> Ah, yes. Drew DeVault. The expert in ... developing 30M LOC OS kernels with billions of dollars on R&D investment in a few years with a small team in an experimental language. "Just make Linux 2", it's so simple, why didn't we think of this?!

This is an unusual take considering Drew DeVault actually does have experience developing new kernels [1] in experimental languages [2].

Drew's own post [3] (which the linked article references) doesn't downplay the effort involved in developing a kernel. But you're definitely overplaying it. 30M SLOC in the Linux kernel is largely stuff like device drivers, autogenerated headers, etc. While the Linux kernel has a substantial featureset, those features comprise a fraction of that LOC count.

Meanwhile, what Drew's suggesting is a kernel that aims for ABI compatibility. That's significantly less work than a full drop-in replacement, since it doesn't imply every feature is supported.

Not to mention, some effort could probably be put into developing mechanisms to assist in porting Linux device drivers and features over to such a replacement kernel using a C interface boundary that lets them run the original unsafe code as a stopgap.

[1] https://sr.ht/~sircmpwn/helios/

[2] https://harelang.org

[3] https://drewdevault.com/2024/08/30/2024-08-30-Rust-in-Linux-...