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The benefit of building the Difference Engine today, according to the TED Talk about Babbage.
What is being able to 'see' and understand how a computer works -- any computer?
TED Talk:
["In fact, it was capable of doing everything we do today with computers, only really slowly."]
["When it's built, you'll finally be able to understand how a computer works, because rather than having a tiny chip in front of you, you've got to look at this humongous thing and say, 'Ah, I see the memory operating, I see the CPU operating, I hear it operating. I probably smell it operating.']