BSD subsystem for Linux.

Pretty much. Long predates WSL1, though, and facing many of the same difficulties that prompted the Windows team to just run Linux in a hypervisor (WSL2).

moonchild

> facing many of the same difficulties that prompted the Windows team to just run Linux in a hypervisor

How's that?

WSL had serious performance issues due to design differences between linux and NT. Linux and freebsd both being unices, there is no such impedance. Some features (like cgroups) remain unimplemented, true, but there haven't been any big difficulties afaik.

tony

Also interested in the response to the parent (loeg)

> facing many of the same difficulties that prompted the Windows team to just run Linux in a hypervisor

If by difficulties, you mean implementing system calls, this is being kept tabs on here: https://wiki.freebsd.org/Linuxulator

One that comes to mind is FreeBSD's kqueue, which opens a file descriptor for every file watched [1]

So inotify, inotify_add_watch, inotify_rm_watch isn't started. Lots of applications need watching of changes on directories. Even plain old FreeBSD gets messed since a large webpack project is going to chew up way too much.

If you're interested in this type of system call across operating systems check out https://github.com/emcrisostomo/fswatch

On WSL1/2:

Namely in WSL1, there were serious issues with package systems like npm, node_modules/ would have file descriptors get clogged, and it took a full system reboot to get WSL working again: https://github.com/microsoft/WSL/issues/1529. WSL2 Fixes it.

[1] https://emcrisostomo.github.io/fswatch/doc/1.8.0/fswatch.htm... See Freebsd -> kqueue -> Peculiarities