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> a nand gate is not too primitive, of course, but building an actual cpu out of nand gates involves several hundred of them, and that circuit is harder to describe than a universal turing machine

Building a CPU with a Turing machine would also be quite complex. Probably less complex, but only because logical circuits are more primitive.

> turing's original paper gave a convincing argument that turing machines were universal; he said that they could do anything a mathematician could do, since the mathematician can only hold a finite number of symbols from a finite set in his memory at once, and can only fit a finite set of symbols from a finite set on a page in his field of view. so the squares on the turing-machine tape were originally pages in a notebook

Yet according to mainstream theoretical computer science (professors), you didn't mention the allegedly relevant property of Turing machines: That the tape is infinitely long. Otherwise it is considered to be equivalent to a mere finite-state machine. Which is, of course, absurd. I think the main difference between FSMs and Turing machines (or logic circuits with delay) is that the latter allow for some sort of "memory", which is (I would guess) a special type of state that finite-state machines don't support.




mostly your comment is wrong from beginning to end

it is important for novices reading this thread to know not to treat it as useful information




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