> I think it's possible to write a kernel with GC, and to still be judicious about memory usage with a GC language. ... but I will still afford that it is technically possible.

I need to split some hairs for a bit:

Do you mean what is colloquially referred to as "GC", as in the dotnet / Java / Javascript / golang "mark-and-sweep", fully-automatic style?

Or do you mean other automatic memory management systems, which some people technically define as GC, like automatic reference counting? (IE, they clean up memory immediately, and except for requiring some manual form of breaking cyclic loops, generally are fully automatic?)

Another part of it was, IIRC, that Longhorn was based off of the Windows XP core, i.e. the non-server stuff. While the Windows Server development continued apace, with lots of security and hardening to make for a reliable OS to build upon, the Windows Non-Server team continued with the existing mess of a codebase, not prioritizing security features or stability in favor of trying to manage feature creep. Longhorn was meant as a stopgap between XP and 'Blackcomb', but a lot of Blackcomb stuff started creeping backwards, bogging them down.

When security and reliability were suddenly key issues for Microsoft (to the extent that they ever were), it was obvious that what the Longhorn team had built was never going to meet that bar so they started over building off the Windows Server codebase instead.

Most of this story I remember from a video on YouTube of that old guy who worked at Microsoft since forever and left around the time of the Longhorn debacle, but a lot of it is corroborated in the Wikipedia article as well. https://en.wikipedia.org/wiki/Development_of_Windows_Vista

> trying to use .Net in the Windows kernel.

> Microsoft did that, it was called Longhorn

Do you have any reference for that? Or are you confusing Longhorn with Singularity (https://en.wikipedia.org/wiki/Singularity_(operating_system)) / Midori (https://en.wikipedia.org/wiki/Midori_(operating_system))?

I suspect you're referring to the shell/internals, though, not the kernel (https://longhorn.ms/the-reset/#:~:text=Why%20start%20over,re...)