Earlier this month I had an opportunity to tour The Computer History Museum in Mountain View.

For the next couple of months they have a wonderful exhibit on display- Charles Babbage's Difference Engine Number 2.
The story behind the machine is fascinating!
* Conceived long before machine calculation became standard
* Designed to be robust and exact
* Never built(!) until the original blueprints were donated to the London Science Museum not even two decades ago
* This second copy is on it's way to its Seattle owner.

My time at the museum was brief, however, and I'm interested in another visit.
Admission is free and the tours are very well done.

Anyone up for it?
Suggested dates?

The Difference Engine was there when I visited, last autumn... I don't know when I'll next be in California, but I just wanted to confirm, to anyone maybe thinking about going, that seeing it in operation was completely awesome. It felt like being an ape at the foot of the monolith in "2001".

(And when someone asked the operators how the eight coefficients of the polynomial to evaluate were themselves determined, the answer was "Not sure... probably they just found the first eight terms of the Taylor expansion" and everybody nodded sagely. That was when I knew I was amongst real geeks.)

Peter

Gee, I wonder who that could be.

The museum is located less than two miles by bicycle trail from where I am living. I saw it two days ago when I bicycled past it on my way to the Honda dealer in Palo Alto. (An eight mile (each way) ride to get the two license plate attachment bolts they neglected to provide with the new car. Sure, I could have gone down the block to the hardware store, but "...where's the fun in that?")

If anybody goes to see it, I will be mortally offended if they don't stop by and say hello!

tanstaafl.

I've seen the one they have in London, amazing bit of kit and well worth a visit.

Unfortunately when I visited it wasn't running, but I was amazed how close we could get to it.

Cheers

Cris.

Edit - This reminded me that I read a very good book on the making of this machine. If you can find it well worth the read.

Not who you think it is....

Amazon has dozens of copies, used and new, starting at 16 cents plus $3.99 shipping. I bought a new one for $1.92 (plus shipping).

I visited the museum this afternoon, will go back tomorrow at 2 pm for the Babbage tour. Here's a photo I took of it. The workmanship in that machine is simply fantastic.

tanstaafl.

Even more fantastic- I heard that they introduced 'error' into the fabrication of the parts in order to replicate the standard of precision available at the time. Obviously, our new machines and materials are far better and more consistent than what was possible in the mid 1800's.
Even with the addition of random tolerance issues, the machine *still* works flawlessly.

That book should be a fun read!

Actually, It was supposed to go together flawlessly. There were problems with fabrication.

It took a lot of tinkering to get everything meshing properly.

Edit: the mention of "Victorian Requirements" is more of a nod to the exacting requirements for it to be beautifully made, in addition to being functional.