It still is more low level than any other language currently (that can be run on multiple architectures) which I think is what the OP was saying. If you compile C without compiler optimizations, it will generate code that is exactly what you wrote. The argument the paper makes is that the instructions available in modern processors and the way we use them to optimize code (such as instruction level parallelism) is a consequence of C being so important despite being made for much older and much simpler machines. Because if the generated binaries from any C compiler without optimizations isn't low level then you might as well say the same about x86 assembly, and then you're basically out of options.
But it's not. It has become a high level language. The idea that C is still a low level language is no longer true. It is highly abstracted from modern hardware.
Edit: I just saw your edited comment. Yeah the point is you really don't need to know much about the hardware to write C. It doesn't force you to understand what's actually going on behind the scenes.
My take is both C and the hardware are targeting the same abstract machine. It seems too that attempts shift things one direction or another haven't been successful. Itainium which tries to force the compiler to deal with instruction scheduling and parallelism, failed. Things like LISP machines also didn't do well.
So thinking in terms of the abstract machine are valid for now. The exceptions mostly have to do with caching and understanding that processor can and does execute short sequences of instructions in parallel.
Yeah sorry about the ninja edit. Very often I reply to a comment without actually finishing and then edit it. I thought Hacker News was delaying my comments by 1 minute though according to my configs? Anyways, I agree that you don't really need a deep understanding of the hardware nowadays to write C, but my point is that it's still useful to learn because you still need more understanding of the hardware than you need to write something such as Ruby.
The point the OP was making is that it still forces you to learn more about the hardware than other languages. Arguably, it also forces you to learn more about the software itself with things being much more explicit than in a modern complex language such as Rust. I'm also just not aware of _any_ language that actually maps well to what the CPU is doing nowadays since they are such complex pieces of silicon.
But does it really force you to learn more about the hardware versus other languages? I am challenging that assumption or belief.
C has memory pointers, but those are pointers in a flat memory space abstracted over the physical memory hierarchy.
So yes, you do need to understand that the hardware has memory addresses and that pointers can reference memory addresses. Aside from that I don't see much difference to Java or Python in terms of requiring a deeper understanding. Even Python has bitwise operators.
