»RCL40: Recollection, Reinvention and HP Calculators«, edited by W.A.C. Mier-Jedrzejowicz, Mark Power & Bruce Horrocks, pp 60-67, HPCC, UK, 2022

Friendly Competition

Dejan Ristanović reminds us that Texas Instruments' calculators were significant competitors Hewlett-Packard's machines and that there was a thriving user community for both

RCL40 Book

Programable calculators have shaped my life. They made me chose a profession, start my carrier, even earned me some money. I love computers, I love programming, and still cherish that wonderful feeling when you manage to squeeze a few more bytes from an already optimized program in order to fit it into that meager one kilobyte of available memory. But the best feeling is when you finally meet other people sharing the same interests.

It all started in July 1979, when I saw a TI-58 programmable calculator in the second-hand shop. Why second-hand shop? Well, I was living in former Yugoslavia, behind the curtain. Not the iron curtain, but there was some kind of a soft curtain between Yugoslavia and the Western World. For example, we were not allowed to import anything costing more than about $25. But we were allowed to travel, so some folks made a living by traveling to neighboring countries, buying technical goods, smuggling them across the border and selling them for a significant profit. Second-hand or "commission" shops were a semi-legal way to distribute these goods. The TI-58 I saw was brand new and the cost was 6500 dinars, about $340, which was probably 150% of the US price.

I did not know that programmable calculators existed, in fact I first read the term "programmable calculator" on the surface of the TI-58 case, but it looked so great and so complex that I had to have it. I bought it on July 23 and knew that I had a great way to spend the summer vacation after my sophomore year at the Mathematical High School.

I knew absolutely nothing about programming, and the manual was of no great help since it was written in Italian; the calculator was obviously smuggled from Italy. I did not know a word of Italian, but I bought a dictionary and started word by word, page by page, example by example. I did not learn any Italian, but I did learn TI-58 programming, and by September I wrote a Mastermind game, some math routines like solving the quartic equation and other simple stuff. My friends at school were thrilled by the calculator itself, especially by Master Library programs that could find zero of a function or solve a definite integral. My programs did not cause much enthusiasm, maybe because TI-58 did not have the magnetic card reader, so I had to retype the whole program before I could demonstrate it. Nobody had such a calculator, so I was not able to discuss my findings and my problems.

But I was nearing the end of the TI-58 manual and found a note that one could send his own programs to some address in Texas, USA. So, I wrote a long letter, enclosed all my programs, and sent them, hoping for some miracle to happen. And it did. A month or two later I received a kind letter from Texas Instruments with some catalogues and literature in English. Among other things, they sent me addresses of users clubs in the USA, Germany, Belgium, Sweden... So, I started writing letters, exchanging programs, making friendships. By mid 1980 I had articles published in TI PPC Notes, the leading TI-59 related publication edited by Maurice E. T. Swinnen (1926-2021), also in the Plewnia club's newsletter edited by Peter Poloczek and Thomas Edling, programs accepted by the TI Software Exchange Library in Kappelen, Belgium, founded by Thomas Coppens. Quite a few of my classmates purchased TI programable calculators, so I founded a local club and started a series of articles about programmable calculators in the popular science magazine Galaksija (Galaxy). I also found a way to purchase TI-59, a compatible but more powerful calculator with magnetic card reader, and a thermal printer PC100C.

Everything was wonderful, but then seemingly out of nowhere came the disturbance. In early 1981 a classmate brought a brand-new HP-41C calculator. What a machine - it allowed the use of alphanumeric characters, had continuous memory, and the ability to store many programs and assign them to various keys. I could not afford to buy another calculator, so I had to convince myself that my TI-59 was much better. To start, HP-41C used some awkward RPN notation, while TI-59 used "more natural" AOS. The memory was only about half the memory of my TI-59 (my classmate did not purchase any additional memory modules), there was no Master Library module with useful programs... Still, those alphanumerics and the continuous memory attracted me, and I finally got a HP-41C on loan, studied its potential, decided that RPN is actually superior to AOS, at least for an experienced user, that there were many modules and peripherals... In the end, I could not live without it, so in 1982 I found the money to buy a HP-41CV with a card reader and thermal printer. What a day that was!

I immediately joined PPC and subscribed to the PPC Calculator Journal, but I was somehow late to the party. The most amazing discoveries have already been made, synthetic programming was common knowledge, and the astonishing PPC ROM project had concluded a few months previously. But the Journal was still a great publication and I dreamed of publishing an article there. Then I ordered some back issues and, to my amazement, found out that I had published at least three articles in the Journal. How come? Well, some time in 1981 PPC decided to incorporate, and in order to qualify for tax exempt status, they had to support the devices produced by more than one manufacturer. So, they began reprinting (with permission) parts of TI PPC Notes, and some of my programs ended in the Journal.

