We work very closely across the file system, kernel, and virtualization teams, so I don’t think we can blame Conway’s Law for WSL2. And actually our WSL1 fork performance wasn’t too bad IIRC—we have real fork at the Windows kernel level, it’s just not something that can realistically work with the Win32 programming model. I also think we will eventually resolve the file system performance issues.
No, the most important reason to choose a VM instead of a reimplementation of the Linux ABI is long tail compatibility. You can’t realistically replicate and then keep up with every corner of the Linux kernel’s interface. And so with WSL1, software will randomly not work, or it will randomly break after an apt upgrade, and users will get frustrated and switch to a VM anyway. Might as well get perfect compatibility and still have nice integration with Windows via the WSL2 approach.
No, the most important reason to choose a VM instead of a reimplementation of the Linux ABI is long tail compatibility. You can’t realistically replicate and then keep up with every corner of the Linux kernel’s interface. And so with WSL1, software will randomly not work, or it will randomly break after an apt upgrade, and users will get frustrated and switch to a VM anyway. Might as well get perfect compatibility and still have nice integration with Windows via the WSL2 approach.