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Show HN: I made a programmable computer from NAND gates

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Re: Show HN: I made a programmable computer from NAND gates

#31

This is amazing work. I wanted to build something similar (virtual) while I was taking the Nand2Tetris course. I'm so impressed that you actually did it. You must have a really good understanding of how computers work now.

And I was just thinking about the same thing this morning, using SVG to model the basic components. And lo and behold somebody has done a magnitude more amazing job then what I was imagining!

Re: Show HN: I made a programmable computer from NAND gates

#32

Wow, seriously impressive. And the fact that this is the work of basically a high-schooler. I fear for the kind of competition my kids will have just to make it to college.

This is a natural extension/expansion of the “NAND to Tetris” course on coursera, and is free if you don’t want to be graded.

The course walks you through it all, and there is an accompanying book that you do not need to buy to finish the course.

Anyone who wants to do this and can focus on it for enough time can complete it and extend it into whatever shape they like, like this person.

It really is a good course.

Re: Show HN: I made a programmable computer from NAND gates

#33

Wow, seriously impressive. And the fact that this is the work of basically a high-schooler. I fear for the kind of competition my kids will have just to make it to college.

This is a natural extension/expansion of the “NAND to Tetris” course on coursera, and is free if you don’t want to be graded. The course walks you through it all, and there is an accompanying book that you do not need to buy to finish the course. Anyone who wants to do this and can focus on it for enough time can complete it and extend it into whatever shape they like, like this person. It really is a good course.

Absolutely true, I'm working my way through it now; it's challenging and time consuming, totally worthwhile imo.

Re: Show HN: I made a programmable computer from NAND gates

#34
post #25

Cool project. It reminds me of a theoretical issue. As the project page says, this system is clearly Turing equivalent. Since it runs software, it even implements a _universal_ Turing machine. But the design uses only (synchronic) sequential logic [1] and Wikipedia seems to suggest that automata theory considers sequential logic only equivalent to finite state machines. Not Turing machines. Isn't that clearly a major…

Real-world computers are equivalent to linear bounded automata, not true Turing machines, because they have finite memory. This technicality is mostly ignored because a computer with a large finite memory is a decent enough approximation to a Turing machine for practical purposes. But, for example, the halting problem is decidable for linear bounded automata — because there are only finitely many states, every computation must either halt or eventually revisit an earlier state and get stuck in a loop — so in theory it’s an important distinction.

Re: Show HN: I made a programmable computer from NAND gates

#35

Wow, seriously impressive. And the fact that this is the work of basically a high-schooler. I fear for the kind of competition my kids will have just to make it to college.

This is a natural extension/expansion of the “NAND to Tetris” course on coursera, and is free if you don’t want to be graded. The course walks you through it all, and there is an accompanying book that you do not need to buy to finish the course. Anyone who wants to do this and can focus on it for enough time can complete it and extend it into whatever shape they like, like this person. It really is a good course.

I primarily used the physical book to learn about the nand2tetris platform. I highly recommend it, it's an enthralling read

Re: Show HN: I made a programmable computer from NAND gates

#37
Doing a design for this (specifically, design a microcoded, pipelined RISC processor, from the bottom up, with nothing but NAND gates) was the main problem on the Computer Hardware quals exam at UC Berkeley in the early 1990s. We didn't have to physically build it, though, just produce the detailed design on paper.
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