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Comment by greymalik | Hacker News Reader

When the book “builds” a computer, I’m assuming that’s a virtual computer? If so, what language does it use?

If you're actually looking for something that does build to a virtual computer, Nand2Tetris (second edition of the book The Elements of Computing Systems that goes with it is now out) is a great companion to Code: https://www.nand2tetris.org/.

Code is more high level, Nand2Tetris and Elements is project based but covers some similar territory.

I was actually asking about The Elements of Computing Systems in my comment, not Code. What language does it use to build a virtual computer?

The hardware exercises expect you to use a simple HDL, you write an assembler in your language of choice (I used Ruby, but others have used Python or JavaScript), and you write programs for the computer you "built" in earlier chapters using Jack (a language with Java-like syntax).

I wrote mine in awk :)

You program in HDL using the Nand2Tetris software suite [1]. Super fun - I went through the book on my vacation last year. Highly recommended.

[1] https://www.nand2tetris.org/software

Quoted from the 2021 edition:

"Project 4 is written in the computer’s assembly language, and projects 9 and 12 (a simple computer game and a basic operating system) are written in Jack—the Java-like high-level language for which we build a compiler in chapters 10 and 11."

Nand2tetris uses its own version of Hardware Description Language (HDL). You will also write a compiler for it's own language called Hack.

Code is not more high level it starts from as low as you can get in terms of abstractions, it explains what electricity is and how it moves through wires and and moves on to creating simple logic gates using switches.

Highly recommend Nand2Tetris. I completed it a few months ago as a relatively non-technical person (I had only taken CS50 as my first CS class ever in 2020) and learned a ton.

GP said “builds up to.” It’s more about the abstractions adding up so that the reader understands how electrons can be programmed. There is no implementation of any kind of virtual or hardware machine in the book.

He goes: electricity, relays, logic gates, circuits (like adders), CPU, RAM …

It’s been awhile so I might have missed a step or two. You’ll come away knowing how we used electricity to get from lightning bolts, to pocket computers. You will not come away with a programmable machine.

It’s more a book that actually shows you how a computer really works, from first principles.

It’s not a book about implementing a particular computer - it’s more about giving you the rough thought process about how it actually works at the level of electricity and wires, and how this gets built up into something that actually calculates stuff.

It’s the first book that took me from “computers are mystical magic” to “computers are understandable magic”.

There is a much older text book called the Art of Digital Design. In it, if you buy and solder the necessary components, you get a fully working PDP-8.

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