Windows Subsystem for Linux Announced at Build 2016
First revealed via Windows 10 Insider Preview Build 14316 on April 6, 2016, WSL let Windows run real Linux binaries for the first time.
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WSL1’s architecture was later superseded by WSL2, which runs an actual Linux kernel inside a lightweight virtual machine rather than translating syscalls — a considerably more compatible, if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.
The Canonical partnership behind the specific choice of Ubuntu
WSL’s original announcement wasn’t purely a Microsoft engineering effort — it was the product of an explicit partnership with Canonical, Ubuntu’s parent company, publicly detailed by Canonical’s Dustin Kirkland around the same March 2016 timeframe as the broader announcement. Kirkland described the collaboration specifically as bringing the genuine “Ubuntu userspace” — real, unmodified Ubuntu binaries — to run directly on Windows, rather than Microsoft building its own independent Linux-compatible environment from scratch and merely branding it with Ubuntu’s name. That distinction mattered concretely: applications and tools already compiled for Ubuntu could run under WSL without needing a Windows-specific rebuild, since the actual userspace binaries were the same ones a genuine Ubuntu installation would run, with WSL1’s kernel-syscall-translation layer doing the work of making Windows NT understand what those binaries expected from a Linux kernel underneath them.
From Insider Preview to general availability
The April 2016 reveal via Insider Preview Build 14316 was explicitly a preview for Windows Insiders — testers running early, pre-release Windows builds — rather than a feature immediately available to the general Windows 10 population. WSL1 subsequently shipped broadly to all Windows 10 users with the Anniversary Update (version 1607) in August 2016, still labeled as a beta feature at that point and requiring Developer Mode to be manually enabled before it could even be installed — a deliberately cautious rollout for a capability this architecturally significant, giving Microsoft real-world usage data from the more technically engaged Insider and developer population before exposing the feature more broadly to Windows’ full mainstream installed base.
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