Babbage Lives, A New Beginning

Hello happy readers,

OK, I think I’m caught up with my post–conference duties so I can give you a taste of the Museum of Computing’s Babbage show I was babbling about…However, before I jump into that, I wanted to give you a heads up on the new $3.3k Sennheiser MKH 800 Twin, which offers a dual capsules design. The kewel thing is that signals from both transducers are available separately as individual channels at the microphone output, allowing remote adjustment of the mic’s pickup pattern…Not novel but very useful!

OK, on to that loverly difference engine…Let’s start w/a pic:

A Babbage Difference Engine

As you can see, it’s big; damn big. According to the Museum of Computing, it “…was completed in London in 2002, 153 years after it was designed. Difference Engine No. 2, built faithfully to the original drawings, consists of 8,000 parts, weighs five tons, and measures 11 feet long.” When it runs, it sounds like a combination of a small printing press and powered loom. It actually is a printing press, since it does provide hot metal, hard copy output of its calculations. If you don’t know what I mean by “hot metal,” check this out…

It’s not surprising that it sounds like a powered loom, in that both machines have a great deal in common. Starting in the early 19th C. and still in use today, automated “Jacquard” looms used punch cards to “program” the design of the desired fabric. A clever fellow named Herman Hollerith, working for the US govt., combined the punch card and some electrical gadgetry into a semi–automatic electro–mechanical tabulator used to process data for the 1880 US census.

Anyway, here’s a side view of the cogged vertical rods, the “carrying towers,” that do much of the calculating:

Side view of Difference Engine #2

Speaking of calculating, this beast solves 7th order polynomials. Not bad for a large bucket of bolts. Here’s a rough composite of the carrying towers:

Carrying Towers

Although this machine is mainly true to the original design, the drive mechanism has been modified to improve handling characteristics. Seems that the original design made it quite a PITA to drive. Here’s a detail of the crank that powers the beast:

Drive Crank

Those large stacked horizontal plate–like components are cams that provide most of the control logic. If you grab the handle and crank, you have to maintain a particular cadence and speed so as not to under or over–clock the machine and jam it…humm, some things never change.

Though the steampunk intricacy of the Difference Engine is wonderful to look when static, in motion it’s a thing of beauty.

Clocking the computer

For a card carrying geek, my trip to the South Bay was worth every drop of petrol. If you head over to the Museum’s site, you can watch a movie and read more. Speaking of steampunk, head to your library or Amazon and pick up a copy of Gibson & Stirling’s The Difference Engine, the prototype for the entire genre and well worth the effort.

The Difference Engine (Spectra Special Editions)

If you’re as caught up in this as I’ve been, you may also want to read about it from the viewpoint of Doron Swade, the guy who was wacky enough to actually build Engine No. 2.

The Difference Engine: Charles Babbage and the Quest to Build the First Computer

I have more steampunk stuff lying around somewhere to tell you about but I’ve gotta get back to work! TTFN…

One Response to “Babbage Lives, A New Beginning”

  1. Excellent Information thanks for sharing.