[elihu]

> There's much more competition than there was when Linux was released and that competition is much more mature too.

I think it's the opposite. When Linux was released, basically every major tech company had their own variant of Unix. Now almost everyone has migrated to Linux or Windows.

Competing with modern Linux by creating a drop-in replacement for Linux would be a pretty difficult task given that people have been optimizing Linux for decades now, but on the other hand I think there are ways to improve dramatically on the traditional POSIX-style API that Linux mostly adheres to. For a random example, why can't a given process have more than one "current working directory" at a time? That seems like an arbitrary limitation imposed by an implementation detail in early Unix system, and it causes problems for modularity. There are many other little details like that. I think if Linux is replaced by something eventually, it'll most likely be because the new thing has a cleaner, more powerful, or more generally usable API.

(Kerla is apparently not trying to invent a new API; I'm just saying that's the direction I would recommend to anyone project with a goal of seriously competing with Linux.)

[elihu]

Follow up to add: another way to compete with Linux is on security. The Linux kernel generally has a pretty good security record I think, but there have been plenty of serious bugs over the years. How many exploitable array-out-of-bounds errors or use-after-free errors remain in the Linux kernel? No one knows. If you can rule those out by using a safer language, that might be compelling to a lot of users who care about security above other concerns.

Of course that's hard to pull off in practice. Linux might have classes of errors that wouldn't exist if it were written in Rust, but even if using Rust eliminates three fourths of the code defects, the end result could be less secure if Linux gets ten or a hundred times as much scrutiny from people actively looking through the code for bugs to fix.

[hnlmorg]

If OpenBSD has taught us anything, it's that when you need to start hardening at that level, C stops becoming weakest link and actually the design of the broader UNIX ABIs are the bigger problem. This is why things like selinux and cgroups exist in Linux -- POSIX ABIs are about as secure as Win32 APIs in Windows and thus you need to take additional steps to isolate your running processes if you really care about them behaving.

[hnlmorg]

> I think it's the opposite. When Linux was released, basically every major tech company had their own variant of Unix. Now almost everyone has migrated to Linux or Windows.

There wasn't many UNIXes that targeted x86 aside from 386BSD. And even those that were available were often expensive. Even Minix wasn't free at that time. Which is exactly the reason Linus created his hobby OS.

Now we have a dozen different flavours of BSD, countless Linux distributions and several OpenSolaris spin offs too. Plus many other underdogs used in speciality domains. And that's before even looking at the commercial offerings like QNX, Solaris and macOS.

Just because there are a couple of industry heavyweights that take up the majority of common use cases, don't be fooled into thinking there is a lack of choice nor even that the industry is scared to use anything outside of Linux and Windows.

> Competing with modern Linux by creating a drop-in replacement for Linux would be a pretty difficult task given that people have been optimizing Linux for decades now, but on the other hand I think there are ways to improve dramatically on the traditional POSIX-style API that Linux mostly adheres to. For a random example, why can't a given process have more than one "current working directory" at a time? That seems like an arbitrary limitation imposed by an implementation detail in early Unix system, and it causes problems for modularity. There are many other little details like that. I think if Linux is replaced by something eventually, it'll most likely be because the new thing has a cleaner, more powerful, or more generally usable API.

That's not the goal of this nor any other project that aims for ABI compatibility with Linux and there are plenty of research kernels out there if that's your thing.

> (Kerla is apparently not trying to invent a new API; I'm just saying that's the direction I would recommend to anyone project with a goal of seriously competing with Linux.)

The only way to seriously compete with Linux would be to get large commercial backing. And even then, good luck. Linux won not because it is the best but instead because it's "good enough". Same is true with Windows. Any engineer with aspirations of creating a "better kernel" or "better OS" needs to remember that.