1. Bash on Ubuntu on Windows
Taiwan Evolutionary Intelligence Laboratory
Lin, Yuen-Jen

2. Outline
Background
Architecture
Technical details
Demo

3. Background Threatened in developer market by Linux and Mac OS X
Cooperate with Canonical
From project Astoria (abandoned), which originated to run Android apps on Windows 10

4. Background
Bash on Ubuntu on Windows: Service that users can use Linux on Windows
Windows Subsystem for Linux (WSL): the function build in Windows that Bash on Ubuntu on Windows relies on.

5. Architecture

6. Architecture
User mode session manager
Pico sessions
Pico drivers

7. Architecture Linux Application Windows Application Pico Driver
NT kernel

8. Technical details
Pico process
Pico Drivers
File systems

9. Pico process Decouple OS dependencies from the underlying host OS
Run in the “library OS”
Separate the host OS from trying to manage the user- mode address space inside it.
When Windows kernel detect system calls from a pico process, it passes to pico provider to handle.

10. Pico Process

11. Pico drivers Difference between Linux and Windows: System calls,
Application Binary Interface (ABI)
What Pico drivers have to do:
Transfer Linux system calls to Windows system calls
Pass the parameters using the registers defined by the Linux ABI

12. Pico drivers

13. File Systems Linux uses the Virtual File System (VFS)
VolFs: the file system designed to emulate VFS in WSL.
DrvFs: designed to facilitate interoperability with Windows. Windows drives, such as C: and D:, are mounted under /mnt.

14. File Systems

15. Demo

16. Demo

17. Demo

18. Demo

19. Demo

20. Demo

21. What is different from containers
Translation between different syscall systems
Different level of separation

22. Conclusion New way for using Linux on Windows machine
Looks powerful but limits exist

23. Reference WSL blog, https://blogs.msdn.microsoft.com/wsl/
Image source:
WSL blog
applications/w/wiki/6950.lxc-containers-in-ubuntu- server lts