I think we are saying the same thing. By disk, i meant disk I/O which is the main practical purpose of the tool. Of course, Linux being Unix, a raw disk is a file, so is /dev/null.

Of course a file can be everything, which is a kind of the point of Linux. But that doesn't change the fact that 'dd' is for disk (or file) I/O. Also please don't argue semantics, it leads nowhere.

But that's not the main point. The main point is the Rust coreutils version of dd is slow. I highly doubt it's impossible to write an implementation in Rust that's as fast as the C one. But the Rust community needs to invest time and energy into finding why that's the case and fixing it. Until that happens the broader Linux community is right to push back on adopting it.