News: 0177644497

  ARM Give a man a fire and he's warm for a day, but set fire to him and he's warm for the rest of his life (Terry Pratchett, Jingo)

Microsoft Open Sources Windows Subsystem for Linux (thenewstack.io)

(Monday May 19, 2025 @05:30PM (msmash) from the moving-forward dept.)


Windows Subsystem for Linux (WSL) is [1]now open source , Microsoft said Monday. The tool, which allows developers to run Linux distributions directly in Windows, is available for download, modification, and contribution. "We want Windows to be a great dev box," said Pavan Davuluri, corporate VP at Microsoft. "Having great WSL performance and capabilities" allows developers "to live in the Windows-native experience and take advantage of all they need in Linux."

First [2]launched in 2016 with an emulated Linux kernel, WSL switched to [3]using the actual Linux kernel in 2019 with WSL 2, improving compatibility. The system has since gained support for GPUs, graphical applications, and systemd. Microsoft significantly refactored core Windows components to make WSL a standalone system before open sourcing it.



[1] https://thenewstack.io/the-windows-subsystem-for-linux-is-now-open-source/

[2] https://linux.slashdot.org/story/16/04/06/208234/new-windows-10-preview-for-pcs-with-bash-cross-device-cortana-released

[3] https://linux.slashdot.org/story/19/06/13/1442201/windows-10s-linux-kernel-is-now-available



Linux is already a great Dev environment (Score:4, Interesting)

by Virtucon ( 127420 )

As MSFT clings to keeping you on the mothership, we are over here developing real apps on Linux and not worrying about Windows.

Re: (Score:3)

by skullandbones99 ( 3478115 )

In the enterprise environment, Microsoft's core applications of Outlook, Teams and Office365 are available as cross-platform web based or PWA applications. I use Ubuntu 22.04 with a KDE Plasma desktop at work and I can access all the MS applications that I need to use on Linux. The days of the Microsoft lockin have dissolved away.

I don't have a MS Windows system for me to run WSL2 but I don't think that I am missing out. ;-)

Re: (Score:2)

by fluffernutter ( 1411889 )

You access a web version of that MS application, not the actual MS application. Web versions aren't as integrated with the desktop.

Re: (Score:3)

by blackomegax ( 807080 )

It can read and write files locally. PWA may be a web wrapper, but it's as near native as i care to get with MS. I can't tell the difference between PWA on linux and o365 native on windows 99.999999999% of the time.

They did WSL totally backward. (Score:5, Insightful)

by Anonymous Coward

Was a mistake to make Windows the host and Linux the guest.

Gives you all the stability and security Windows is infamous for, with all the ease of use that Linux is infamous for.

Would have been far better to make Linux the host OS, and Windows the guest UI to replace Gnome.

Re: (Score:2)

by IWantMoreSpamPlease ( 571972 )

Wish I had mod points, this needs more visibility.

Re: They did WSL totally backward. (Score:2)

by simlox ( 6576120 )

It it made for all those Windoze only places where they of course need Linux. A lot of IT departments will not allow anything but Windows on the laptop/desktop for "security" (read: it is the only OS where they can keep control over the user). WSL makes it possible to deny Linux installs but still install it in a MS sanctioned way (therefore safe).

Re: (Score:2)

by rtkluttz ( 244325 )

I think the same thing. Running linux in windows is like setting up a hospital operating room in the middle of a landfill.

Two questions after reading the article: (Score:2)

by Koen Lefever ( 2543028 )

Where is the repository?

Under which license did MS release WSL?

Re:Two questions after reading the article: (Score:4, Informative)

by Anonymous Coward

[1]The direct blog post from Microsoft is more descriptive. [windows.com] It looks like it's MIT licensed, according to the [2]GitHub repository. [github.com]

[1] https://blogs.windows.com/windowsdeveloper/2025/05/19/the-windows-subsystem-for-linux-is-now-open-source/

[2] https://github.com/microsoft/WSL

Does it matter? (Score:1)

by RazorSharp ( 1418697 )

It is not like they open sourced Windows. They open sourced a small appendage of a proprietary system as an attempt to lure users into the proprietary system. Their code is useless without a Windows license.

Re:Does it matter? (Score:5, Funny)

by OrangAsm ( 678078 )

Damn, I was hoping to run in under Wine on Linux.

Re: (Score:2)

by eneville ( 745111 )

My initial thoughts were along these lines, you may jest, but developers working on modern things have mostly moved on from Windows, so it would make more sense for MSFT to focus on WINE compatibility.

Azure brings in the big money, so focusing on Windows is a lost venture now (Windows 10 was meant to be the last).

