[ablob]

C# has had the reputation of not being viable for Linux for a long time. Therefore, the people already on Linux didn't have a reason to use it or even try it. If you're already doing stuff in other languages it's hardly worth it to switch to C#.

I personally use it quite a lot - but I came as a windows user writing all my utilities in C#. Also, afaik C# is mostly used in corporate environments that don't open-source their projects. You're unlikely to hear from it unless you're working on it for this very reason.

[drzaiusx11]

Mono was in a usable state on Linux for literal decades before becoming official and integrated into what is core today, that is unless you needed windows forms, which much like MSFT UI frameworks today had multiple failed attempts spanning those same decades...

[seabrookmx]

Only if you didn't care about performance.

We attempted a move to mono for backend web services maybe 3 years before .NET Core released, and it was a complete no-go. 10x reduction in performance on the same hardware.

This wasn't specific to our workload either. I was big into the game Terraria at the time, and I saw similarly poor performance when running it's game server under mono vs .NET 4.x

While some of the mono toolchain was integrated into .NET Core, CoreCLR was a rewrite and immediately solved this problem.

[drzaiusx11]

Great context, thanks! I knew it worked (I closely followed mono development at the time) but I didn't have a windows license/windows machines at the time it was ongoing to compare it to. 4x is pretty bad, any ideas what went wrong? Lack of jit maybe? I forget the exact architecture of mono at that time, being like 20 years ago...

[seabrookmx]

It did have a JIT, it just wasn't a very performant one. I recall the GC implementation also being quite slow. GC is an area where .NET is still making strides.. we got a new collector in .NET 10.

[WorldMaker]

A lot of C#'s reputation for not being viable for Linux came from the other direction and a lot of FUD against Mono. There were a lot of great Linux apps that were Linux first and/or Linux only (often using Gtk# as UI framework of choice) like Banshee and Tomboy that also had brief bundling as out-of-the-box Gnome apps in a couple of Linux distros before anti-Mono backlash got them removed.

Also, yeah today Linux support is officially maintained in modern .NET and many corporate environments are quietly using Linux servers and Linux docker containers every day to run their (closed source) projects. Linux support is one of the things that has saved companies money in running .NET, so there's a lot of weird quiet loyalty to it just from a cost cutting standpoint. But you don't hear a lot about that given the closed-source/proprietary nature of those projects. That's why it is sometimes referred to as "dark matter development" from "dark matter developers", a lot of it is out there, a lot of it doesn't get noticed in HN comments and places like that, it's all just quietly chugging along and doesn't seem to impact the overall reputation of the platform.

[pjmlp]

Yes, however as acknowledged by the .NET team themselves, in several podcast interviews, this is mostly Microsoft shops adopting Linux and saving Windows licenses.

They still have a big problem gaining .NET adoption among those that were educated in UNIX/Linux/macOS first.

Mandy Mantiquila and David Fowler have had such remarks, I can provide the sources if you feel so inclined.