The Flight That Made The Calculator And Changed The World

It was the fall of 1965 and Jack Kilby and Patrick Haggerty of Texas Instruments sat on a flight as Haggerty explained his idea for a calculator that could fit in the palm of a hand. This was a huge challenge since at that time calculators were the size of typewriters and plugged into wall sockets for their power. Kilby, who’d co-invented the integrated circuit just seven years earlier while at TI, lived to solve problems.

Fig. 2 from US 3,819,921 Miniature electronic calculator
Fig. 2 from US 3,819,921 Miniature electronic calculator

By the time they landed, Kilby had decided they should come up with a calculator that could fit in your pocket, cost less than $100, and could add, subtract, multiply, divide and maybe do square roots. He chose the code name, Project Cal Tech, for this endeavor, which seemed logical as TI had previously had a Project MIT.

Rather than study how existing calculators worked, they decided to start from scratch. The task was broken into five parts: the keyboard, the memory, the processor, the power supply, and some form of output. The processing portion came down to a four-chip design, one more than was initially hoped for. The output was also tricky for the time. CRTs were out of the question, neon lights required too high a voltage and LEDs were still not bright enough. In the end, they developed a thermal printer that burned images into heat-sensitive paper.

Just over twelve months later, with the parts all spread out on a table, it quietly spat out correct answers. A patent application was filed resulting in US patent 3,819,921, Miniature electronic calculator, which outlined the basic design for all the calculators to follow. This, idea borne of a discussion on an airplane, was a pivotal moment that changed the way we teach every student, and brought the power of solid-state computing technology into everyday life.

TI showed the Cal Tech prototype to a number of companies and Canon took an interest. Canon brought it to market as the Pocketronic, releasing it in Japan in October 1970 and the US in April 1971, selling for around $150 ($910 in 2017 dollars). It had three chips and a heat-sensitive paper tape readout. It was still just handheld though, not really pocket-sized, but sold very well.

By then a number of other handheld calculators were also hitting the market. In November 1970, the first calculator-on-a-chip, the Mostek MK6010, was announced, followed in February 1971 by the first truly pocket-sized calculator, the Busicom LE-120A “Handy” that used the chip. That same year, TI followed with their own calculator-on-a-chip and in 1972 TI started releasing its own calculators.

HP-35, the first scientific calculator
HP-35, the first scientific calculator, by Seth Morabito CC BY 2.0

In 1972 Hewlett-Packard released the HP-35, the first scientific calculator, one that could replace a slide rule. It used reverse Polish notation (which our own [Jenny List] recently wrote about), included scientific notation and had 35 buttons, hence its name. Despite a $395 price tag ($2,320 in 2017), 100,000 were sold in its first year. The HP-35, along with the release of TI’s equivalent SR-50 in 1974 for $150, spelled the end of the actual slide rule. (The SR stood for Slide Rule.)

Display technology also advanced through vacuum fluorescent displays, LEDs and LCDs. In the mid-1970s, twisted nematic (TN) LCDs gave calculators the now omnipresent dark numerals on a light background while decreasing the power requirements to the point where they could run on button cells.

Prices dropped as new features were added and sales doubled each year. By 1976, a four-function calculator cost only a few dollars. In 1972, 5 million calculators were sold in the US and within ten years there were more calculators in the US than people.

Why had the calculator become so popular? This was a clear case of a consumer product that was conceived for a market that wasn’t known to exist. When Haggerty conceived of the idea in 1965, calculators were heavy and took up significant space on a desktop, so perhaps the convenience of one which you could carry around played a part. They also needed no setup, no programming — simply flip the on/off switch and do some calculations. For the average person, they replaced the need to learn multiplication tables, necessary for working out how much a dozen apples would cost at $0.05 an apple. They also made it easier for the high school student to do the trigonometry in their physics homework. Though, in the early 1970s, given the initial high price, perhaps it was engineers and companies that bought them first.

TI-30, by D. Meyer CC BY-SA 3.0

I can attest to the latter. I was just becoming a teenager back around 1976 when my father bought a TI-30 calculator for $25, or around $107 in 2017 dollars. The mining company at which he worked as an electrician had made them available. Before that, I recall using long division to divide up a long sheet of paper for a mural that was to be a backdrop for a school play. I would likely have gone on to learn to use a slide rule, but never did. After the calculator arrived, I’ve done long division on paper only once when no calculator was available, though I have done it for fun and to see if I remember how.

