Windows Subsystem for Linux Announced at Build 2016

The Windows Subsystem for Linux was first revealed to the public via Windows 10 Insider Preview Build 14316, announced by Gabe Aul on April 6, 2016, around Microsoft’s Build developer conference that year. It went on to ship broadly with the Windows 10 Anniversary Update later that year.

What the original announcement actually offered

The initial WSL — what’s now referred to as WSL1 — worked by translating Linux syscalls into equivalent Windows NT kernel operations, without running an actual Linux kernel at all. This let a genuine Ubuntu userland run directly on Windows, sharing the filesystem with native Windows processes with near-native performance, but without full fidelity to real Linux kernel behavior for anything the translation layer didn’t implement.

Why this was a notable move for Microsoft

Shipping first-class Linux compatibility directly into Windows represented a significant shift for a company whose platform strategy had, for decades, been built around Windows as a closed, competing ecosystem. The move reflected a broader change in Microsoft’s developer-relations strategy during this period — embracing tools and platforms (Linux, open source more broadly) it had previously treated as competitors, in service of keeping developers working within the Windows ecosystem rather than dual-booting or virtualizing to get Linux tooling.

What came after

WSL1’s architecture was later superseded by WSL2, which runs an actual Linux kernel inside a lightweight virtual machine rather than translating syscalls — a considerably more compatible, if architecturally different, approach covered in more depth elsewhere on this blog. The Windows Subsystem for Linux project itself was made fully open source in 2025, continuing the same trajectory the original 2016 announcement started.

Sources: Windows Subsystem for Linux — Wikipedia, Fun with the Windows Subsystem for Linux — Windows Developer Blog