It’s been established that a question can be on-topic
on multiple Stack Exchange sites simultaneously.
Jeff’s answer here focuses on whether certain questions are
on-topic at Stack Overflow, which is not what this question asks.
Gilles’s answer to What is the current consensus
on programming questions? does not, in my interpretation,
really support Jeff’s answer here.
Power users tend to have a working knowledge of some low-level interfaces
(through strace, by reading source code that they half-understand
to understand why a program is behaving [sic], …),
so questions involving these are also ok here.
Questions requiring serious knowledge of an “advanced” programming language
(pointers in C, objects in Perl, etc.) are off-topic.
This (meta-)question (i.e., Margaret Bloom’s question)
mentions “a question about MMIO remapping for the devices
behind a node’s local PCIe interface on a NUMA system.”
This seems to fall under Gilles’s category of “reading source code …
to understand … a program …”
and not “serious knowledge of an ‘advanced’ programming language
(pointers in C, …)”.
Therefore, I believe that the answer to Margaret Bloom’s question is
“yes, questions about the behavior / functionality of Linux
are on-topic at U&L.”
And I believe that Gilles’s answer supports this position.
FWIW, I had this exchange with bwDraco four years ago:
Is there a SE site on the Linux Kernel?
Do questions about the Linux kernel get answered on Stack Overflow? – G-Man
@G-Man: Unix & Linux – bwDraco
I can’t see it now, because it’s been deleted,
but I had the foresight to bookmark it and keep a copy.
10K users (on Super User) should be able to verify it.
I’ve been bothered by Tim Post’s answer
to Are questions about the internals of the Linux kernel
on-topic for Stack Overflow?
(again, not the same as what Margaret Bloom is asking)
ever since I first saw it.
Sure, “Would it take a programmer to understand answers to this?”
(or even to understand the question itself) is highly relevant.
But imagine this hypothetical dialog:
I have cataracts and need eye surgery.
Who should I get to do it?
Well, a surgeon, of course.
Sure, if your choices are an auto mechanic, a surgeon,
taxi Uber driver, you should choose the surgeon.
But, if your choices include a brain surgeon, an eye surgeon
(ophthalmologist), and a heart surgeon, you should pick the eye surgeon.
By the same token, “Would it take a Unix system programmer
to address this question?” is equally or more important.
I don’t spend a lot of time at SO, but a glance at their tags page
— and, yes, C++ and C#.
C comes in as the 16th tag.
I don’t know how many SO users are going to be able
to understand a question about a device driver, memory-mapped I/O,
or other kernel code, but it seems like there are going to be
a lot of people there who will be unable to answer such a question.
Logically, we should have the highest concentration of Unix experts
here at U&L, and so I believe that
questions about details of how Unix behaves are on-topic at U&L.
if we don’t have the highest concentration of Unix experts here at U&L,
that may be because they feel like they’re not wanted here,
because questions in their wheelhouse keep getting kicked out.
And, IMHO, that would be a shame.
If Stack Overflow has lots of Unix system programmers, that’s great.
But we should encourage such experts to spend time in U&L
by allowing questions about the behavior / functionality
of Unix & Linux on the U&L site, no matter how low-level they are.
(Of course questions that are about programming,
like “What’s the difference between
++i?”, are off-topic here.)