Microsoft's WSL 2 launches the year of Linux on the desktop

Microsoft has announced its intention to make 2019 the year of Linux on the desktop, through the Windows Subsystem for Linux 2 - its first version to include an in-house Linux kernel, which will ship as standard with Windows 10.

First made publicly available back in March 2016 ahead of its general release in the Windows 10 Fall 2017 Creators Update, the Windows Subsystem for Linux does exactly what its name implies: Packing a Linux kernel, traditionally provided by third-party partners like Canonical, it allows Linux software to run sort-of-directly on Windows using a variant of a virtual machine environment.

Now, the company has announced the upgraded Windows Subsystem for Linux 2 which will for the first time include a Microsoft-built Linux kernel shipped directly inside Windows 10, effectively bringing about the much-vaunted and always just-around-the-corner year of Linux on the desktop - albeit not quite in the way anyone expected.

'We will be shipping a real Linux kernel with Windows that will make full system call compatibility possible,' Microsoft's Craig Loewen, programme manager for the Windows Developer Platform, writes in a blog post. 'This isn’t the first time Microsoft has shipped a Linux kernel, as we have already shipped one in 2018 when we announced Azure Sphere. However, this will be the first time a Linux kernel is shipped with Windows, which is a true testament to how much Microsoft loves Linux! We’ll be building the kernel in house from the latest stable branch, based on the source available at kernel.org. In initial builds we will ship version 4.19 of the kernel.

'This kernel has been specially tuned for WSL 2. It has been optimised for size and performance to give an amazing Linux experience on Windows. We will service this Linux kernel through Windows updates, which means you will get the latest security fixes and kernel improvements without needing to manage it yourself.Lastly, of course this Linux kernel will be fully open source! When we release WSL 2 we will have the full configuration available online on GitHub, so you can see how it works and build it yourself.'

Loewen claims that changes under the hood in WSL 2 improve its performance - particularly for file-system-heavy tasks, which Microsoft has measured at up to 20 times faster than WSL 1 - while adding complete compatibility for all Linux system calls to further improve compatibility with Linux software.

The first WSL 2 public builds will be made available to beta testers registered in the Windows Insider programme late June, Loewen has confirmed, with no confirmation yet when it will be made more generally available.