I still wanted to publish a real HP-41C program. Fearing that I had not accumulated enough knowledge and experience to do so, I decided to rely on the TI world, at least in part. I wrote a "TI-59 to HP-41C Compiler", a program that translates TI-59 programs to the HP-41C programming language and stores them in the HP-41C's memory. It used synthetic programming and worked quite well, although some of the things could not be translated, for example the direct mode addressing. The program was published in PPC Journal v9n6p27-29 and attracted some attention. I received a bunch of letters with questions, problem reports and suggestions. Nowadays it seems strange to think about letters on paper, expensive air-mail postage, slow delivery, and other barriers to communication, but everything worked that way. It was slow and costly, but it worked.

Later that year PPC Journal stopped reprinting TI PPC Notes articles, since that idea was not very well received by the membership. TI and HP calculators were separate worlds and stayed that way. However, some contacts between those worlds remained, and the most interesting one was the calendar printing challenge or, as it was frequently called, the friendly competition.

It started in May 1978 when the first calendar printing program for the TI-59/PC-100 was published in 52 Notes, the publication that preceded TI PPC Notes. The program was written by Jaren Weinberger and Lou Cargile and required 34 minutes to print out a year calendar. Richard Vanderburgh, the 52 Notes editor, challenged the users of PPC Club and PPC Journal editor Richard Nelson to produce a faster calendar printing routine.

The next issue of 52 Notes published a set of programs produced by Lou Cargile, Fred Fitzgerald, Bill Skillman, Panos Galidas, and Maurice Swinnen. The resulting program printed calendar in 5 minutes. The following month even more programs were published, and the time was under 3 minutes, even 2 minutes and 39 seconds. At that time the best scores for the HP product line were around 6 minutes, since HP's flagship calculator, HP-97, was no match to the TI-59. Soon after the introduction of the HP-41C, in early 1980 (PPC Journal v7n6p14), Roger Hill wrote a program for that machine which would print a calendar in 2 minutes 19 seconds, thus taking the lead for the HP product line for the first time.

That lead was short-lived. A few weeks later, Martin Neef discovered the fast mode for the TI-59. Using an obscure Master Library call, Martin managed to put TI-59 in some special state where display was not refreshed after each instruction, but the execution time was cut by almost 50%. Palmer Hanson rewrote Panos Galidas' program to use the fast mode and produced a program which would print a calendar in only 1 minute 32 seconds, which was later cut to 1 minute and 26 seconds by interleaving print commands with other instructions, so that the CPU would continue while printing was in progress; that parallelization saved a few valuable seconds.

Roger Hill responded with an HP-41 program which would print a year in just 1 minute 14 seconds, that was just one second more that the theoretical minimum printing time (PPC Journal v7n8p15). So, Roger won the contest, although in March 1984 Patrick Acosta incorporated fast mode entry using the h12 (hex code) technique into Palmer's program, which reduced the print time for the TI-59 to 1 minute 26 seconds. However, Roger's record was undisputed.

Texas Instruments calculator users were hoping for a new model that could swing the pendulum back to their side, and that calculator came... sort of. The TI-88 was introduced in May 1982, a number of samples were produced and even sold, some programs were written, many articles published, but a few months later TI discontinued that model and obviously lost interest in programmable calculators. We all felt very disappointed.

Apparently, the decline had begun, and by early 1984 I got the feeling that the era of programmable calculators was coming to an end. Richard Nelson resigned from PPC, Maurice Swinnen transferred TI PPC Notes to Palmer O. Hanson, the official HP library in Geneve (UPLE) folded, HP Key Notes magazine also folded... People gradually shifted their interest to home computers, so I purchased an Acorn BBC model B computer and stopped subscribing to calculators-related journals. For more than a decade I was out of that world.

And then came the Internet, so I wanted to contact some of my friend from the old days. I found out that their enthusiasm was stronger than mine. Palmer published TI PPC Notes until 1992, and the PPC Journal was published until 1987. I had a déjà vu feeling of having my articles published in the PPC Journal without my knowledge. They frequently published old material which was initially rejected, and even re-published already published articles. Richard Nelson started a new club, CHHU, and produced a high-quality journal which, due to the insufficient number of subscribers, lasted only about a year and folded in early 1986.

In the new millennia, little was left of the TI social network, but the HP social network survived. Maybe because HP produced a worthy successor to the HP-41C, the HP-48 line, but even the HP-41C scene was still active - that calculator simply refused to die. People shifted their interest to machine code (microcode) programming for the HP-41C, which is an art that I never mastered. They produced a number of custom ROMs taking synthetic programming to the new level. Conferences are held annually, to this day - the HHC 2021 Conference was held in Nashville, Tennessee from October 2 to October 3, 2021. In the long run, one could say that HP people won the friendly competition, as proved by the magnificent RCL 20 book. Now we are aiming at RCL 40, but who knows, maybe we will live long enough to produce RCL 60. We might have to change SIZE first.