Happy Birthday, HP 12c—35 Years and Counting

Last year was the 50th anniversary of Moore's Law. One consequence of Moore's Law has been that computers got significantly faster on a regular basis. Until comparatively recently, when computers by and large were all "fast enough", we would all replace our computers and smartphones every couple of years. The idea that an electronic product even 10 years old would still be on sale seems almost comical. The original iPhone launched in 2007, only 9 years ago. And we have been through 7 or so versions since.

In fact, there is a product that first went on sale exactly 35 years ago today, and has been on sale ever since. It is the Hewlett-Packard HP12C financial calculator. You can still buy it on the HP website for $69.99. If you are reading this blog you probably have some idea of the cost of semiconductors, and the cost of keyboards. I can't believe it costs more than $5 (or for sure $10) to make.

I don't know of any other electronic product that is 35 years old and is still on the market. It went on sale on September 1, 1981 at a price of $150 (about $400 in 2016 dollars). However, it is still considered a state of the art product for financial professional and related areas such as real estate. Somewhat more surprising, it was the first calculator that used reverse-Polish-notation or RPN (I assume it is not named directly after the inventor, Jan Łukasiewicz because nobody had a clue how to pronounce his name). Once you are used to RPN, it seems quite natural, but I am surprised it wasn't a major barrier to adoption. In an interview with CNET on the product's 30th anniversary, Dennis Harms, the original project manager, said RPN:

...improves user input efficiency. For example, to get the total of 4 plus 6, you just have to type in "4 [enter] 6 [enter] +", instead of having to use the equal sign. This cuts down the time a user has to work on the keypad.

Well, since on a regular calculator, you would just type "4 + 6 =" which is one keystroke less, it's not a very convincing argument. Where RPN really comes into its own is on more complex calculations since you don't need to (and can't) use parentheses.

It turns out the HP 12C was one of the first products to use CMOS chips. In 1981, CMOS had not yet gone mainstream, most semiconductors were still built in NMOS. There were three chips: the processor, R2D2, the RAM-ROM-display-driver chip, and a real-time clock. As a result, the watch battery that runs it only needed to be changed every few years.

Harms told CNET it was an unexpected overnight success:

The product was first ordered by college bookstores. At the time, because of the common lag between ordering and production, retailers tended to order about four times the number of products they expected to sell immediately. The bookstores ordered 4 million units of the HP 12c, expecting to sell just 1 million. To everyone's surprise, everything sold out at launch.

Of course, like any electronic product, it was only expected to last a few years before it would be superseded by something better. But it was such a perfect match for what financial professionals needed that it has never stopped selling. The internals have been changed over the years. Apparently it now uses an Atmel chip containing an ARM Cortex-M4 processor that runs an emulation of the original proprietary processor.

As HP describes it:

A time-tested performer, the HP 12c has an easy-to-use layout, one-line LCD display and efficient RPN data entry. Easily calculate loan payments, interest rates and conversions, standard deviation, percent, TVM, NPV, IRR, cash flows, bonds and more. Over 120 built-in functions. Ideal for real estate, finance, accounting, economics, and business work. Permitted for use on the CFP and CFA Certification Exams, and GARP FRM Exam.

Happy birthday, HP 12c!

Next: RISC-V Gathering Momentum

Previous: MIPI Soundwire