Microsoft invited free software legend Richard Stallman to speak at its Microsoft Research headquarters this week. Stallman, known for launching the Free Software Movement to develop the GNU operating system, was and still is a staunch Microsoft critic. Microsoft’s ongoing embrace of open source has resulted in some fairly surprising moves for the company. A Microsoft-built Linux kernel in Windows 10? Check. Bringing SQL Server to Linux? Done. Open-sourcing big chunks of .NET? It happened.