very good

What about it makes it the wrong tool for the job?

This should be http://ericsink.com/entries/rust1.html

Why can't one use Cargo for bare-metal applications?

See all the extra work that had to be done here: https://github.com/Ogeon/rust-on-raspberry-pi

In some cases, especially new projects (like a new OS), I think the pain of using an immature-and-powerful language is less than using a mature-and-weak one.

No one knows, and I don't think there's been (a public) discussion about it by projects leads. The only guarantee is that 1.x will not break anything (according to some definition of "break").

There needs to be more experience with widespread use and multiple releases, to see how far that backcompat can be held. Perhaps after 10 releases, it should be a lot more clear whether or not a Rust 2.0 will be needed.

Thanks; I'm not sure in that case saying 1.x is guaranteed to not break things is very useful at all. Systemd (as far as I know) follows semantic versioning, but their version number is up in the hundreds. Without some sort of guess at how long a release might last, 2.0 might as well ship the minute after 1.0 ships. (Okay, probably not...)

The core team has reserved the right to break backcompat without changing the major version if they find a serious problem in 1.x series. So I expect that it will be a while (at least a few years) before 2.0 is created.

I don't think systemd does follow any semantic versioning: each of the feature releases change the major version.

nice catch :)

Would also be nice if the cp replacement (optionally) checks for available storage space before copying files.

I think you should replace 'time' with 'a lot of time'. I've seen several commits that optimize things.

most of the stuff; there are some notes when stuff is outdated