Re: (Score:2)

by wierd_w ( 1375923 )

It COULD (in theory, at least) get directly cabbaged up by something like ReactOS though.

MIT allows re-licensing under new terms (GPL Primacy), IIRC.

Whether or not ReactOS is .... Mature enough.... (giggle)... to accept the newly opened code as a viable POSIX subsystem provider is another matter entirely, however.

Still, Gift horses and mouths, and all that.

Re: Does it matter? (Score:1)

by drinkypoo ( 153816 )

"Their code is useless without a Windows license."

Probably, but as they have used a permissive license, if there are parts in there that are good for other purposes they will be usable.

lol troll (Score:2)

by drinkypoo ( 153816 )

I am still rent-free in this clown's head all day every day.

Re: (Score:2)

by unrtst ( 777550 )

Trolling yourself and lamenting the lack of an edit button, I presume :-)

Virtual Machine (Score:3)

by akw0088 ( 7073305 )

I thought WSL was a virtual machine after the update that improved performance over their API hook kernel? So essentially Virtual box, but tied to windows and powershell

Cygwin (Score:3)

by Errol backfiring ( 1280012 )

It is just a Virtual Machine. If you want a real subsystem for Linux under Windows, you still have to install Cygwin.

Re: (Score:3)

by jonwil ( 467024 )

It is a VM but it has a lot of special bits that allow much better integration with Windows than running a standard Linux distro in a standard VM would give you (and its these that are being made open source)

Shouldn't it be called (Score:3)

by Valgrus Thunderaxe ( 8769977 )

Linux subsystem for Windows?

Re: (Score:3)

by transwarp ( 900569 )

It's a Windows Subsystem that provides Linux, in addition to the Windows Subsystem that provides Win32, and the old Windows Subsystem that provided Unix, and the Windows Subsystem that provided OS/2.

If NT had ended up with as many supported APIs as VMS had, we'd probably find the term mundane.

Re: (Score:2)

by Bert64 ( 520050 )

WSLv1 was.

WSLv2 is just a vm running in hyper-v with some paravirt hooks to allow better integration with the host, similar to what vmware or parallels has had for years.

Re: (Score:2)

by ClickOnThis ( 137803 )

> Linux subsystem for Windows?

You misspelled "wine".

Re: (Score:2)

by allo ( 1728082 )

That's the company that puts its 32-bit libraries in a folder called WOW64 while the 64-bit libraries are in the system32 folder.

For those who have to use Windows WSL is great (Score:2)

by linuxguy ( 98493 )

Some of us have to use Windows for one reason or another at least part time. WSL is totally awesome for those times! I am glad it exists. And now it is getting an opensource license makes it even better.

Re: (Score:2)

by fluffernutter ( 1411889 )

I have been working for a long time and there was only around 5 years in my entire career that the workstation was linux. The rest of the time it was windows.

Have they open sourced WSL 1? (Score:2)

by butlerm ( 3112 )

Personally, I am more interested in WSL 1 than WSL 2, and would like to find out if they have open sourced the former. Either way, congratulations to Microsoft for sharing this with the world, as they did with .NET Core and a couple other things I can recall previously.

Thanks... however (Score:2)

by 93 Escort Wagon ( 326346 )

For me, at least, it'd be more useful for Microsoft to open-source (or at least make it "free as in beer") Windows - that way I could live the Linux-native (or Mac-native) experience and "take advantage of all I need in Windows" (which is not all that often).

Regardless - kudos to Microsoft for this move.

Fearing Recall, with Dual-Booting, WSL a Concern (Score:2)

by BrendaEM ( 871664 )

As a long-time Window, Linux, and Mac user, and with the implementation of Windows Recall spyware, I am concerned that even a Linux drive connected to a machine that also runs Windows that data may be searched and gathered from it. I am trying to work out a system that when I need to use the Windows software I own, that only the data it needs to see--is the only data it sees. Perhaps Windows Subsystem for Linux will add to that threat.

California's District Attorney should investigate Microsoft's Recall sp

Is Microsoft's Binary the Same as Built Ones? (Score:2)

by BrendaEM ( 871664 )

Even though the source is out there--does it build the same?

Link? (Score:2)

by allo ( 1728082 )

It seems that neither Slashdot nor the original article link a repo? What is an article about an open source project without a link to the source?

A Question nobody ever asked. (Score:2)

by polyp2000 ( 444682 )

Why is it called "Windows Subsystem for Linux" and not "Linux Subsystem for Windows" ?

Are there those in the land of the brave
Who can tell me how I should behave
When I am disgraced
Because I erased
A file I intended to save?