TI-81 graphing calculator
TI-81 graphing calculator, by Calcvids CC BY-SA 3.0

Through the decades that followed, calculators continued to gain functionality. In 1974, HP came out with their first programmable calculator, the HP-65. It had 100 functions and stored programs with a magnetic card reader. Starting in 1978, a company called Calculated Industries released very niche calculators such as the Loan Arranger for the Real Estate industry with functions for calculating payments and future values. Then later came the Construction Master with programmed functions for pitch, rise, run, feet-inch conversions and more. In the 1990s TI came out with the TI-81, a popular graphing calculator for algebra and precalculus courses and power by a Zilog Z80.

If memory serves, it was a programmable Sharp El-5040 with a single line formula display that I’d left behind in a University auditorium, hopefully having found a good home on an engineer’s desk. Now, my Sharp EL-531W, also with a single line formula that can be retrieved and edited, sits ever-present beside my computer monitor, getting daily use while a Casio fx-3600P that I’d thought I’d lost but later found, sits waiting for its turn in my desk drawer.

This being Hackaday, you no doubt have a calculator that gets frequent use. Or perhaps you have your own fond memories of one that got away or a family one that you grew up with. Or perhaps there’s one you’ve hacked, like this ESP8266-connected scientific calculator? Share your stories with us, we’d love to hear how the calculator has played a part in your life. We also wonder how much longer the calculator as a distinct piece of electronics will survive now that the infinite adaptability of smartphones has made calculator apps the go-to for today’s upcoming engineering candidates?

[Pocketronic photo used in main image via Dentaku-Museum]

89 thoughts on “The Flight That Made The Calculator And Changed The World

  1. I have a cute calculator story.

    When I was in high school, I saved my pennies for an HP41CX. That was the last calculator I used routinely, and mostly for writing and playing games. After that, mostly used ‘bc’ as my calculator. And it was that way until the iPhone came out.

    For most of that time, I had an Advanced class amateur radio license. I didn’t go for Extra because of the code requirement, but when that was dropped, I came back to get that.

    The thing was, that exam had some math in it. You are allowed to use a calculator, but it can’t be a “smart” or “connected” one for obvious reasons.

    So I went to a drug store and bought a “dumb” Casio scientific calculator just to use for that half-hour or so. I haven’t touched it since and it’s probably been thrown out by now.

        1. I once stored a harry potter book in the program memory of my Casio FX 1.0 just to see if it was possible. It was. Reading it was not easy, but point proven: it could be used to cheat in exams with mixed math and essay answers.

          The calculators were supposed to be reset, but nobody ever checked.

          1. I stored a few equations on my programmable calculator for a physics exam in the 90s. Schroedinger and Pointing if I recall correctly. Didn’t need them though.

        2. My professors were of the mindset that if you went to the effort and requirements to program EE solutions into your calculator, then you understood the content and execution much more than memorization could accomplish. Also, that would be how one would work at a real job. I don’t close my books when faced with a design problem, quite the opposite. Still use my 41CX on a daily basis.

      1. When I took my PSAT in high school (late 90s) the rule was you couldn’t have a calculator with a QWERTY keyboard, so my HP100LX was out, but my HP 48SX with the full equation library was just fine :-P

    1. I have a 25 cent-at-a-yard-sale Casio fx-280 on my desk right now, often because I have the calculator app on the Mac open somewhere on my 10 virtual screens and it’s easier to find…I have a dozen more floating around my house that have collected over the years. (including a casio Fx702 P BASIC programmable one)

      My very first one was (iirc) by National Semiconductor that was a 4 function 9 digit fixed 2 decimal place that I got for $19 in about 1974. learned to carry decimal points in my head with that one.

  2. Daily use out of the calculators on my PC and phone and still have a Casio in the workshop just in case. But, when I’m designing my personal recumbent and/or cargo bikes, I like to go very old school with an Aristo slide rule.

  3. “seemed logical as TI had previously had a Project MIT.”

    is that supposed to be ‘at’? Still doesn’t make sense, I don’t understand how “texas” relates to “massachusetts”.

    1. TI had a project that they had called “Project MIT”. So it seemed logical to Kilby to name this next project after the California Institute of Technology, commonly known as Caltech (though he chose to write it as Cal Tech). I guess the idea was to name projects after tech schools. It was sort of also logical because the “Cal” could be taken to mean “calculator” but in a way that was illogical too because it was supposed to be a secret project, hence the code names.

