Overview
- Open-source developer Hailey published WSL9x on Codeberg under GPL-3, with source and build steps for running Linux alongside Windows 95, 98, or ME.
- The system combines a patched Linux 6.19 kernel, a Windows 9x VxD driver, and a tiny DOS client that opens a console window for Linux I/O.
- Linux syscalls are handled by the Windows 9x general protection fault handler, which detects the int 0x80 instruction and forwards it to the Linux kernel.
- Both kernels execute in ring 0, so a flaw or crash in one can bring down the other and the setup carries real security and stability risks.
- Because it avoids hardware virtualization, it can run on very old x86 hardware including 486-class PCs, though it is terminal-focused and requires a preinstalled Windows 9x disk image and specific cross-toolchains.