Microsoft today ad The Windows subsystem for Linux version 2, which is WSL 2. It will offer "dramatic improvements in file system performance" and support for Docker. To make all this possible, Windows 10 will have a Linux kernel.
No, Microsoft does not make Windows 10 a Linux distribution. It will still be based on the Windows kernel. But Microsoft "will provide a real Linux kernel with Windows that will make total system call compatibility." The kernel will be compiled by Microsoft on the basis of the last stable branch of the kernel.org source code. It will initially be based on version 4.19 of the Linux kernel.
The Linux kernel of Microsoft will be optimized for WSL 2 and "optimized in terms of size and performance to deliver an amazing Linux experience on Windows". The Linux kernel will be updated via Windows Update. Yes, you will get Linux kernel security updates through Windows Update. The full kernel source code will be available online on Github.
This Linux kernel is optimized for small size, improved boot times, and reduced memory usage. It will replace "the emulation architecture described in the design of WSL1".
This drastic change means that WSL now offers better file system performance. It offers full compatibility with system calls. This means that you can run Docker and other Linux applications on Windows using WSL 2. However, this is not as slow as a virtual machine. It's as fast as WSL 1, or faster. Here is what Microsoft says about it:
File-intensive operations such as git clone, install npm, apt update, apt upgrade, etc. will be significantly faster. The actual increase in speed depends on the application you are using and the way it interacts with the file system. The initial tests we performed have WSL 2 up to 20x faster compared to WSL 1 when uncompressing a compressed archive, and about 2 to 5 times faster when using git clone, npm install and cmake on various projects. We look forward to seeing community speed comparisons when we publish!
The initial release of WSL 2 will arrive by the end of June 2019 in the Windows 10 initiated versions. Read Microsoft Blog for more details on his Linux kernel projects.
Microsoft launches a new Windows Terminal application this will also improve the operation of the next version of WSL.