WSL9x runs a modern Linux kernel (6.19) cooperatively inside the Windows 9x kernel using a VxD driver, enabling concurrent use of both OSes without rebooting.
Key Takeaways
Three components: a patched Linux kernel (win9x-um-6.19 branch), a VxD driver written in ASM/C, and a 16-bit DOS wsl.com client program.
The Linux kernel is based on user-mode Linux but calls Win9x kernel APIs instead of POSIX, running in ring 0 rather than ring 3.
Syscalls via int 0x80 are intercepted through the GPF handler since Win9x lacks a long enough IDT for a proper int 0x80 handler.
The wsl.com client uses MS-DOS prompt windows as TTYs; ANSI color support requires loading a driver like nnansi.com separately.
Build requires i386-linux-musl cross toolchain, Open Watcom v2, a pre-installed Windows 9x hard drive image, and a manual kernel build step.
Hacker News Comment Review
No substantive HN discussion yet; the thread was flagged by one commenter for duplicate submissions, with another noting all submitters were different and that HN should handle deduplication automatically.