  4. I was the last generation to use log tables, trig tables, and sliderules, though scientific calculators were available and expensive. The first programmable I had was an HP11C, though I had an HP35 before that as my first scientific. I still have them both, and the 11C sits on the desk in my shop and gets a fair bit of use. The 35 still works, thought only on wall power, but doesn’t get much use. I don’t want to wear out the buttons or risk damage to it.

    I never did have much use for a graphing calculator, as by the time they became available, I was already in my career and had ready access to at least mid-range computer with much better tools. To the extent I have played with one, I am not really impressed. Some of the smart phone aps, and the ability to use tools like Alpha on the phone, are significantly better, though it has been a few years since I looked played with an actual calculator, so they may have improved.

    My favourite calculator, though I never use it anymore and it was obsolete before I got out of school, is my 20 digit Monroe (mechanical). Add, subtract, multiply, and divide. About 0.5s cycle time. Adds in one, mult in mn, where n is the number of decimal digits in the multiplier and m is the mean of the digits, and divide in mn, where n is the number of digits needed in the quotient and m is the mean of the digits in the divisor. I don’t recall how to square root using it, but it was faster than looking it up if more than a couple digits were needed.

    1. I got a HP11C when I entered college, and used it until the late 1990’s; I was heartbroken when it stopped working. Later snagged one of the 15C Limited Editions. Lately I’ve been eyeing up SwissMicros’ product line thinking of the credit card sized 11C clone they have available…

      1. I have two ‘real’ calculators in my desk drawer that I use all the time, the HP15 and the HP16. I have emulators for the 15 on all my computers and tablets. In my opinion these HP calculators are the perfect ideal of what a calculator is to be. But then I still have my KE slide rule…

  5. Well, it looks like somebody missed out about 10 days ago: at my calculator stand I showed most of the above mentioned machines.
    + Canon Pocketronic (mine not working)
    + HP-45
    + HP-41C
    + HP-19C
    + TI-30
    + TI SR-50
    + TI SR-56
    …just to name a few (roughly 30 in total)

    For HP calc lovers check out – they build AFFORDABLE replicas of HPs Voyager line + the 41 and brand new the 42.

      1. (I didn’t want to go that far… but you are asking :^)

        I had Mr.M.S. of SwissMicros as a guest at my stand: he brought almost the whole palette of theyr products to complement my exhibition.
        YES: incl. a pre-series DM42! (one of the 100pcs pre-production run) It was nice being able to show both the original HP-42S and the DM42 side by side.

        So I know firsthand that DM42 will be available from December on – that’s what “soon” means here :)

      1. Ah yes, same here! My “file storage” was writing out programs on index cards. I was particularly intrigued by the random number generation routine in the supplied manual, I didn’t understand the maths behind it at the time & have forgotten the specifics now – but it didn’t use any equivalent to rand(), it was just “procedural”.

  6. In the early 1970’s I worked at TI in Stafford (South-West of Houston), where I worked on the systems that tested TTL IC’s and later the systems that tested MOS IC’s, including the 3-chip calculator IC’s mentioned in the article. When the SR-50 came out, I was working for TI in Silicon Valley, on their mini-computer systems, and bought one. It was a very nice calc. In 1975 the SR-52 Programable Calculator was released (, and had a magnetic card read/write built in. The card was read or written to, and then slipped into a slot above the function keys for labels. I used that thing for years.

  7. I used and loved the HP 48G throughout school, but haven’t used it since because desktop and phone apps are more powerful and convenient. However, I think standalone calculators aren’t going away anytime soon because of the academic market. Professors aren’t likely to ever allow students to use smart phones during tests.

    I did see an interesting stackexchange question recently ( where students were cheating by using hacked calculators with replaced circuit boards. Interesting that this sort of hack is now feasible. Personally, I think schools should learn to teach and test on higher-level concepts instead of things a computer can do for you.

    1. To be able to effectively implement the higher level concepts, you need to know the “things a computer can do for you” well enough to do them, at some reasonable level. At one of my positions, I spend most of my time either proving to the guys that are “higher level thinkers” that their ideas won’t work, or doing what they said can’t be done while they watch. Testing on the higher level concepts requires that the students also understand the basic concepts.

      Every time one of the experts/TED talk fans comes into tell us that he can know everything I do in five minute because google, I ask if that means a parrot knows calculus because it can say “the derivative of x squared is 2 x”…

  8. My mostly used calculator are the Wabbitemu app with Ti-83+ ROM on my phone, and my old real Ti-83+ at home at my hobby desk. Really handy to always have the same calculator with me on my phone as at home, prefer the real thing, when its there though. Then I have two old Casio FX-82LB, one att work because sin functions are really handy working with angles and such in steel, and can be used with workgloves and I dont care if they ever will break due to grime and oils. The phone Im more carefull with.

