Retrotechtacular: Donner 3500 portable analog computer

retrotechtacular-donner3500

What if we told you we had a computer you can take with you? What if it only weighed 28 pounds? This is a pretty hard sell when today you can get a 1.5 GHz quad-core processor packing computer to carry in your pocket which weighs less than 5 ounces. But back in the day the Donner 3500 was something to raise an eyebrow at, especially for tinkerers like us.

The machine was unveiled in 1959 as an analog computer. Instead of accepting programs via a terminal, or punch cards, it worked more like a breadboard. The top of the case features a grid of connectors (they look like banana plugs to us but we’re not sure). The kit came with components which the user could plug into the top to make the machine function (or compute) in different ways.

We’re skeptical as to how portable this actually was. It used vacuum tubes which are not fans of being jostled. Still, coming during the days when most computers were taking up entire buildings we guess the marketing claim holds up. If you’d like to see a bit more about the machine’s internals check out this forum post.