The Antikythera Mechanism — Again

Antikythera Mechanism, fragment A, "front"

All of you are surely familiar by now with the Antikythera mechanism, an ancient Greek device for computing a variety of astronomical and calendar-related events, fragments of which were discovered in a shipwreck from Roman times about one to two centuries BCE, fragments found in modern times by sponge divers in 1901. For at least a century, scholars, scientists, mathematicians and inventors have X-rayed the device, speculated on its function and age, built physical conjectural models of the device (including a bit of whimsy made of Legos, to go with your Lego harpsichord I suppose), and built mathematical models of its operation.

By now the device is mostly understood, and the results are astonishing. If you have ever read anything about Archimedes (d. 212 BCE, killed as he worked, run through by a Roman soldier), you have some idea of the genius afoot in Greece in the era in which the Antikythera mechanism was built.

Thanks to ellroon, we have an article by George Dvorsky at io9 and in turn a NYT article by John Markoff, and finally a suite of YouTube videos, starting here with one about the Lego Antikythera model, followed immediately by a longish show (Nova??) about the device itself. The two videos (there are more, but I stopped after two) are well worth watching.

Enjoy!

Open Software: What You Get For Free And What You Don't

The First Computer Bug

Back in 1947, a year before I was born, when early computer wizard Rear Admiral Grace Hopper (USN) found a moth fouling a relay in the Harvard Mark II electromechanical computer, she removed the moth and taped it in the project log book, where I presume it is still preserved for posterity. In other words, it's not my fault: computer bugs have been around quite literally all my life. I'll be polite and not speculate on what Adm. Hopper said when the bug got into the relay; I assume that since she was Navy, she knew how to curse.

Geany

Tcl/Tk

Fast-forward (now there's an increasingly antiquated term!) to 2013, where I am in the middle of my n'th attempt to become even minimally competent at programming for a *nix (i.e., UNIX or Linux) system, n being a regrettably large integer. With great deliberation over each choice, I have chosen to learn the programming language Python (yes, it's named after Monty Python), the lightweight integrated development environment Geany (perhaps the only piece of developer software with which I've felt instantly comfortable; on the n-1'th attempt I used Eclipse on an old, slow machine and came to regret it), the graphical interface library Tcl/Tk (also known for historical reasons as Tkinter) and the visual form design tool PAGE. I don't know how common these things are out in the real world of *nix because I never had a contract in that world; I just have to start somewhere.

Things went swimmingly up to a point. I managed to construct manually a few simple programs using Tcl/Tk, tapping the code by hand, copy-pasting bits and pieces from examples provided by other people. That all worked pretty well.

Then, after the aforementioned deliberation, I set out to install PAGE. The author of PAGE claims it rests on version 8.5.4 (or newer) of Tcl/Tk. The version installed on this box by the original Ubuntu installation is 8.5.11, so I should have been OK.

I installed PAGE with no significant error messages, I attempted to run it from a command prompt. It quit with a complaint (presumably from the Python runtime) that the program (i.e., PAGE) was attempting to use calls to Tcl/Tk version 8.6, the latest version... NOT 8.5.4, as advertised in the documentation. Thus entered the dark side of free software.

ActiveState, one of the major commercial software and support companies in the Tcl/Tk world, offers a prebuilt freebie version 8.6 package of Tcl/Tk, with no support. I can see the advantages of their doing so: programmers that grow up using the freebie version could very likely influence the subsequent purchase of commercial licenses by their employers or clients. Freebies are pretty much traditional in the Linux world, and the market of people who use them would be a good market to tap into.

I downloaded the Tcl/Tk 8.6 freebie package and attempted to install it... three times, using three different install tools. I got hundreds of error messages, which I could not redirect to a file (due to my ignorance, I'm sure). I ran a few of the handmade programs using 8.5.11 to make sure I hadn't destroyed that; apparently it's OK. But after an entire evening of my life spent on this project, I am back to square one. Even for a guy who used to do this stuff for a living, that's pretty frustrating.

And like Adm. "Amazing" Grace, I know how to curse!

Steampunk Economics!

MONIAC, Bill Phillips
(via Timothy Taylor)

Via Paul Krugman, we have Timothy Taylor talking about an hydraulic analog computer, MONIAC, built in or before 1949 by Bill Phillips (of "Phillips curve" renown), intended to model an economy in the presence of user-specified changes to fiscal and monetary variables. Taylor in turn points us to information about an even earlier economic hydraulic analog computer built by Irving Fisher in 1891. (No, I did not transpose a digit: I mean 1891.)

Technophiles and lovers of steampunk will appreciate these devices for their own sake; I, at least, am reminded once again, not for the first time, that there was effective practical mechanical computing of very complex functions of many variables long before there were digital computers of any sort. Economists and similar researchers may learn from the existence of these machines that, as Krugman emphasizes, it is important always to have a model, in the broadest definition of the word, of any system about which one proposes to argue: the lack of a model inevitably leads to certain types of errors that the very process of building a model (physical or mathematical) forces one to deal with a priori. I don't know economics very well, but I can attest to the truth of Prof. Krugman's statement in other contexts: modeling is essential to larger problem-solving.