  9. I remember using my Ti-85 (my parent’s wouldn’t spring for the newer 86 that had the cable) to cheat in class, typing much abbreviated notes into “programs” ahead of time :)

  10. When pocket scientific calculators showed up, I was in high school for geodetic… and was pretty disappointed by the number of digits available : we made heavy computation to calculate a precise position from known points or star observations : spending a good part of the night pointing instruments toward stars and the next morning trying to figure out an exact position with sinus tables and 4 operations mechanical calculators (I still have one : doing a multiplication, you have at least 20 digits for input and even more for the result).
    So we had to wait a little longer before using pocket calculators…

  11. If you’re interested in this story, or the story of Jack Kilby then you should check out the book “The Chip” in it you’ll find great antidotes of the creation of the IC, along with the opening paragraphs of this article almost verbatim. The book will further explain the meaning behind their project code words.

    So OP read the book, used that to open and then found a bunch of calculator facts? It’s interesting and all, but seems a bit of “content for the sake of content”?

      1. The irony there is that there was *plenty* of color in the movies – and not just full color film, but hand-tinting of frames for effects and so on. What *really* made the world monochromatic was television, where there was just no way to make colored output until multi-gun CRTs with color phosphors and masks became a thing (yes, Atari vector games like Star Castle and Batlezone were done with monochrome CRTs with colored gels in front, but that was years later).

    1. “antidotes of the creation of the IC” would be drugs to counteract the creation of the IC. Perhaps you meant “anecdotes about the creation of the IC”? If you are going to be negative about a post, at least be accurate.

  12. I have a HP35S and a real HP16C in front of me right now, and the same at home. Both calcs are in daily use. Had to change the batteries in the ’16 this week, only get 2-3 years daily use out of them. The 35S stills misses the occasional keystroke. Anything more Wolfram Alpha is my friend. Came through high school with Eton log tables, then a slide rule, then Sinclair calculators. Made quite a few Sinclair Scientific kits to fund my first HP35 in 1974.

  13. TI-89 or HP-48GX are my faves hands down. I still use a TI-89 every once in a while and use the TI-89 emulator in my phone as my primary calc. The 89 is FAR superior to the 83/84 peddled by high schools.

    The HP-16C is kinda neat… wouldn’t mind having one as well.

  14. I seem to remember that my first calculator had a moon lander programme built in or maybe you had to enter it on the keypad, I can’t be sure. You entered a fuel burn and the display counted down feet to touchdown when you got it right. I usually ended up either heading towards Betelgeuse or making a crater. I spent a lot of time playing that.

    I can’t remember what the calculator was but I think it was ti.

  15. I still remember writing games and math stuff and things on my Casio CFX-9850G graphics calculator in high school. And playing games in class as well. The CFX-9850G was what my school standardized on but for the high-school-finishing-exams in the math classes where you were allowed these things they had a list of approved calculators (other exams just allowed a scientific calculator “no graphical display and no alphabetic display”).

    In my university days on the 1 or 2 exams that allowed calculators, the rules were “calculator – no QWERTY keyboard”.

  16. First calculator: Sinclair Scientific in 1975! But aged 8 I couldn’t figure it out so we took it back and replaced it with a Commodore 796M (it still works)! I used it to experiment with maths.

    For secondary school I persuaded my parents to buy me a Casio fx-180p (programmable) which served me well until a school mate broke it one lunchtime, so I bought a Sharp EL-531D (had hyperbolics, but otherwise characterless) before finally finding the wonderful Casio fx-4000p! The greatest pre-graphic Casio (apart from the legendary Fx-602p). Disappointingly it was lost/stolen at Uni, but a few years ago I bought another on eBay!

    Wonderful, wonderful Casio fx-4000p!

  17. “For the average person, they replaced the need to learn multiplication tables, necessary for working out how much a dozen apples would cost at $0.05 an apple.”

    Some might argue that’s not a blessing.

  18. Very good article.

    I also am part of the trailing edge of the tables and slide rule generation. My first calculator was a Radio Shack basic arithmetic plus square root and a memory unit..I still have it somewhere. Kept for the good quality keypad and case rather than the electronics. I sat with a pad of paper and mapped out the state machine and found a feature or two that were not documented in the manual.

    Now I use a pair of Casio fx-115Ws. Despite their being programmable, I never use that. If I want a program I’ll use a computer.

