old IBM calculator

Today, I briefly attended an Earthwatch conference at the Harvard Science Center. It wasn't as good as it could have been, but what was interesting was the IBM Automatic Sequence-Controlled Calculator, Mark I. This was apparently used by Harvard since 1946 or so. Now, it's in the lobby, or at least most of it. It's an electromechanical machine, no electronic components. Very fun to look at! The plaque said that in modern terms, it would have been 52 Hz and 1.7K RAM. It has one constant panel (dozens of rotary switches), an enormous array of relays, a missing multiplication module, a paper tape module (for output), a paper tape sequencer module (input), two typewriters (input and output), and a punched card device. It was shut off, except for flourescent lights, but I bet it could probably run...it was about 2 m tall and less than 1 m deep. The photos showed that it originally had a lot of pulleys on the back for dealing with paper tape. It is driven by a motor shaft that extends through the whole machine, spinning at 4 rpm. This acted as a clock and drove the tape mechanisms. Seems very easy to use, with proper instructions. I wouldn't mind having this in a hypothetical basement. On the plaque, it says it was used for ray tracing for lens design. Just thought someone would like to know :) ______________________________________________________ Get Your Private, Free Email at http://www.hotmail.com