ReactOS Merges Asynchronous TCP Support After Decade-Long Effort

The ReactOS project, an open-source implementation of a Windows-compatible operating system, has merged a critical networking enhancement after ten years of development. This week, developers successfully integrated asynchronous TCP support into the main codebase, addressing a fundamental limitation that has constrained networking performance since 2016.

This breakthrough resolves Jira ticket ROS-20160718-01 originally filed when developers discovered ReactOS's TCP stack couldn't properly handle non-blocking socket connections. The deficiency forced networking applications to operate in synchronous mode, creating significant performance bottlenecks. As lead developer Victor Perevertkin noted in the merge announcement: "After 10 years, asynchronous TCP support patch is now merged into #ReactOS. You can expect substantial performance improvements in networking apps."

The technical implementation allows ReactOS to manage multiple concurrent network operations without blocking execution threads. Where previously a browser might freeze while waiting for server responses, the OS can now process incoming data while continuing other operations. This architectural shift particularly benefits:

• Web browsers (page loading efficiency)
• FTP clients (parallel file transfers)
• Download managers (concurrent connections)
• Real-time applications (reduced latency)

Engineers achieved this through multiple iterative pull requests refining the Winsock API implementation. The final solution involved restructuring how the kernel handles I/O completion ports and socket state management while maintaining binary compatibility with Windows network drivers.

Initial benchmarks conducted by Phoronix show 3-5x throughput improvements in synthetic network tests, with real-world browser loading times cut by approximately 40%. These gains position ReactOS closer to its goal of becoming a viable Windows alternative for legacy application support.

The code is available in nightly builds immediately, with stable release inclusion expected in the upcoming 0.4.15 version. Developers recommend testing network-intensive applications and reporting compatibility results via the project's GitHub repository.