    When they were selling off slide rules I picked up a top of the line Post and Pickett for $3-4 each. Someday I’ll mount them in a glass frame with a little hammer and “In case of battery failure, break glass” painted on the glass..

  19. I’ve got a Canon Pocketronic in my collection… Also about 100+ models, ranging from massive desktop models with resistor-diode logic, to pocket and handheld models, all varying from 4 bangers to fully programable, scientific, and graphing models. I’ve got stuff ranging from the early 1960s such as parts, like the nixie display/decade counter boards from a 1961 Anita Mk7 and a non working Wang 360SE, to a 1965 Friden EC-132, and a similarly aged Cogito 240 SR, all the way to relatively modern models, like the TI-89. I have a couple TI-30s… Those things came bundled with other calculators I picked up! They were POPULAR! XD

  20. I was on holiday in Malaysia, and was making mistakes with the exchange rate all the time. But didn’t have a calculator with me. So I finally went to a store where I saw a tiny calculator for about $5. Haggled really hard and got the price down to $2.50. It was branded with some 1998 football event logo, so I’m sure the owner got it for free somewhere. :P

    But my HP-16C is actually the calculator that gets the most use. My dad got it from his work, and it got into my hands when I started studying computer engineering. Invaluable features, like the variable word length, and/or/xor/shift operations, hex/dec/oct/bin conversions, programmable, reverse polish notation. And extremely durable too! At one point in it’s life the dog got to it and chewed on it. It gained a few scratches, even one on the LCD protection glass, but everything still works up to today. I still use it a few times per week, always have it close by. And I even ported the HP-16C simulator to my iPhone. (but nothing beats real buttons). This is the one calculator that will probably play a big role throughout my whole life. Hopefully it will continue working for the next 50 years or so.

    1. I also have a Casio Casio FX-9750 graphing calculator. I thought that it’s versatility would be useful for me. But man, is it complicated to use… I learned from it to avoid calculators with manuals that are bigger than the calculator itself. :) Although, I have to say that I’m amazed at the price that Casio can produce these machines. I’m a huge, huge Casio fan!

  21. I remember the first calculator I ever saw, it was ’71 or ’72, John spent $100 on it (an outrageous sum for the times) and it would do square roots at the touch of a button! Amazing!

  22. Calculators got me started in computing and electronics. In my early teens I discovered I was within biking distance of the UK Commodore factory, and a Saturday morning spent bin diving in their skips out back would result in enough reject parts to make functional calculators.

    The best I managed was an SR4190R 90 function scientific, which caused some eye bulging from visiting teachers when a spotty 13 year old pulled one from his pocket to solve the problem that they had given him.

  23. I kept My HP48G for more than 20 years, but finally killed it while trying to fix a faulty LCD zebra strip. It’s really a shame that you can’t disassemble it without physically damaging it. It now lives as an emulator on my Android phone.

    Fun fact : the memory was kept intact for 15 years on the same AAA battery set by putting the calculator in “deep-sleep” mode (SPC+ON). It kept my sys-rpl programs and some variables that I long forgot about into its RAM. I only had to change the batteries because they leaked and ate away the contacts :/

  24. I most often use Sage as my calculator now because I always have it running on a rpi in my home. Occaisonaly bc.

    I still have use for my Casio “scientific calculator” which is useful on the go and for numerical calculus if I just want an answer fast-ish.

  25. In college one of the assignments was to build a simple calculator from discrete components. It was a great exercise and I found it very humbling when I was faced with the challenge of understanding fundamentals. It is surprising what we take for granted.

  26. I still keep my TI-85 by my desk for the occasional quick calculations. Unfortunately, its memory has long since been lost, as it would have some of my very first programs. Back in high school, I found a website with instructions on how to overclock it by swapping out one of the caps. I don’t think I quite realized how risky it was, and how likely I was to brick my parents’ investment in my education, but I managed to get a nice little turbo switch soldered in and hot glued in the back. Showing off how my calculator was 2.5 times faster than my friends’ was my geeky pride and joy in high school :-)

    I also went to nerd camp one summer and discovered the other kids had z-shell with the really good games, and the only way to transfer it was to clone the entire calculator memory over. Of course, I did it in a minute, and quickly shared it with all of my friends back at school where it spread like wildfire. By the time I was graduating, I could look in just about anybody’s calculator and see a couple of the shared variables that showed that their calculator’s memory was descended from mine! I was patient 0 in bringing handheld games to my school, and probably responsible for a corresponding grade drop across the board.

