[cctalk] Re: the 1968 how to build a working digital computer

Steve You ask a lot of good questions. The story is pretty well documented. There was a company that made a commercial version of the computer described in the book https://blog.adafruit.com/2013/05/08/how-to-build-a-working-digital-compute… There is a nice paperclip computer at the System Source museum in Hunt Valley, MD. I am sure there are people who actually built homebrew versions by following the book but I have never seen one. Analog computers are not like quantum computers enough for a valid comparison. Different era, different uses. Quantum computers are still digital computers and they're really nothing like analog computers of the 50's-late 60's. Analog computers were wired to complete a circuit that performs a mathematical function circuit. The inputs and outputs are voltages or other electronically-measurable forces such as vibration. When an analog computer program runs the output is sent to a voltmeter, oscilloscope, plotter or counter, or custom device. A person would take the plot (waves, plotted points, etc.) and measure the slope or wave frequency manually by performing additional calculations with a slide rule or feeding the data into a digital computer for analysis. Think smart programmable thermostat. Analog computers are more like open-use peripherals that can be programmed to do one thing at a time over and over. Analog computers often had amplifier tubes which were used to generate input voltage pulses to be fed into the program circuitry. I am just touching the surface, but hope that explains what they did. They're no longer used for general computing because now we have USB devices that do analog to digital conversion 50's-60s' analog computer programming is done by patch panel. BIll On Fri, Jul 19, 2024 at 10:58 PM Steve Lewis via cctalk < cctalk(a)classiccmp.org&gt; wrote: