The current Windows Subsystem for Linux uses a component of kernel created by Microsoft that provides the same kernel API as the Linux kernel, but it was written from scratch by Microsoft.
Essentially, he translated from Linux APIs to Windows NT kernel APIs. This worked very well, but the current subsystem had some shortcomings: there was no capacity, for example, to use Linux drivers, in particular file system drivers.
The performance of the file system, layered on top of the Windows' own NTFS, used to be 20 times slower than a real Linux kernel.
It was also a relatively old version of the kernel; It offered roughly the set of APIs that Linux 4.4 did and which was released in 2016. Some APIs are not implemented, and others are only partially implemented to meet the needs of specific applications.
New Windows 10 Update
Everything is changing with the Windows Subsystem for Linux 2. Instead of emulating the Linux kernel APIs in the NT kernel, the WSL 2 will run a full Linux kernel in a lightweight virtual machine.
East kernel will be shortened and adapted for this specific use case, with reduced hardware support (since it will be deferred to the host Windows OS for that) and faster boot.
The Linux kernel is open source GPL; the GPL license requires that any modifications made to the code be published and made available under the GPL license.
Microsoft will comply with this by publishing the patches and modifications it makes to the kernel. WSL 2 will also use a similar split as the current WSL does: the kernel component will ship with Windows, while the various Linux distributions will be able to be installed from the Microsoft Store.
Using the Linux kernel itself, Microsoft gets all Linux features for free.
That's why the WSL 2 will support Docker containers: All underlying infrastructure such as cgroups is already in the Linux kernel, and Microsoft will not need to implement the features themselves. Embedded kernel will be serviced and updated by Windows Update.
- Microsoft prepares new Windows 10 interface with rounded corners
- PC with USB storage or SD card will not update to Windows 1903 version 10
See the image above for a quick demo of WSL 2 in action. When we start our tests, we have access to a working shell in less than two seconds, and we can run services and applications like docker right away.
This also provides a huge performance boost. Heavy filesystem operations, such as extracting a tarball, can be up to 20 times faster; other activities (such as cloning source code repositories in Git) will be maybe five times faster.
A WSL has already been very well received by the developers, as it provides an environment of solid Linux-like development. The WSL 2 will take this to a new level and eliminate all the compatibility issues that WSL 1 It has.
The first preview of WSL 2 is expected to be released in June.
