In the over 50 years since its introduction, the fork system call has evolved from a simple system call into a slow, complex behemoth that pervades many operating system (OS) primitives and hinders the implementation of superior OS concepts. There exists a multitude of issues with the fork system call, and programmers are encouraged to use alternatives such as posix_spawn. However, migration to new APIs is not happening, as shown by the analysis in this paper. To pave the way for new OS concepts, we propose Spork, a flexible emulation layer that eliminates fork. Spork enables fork-free operating systems while maintaining backward compatibility with legacy software that uses the fork system call. Without the need for kernel-level fork functionality, Spork also solves many of the issues caused by fork for 84 % of existing legacy software in modern Linux distributions.

This is a follow-up to last year's talk about the issues which the fork system call presents to both applications and operating systems. This year's talk will focus on our work we have done since then, which was published at HotOS'25: https://doi.org/10.1145/3713082.3730396