planned.

[Maximilian Hohmann]

Hello!

(12-19-2022 10:20 AM)floppy Wrote:  I made already programs with several 100lines and a re-use was every time planned.

In the past I got paid for writing programs which were run one single time only, after up to six man months of development time were put into them. Of course these needed to be stored during development, but after the single succesful run could be discarded. As I was working as a self-employed subcontractor then, I had to sign lots of agreements, among them one that forbode me to re-use pieces of my code in other projects. So I have no problems with not permanently storing programs, especially the kind that is required only once. (These were of course not pocket calculator programs but the kind that runs on mainframes and unix workstations required for the design of large aeroplanes).

Regards
Max

[Andres]

I had an HP-25 non-C and used it during the first years of my electronics engineering course, from mid 1976 to mid 1980, when I upgraded to an HP-41C. At the time when I programmed the 25, it was easy to enter programs by hand and from memory to solve exercises; for instance 2 x 2 simultaneous equations, root finders, random number generation and statistics, factorials, numerical integration per Simpson's rule, etc. I also had a binder whose pages were photocopies of the blank programming form included with the Application Programs handbook, and those forms were handwritten, they were handy to track register contents during program development. At the time, programs were short, simple and very procedural, so after learning the procedure, remembering the program was easy. It was kind of singing the lyrics of a popular song.