  27. I’ve been teaching college chemistry since 1979 and I’ve seen an emerging serious problem with calculators. When they first came out, they were wonderful devices for cutting down on problem-solving time. But most of the people using them were conversant with basic mathematics. When a chemistry student worked a problem and got a calculator answer such as 1.3×10^-21 atoms, usually they could recognize that that was an impossible answer; wrong magnitude.

    Over the last six semesters, over 49% of my (majors-level) general chemistry students dropped, failed, earned an (unsatisfactory) D, or changed from credit to audit to avoid failure/dropping the course. If their examinations (and math ACT/SAT scores) are any indication, a lack of awareness of simple arithmetic is at least a significant part of the problem. A student will often accept the calculator answer without considering whether that answer makes sense; the calculator has changed from a tool to a tin god. I’ve left gen chem students befuddled when I ask them “Okay, what’s 1800 divided by 10?” or “What’s 4 times 7?” or “what happens to the result when the denominator is increased?”—those are actual examples. Estimating an answer’s magnitude? Forget it, that’s right out.

    These students are planning (hoping) to become physicians, veterinarians, pharmacists, etc. What will happen when a physician needs a calculator to determine whether that dose of medication is sufficient or lethal?…I see the potential for some very serious problems ahead.

    1. It was a great “Ride” being part of that age, “From the Slide Rule” to the Programable Calc’s. I especially identified with the HP line of hand helds. Still own/use numerous HP 41 CV/CX’s, and 15C’s. Too, I’m baffled the Apple seems to reject they’re use (Simulators/Emulators on the MacBook Pro’s. (Verses Windows Acceptance of their use) Example the RPNcalc-15c the one offered as an emulator, does not recognize the full memory bank as the true 15c, or for that matter the 41 series Calc allowing only 10 key storage, whereas the orig hardware allowed 2 key entry and more: that is… The mac versions allow only 0 the 9 (key) verses the robust 2 stroke storage such limitations (example) single key 4 versus 44, up-to 99 storage capacity, not to mention the other plethora memory registers, needed for “programming” that most of the high end “HP hand held” can/could do. I could be wrong as/or perhaps there is a full function HP calc emulator/simulator out there that will work on the mac platform? That would be especially cool.. Keith

  28. I had a Ti-30 as first calculator in school. The teachers recommended it. But it soon developed bouncing keys. Later a Sharp (don’t know the type any more) with several (not understood at that time by me) statistical functions and such stuff, but not programmable.
    At the university I got a HP-28S(X) which I sold later to a colleague to be able to purchase one of the HP-48 series (SX?). Which I still have, but it sits in a drawer without batteries. The emulator on the phone is so much more convenient – no extra device necessary. But mostly I use the Excalibur 32 RPN calculator on the screen. Or Excel or LTspice :-)

  29. I have a Casio CM-100 which I use about once a week. A very rare calculator, I believe, given that there seems to be very few of them about.
    I got it in the early 80s from a friend who worked for Casio in London, and up until the mid 90s I’d only ever seen one other (a work colleague who bought it in the Channel Islands).
    There is (was?) one on Ebay with a price tag of $778 (yowser!) … I think I paid £12 (< $20).
    I think the 'CM' part of the model is for 'computer math', and it came my way because I was a programmer.

  30. In 1972 while stationed overseas in the US Air Force I purchased a Panasonic calculator for $88. The calculator had four functions, a square root key and used six AA batteries. After the warranty expired I opened the calculator and it had a Texas Instrument integrated circuit for it’s brain.
    When I returned to the US, I gave the calculator to my father because he was color blind and able to see the green vacuum florescent display but unable to see the red led displays used in many other calculators popular at the time.

  31. I started work as a mass properties engineer at a rocket motor company in late 1979. The new project that I was hired for was not quite ready for me when I arrived so I was given some “busy” work for the first day or two. Somebody gave me a drawing of a rocket motor component that had somewhat complicated geometry. They asked for the weight, C.G. and inertia (all three axis). The company had TSO’s at the time but I had not been given one yet. After a couple of hours, the engineer came back to my desk to see how I was doing on the task. He saw a paper on my desk with all of the numbers written on it. He garbed the paper, looked at the numbers, and exclaimed, “Who gave you this?” I told him “Nobody, I just worked it out on my HP29C calculator.” He picked my calculator up, looked at it, put it back down, and said, “Huh” as he turned around and walked away. I latter learned that it was this man who had wrote the M.P. FORTRAN code for the TSO’s. Jim

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