macOS 10.15 Catalina: What's new at the KERNEL level?

[applCore]

What has everyone seen at the kernel level that's new?

Apple has forgotten for a long time (according to various Apple "core OS" engineer buddies) that the kernel and core OS innovations are important. We're at a point now where Linux (kernel) has surpassed Apple in this area (as of about 10 years now) and it's caused a lot of us a huge number of problems for a long time now. Apple's got to be brought to realize that we, as users, know what they're doing - the iDevices may make money, but WE use the computers to help them make the money! They've gotta focus on performance and stability at the very core kernel level vs throwing more and more speed at - and they need to still allow us to have flexibility to muck around in and with the kernel and kexts if we want to.

I'm hoping all of us can share observations and discoveries from the lower levels of the operating system here.

 

[newadventure]

At the WHAT level?

 

[applCore]

At the WHAT level?

XNU. And a very basic comparison of Linux vs XNU.

 

[Speedstar]

PCIe-pass through VX-T is interesting ... in darvin....

 

[webg3]

What I can say, I have noticed since Mac OS X Lion 10.7: the kernel has been a large accumulation of "new" features, and has become bloated. As much as with an SSD and more and more cores in the processors, this is not perceptible, there is a big problem here.

 

[Ritsuka]

How can you say it's bloated? It's very hard to compare a kernel to another, it requires a lot of specific knowledge that almost no one has.

XNU is open source, so one can learn about it and compare it to linux, but I think no one on this forum can do it.

 

[toru173]

I was able to get macOS (or rather, XNU) down to the kernel, the dynamic linker, a few libraries and a shell. Couldn't even shut down gracefully - it had to crash instead. A pre-compiled kernel cache (or prelinkedkernel) is only 20-25mb, and the whole install was approximately 75mb. Not what I'd consider bloated!

If there is interest I can do a quick howto, but I don't think it would help us learn more about the kernel than static analysis of the source.

 

[webg3]

How can you say it's bloated? It's very hard to compare a kernel to another, it requires a lot of specific knowledge that almost no one has.

XNU is open source, so one can learn about it and compare it to linux, but I think no one on this forum can do it.

I meant the system itself, not just the kernel.

 

[AnonMac50]

I was able to get macOS (or rather, XNU) down to the kernel, the dynamic linker, a few libraries and a shell. Couldn't even shut down gracefully - it had to crash instead. A pre-compiled kernel cache (or prelinkedkernel) is only 20-25mb, and the whole install was approximately 75mb. Not what I'd consider bloated!

If there is interest I can do a quick howto, but I don't think it would help us learn more about the kernel than static analysis of the source.

Actually that would be interesting.

 

[applCore]

@Ritsuka, there are some of us who can do this - but time to do it is another thing.

@toru173 we do need an actual forum or platform (maybe Discourse?) to have these kinds of discussions at a low level. As Apple forges ahead in focusing on user level features (that translate to the zombie masses oooo's and ahhhhh's), especially things that are beneficial for the iOS side of devices, it is becoming increasingly evident that we must have a platform for folks who want to dig about and understand things better to collaborate.

For example, I've had a devil of a time with the last two OS releases with some very difficult hangs and speed quirks. Apple is 9 times out of 10 either crickets or push the issue off onto someone else. No one talks about how to isolate system calls or analyze samples for apps and so forth. Further, there are some tutorials on kernel debugging - but where can you go to talk to people about really groking kernel debugging facilities?

And what about Darling? That's an amazing opportunity, especially for those of us who don't want to give up 32-bit... OR those of us who would rather use Linux (kernel) instead of XNU...

 

[baddj]

@applCore at this url from a WWDC2019 video https://developer.apple.com/videos/play/wwdc2019/103/

at 0:40:15 they talk about some kernel stuff there.

 

[Jyby]

Science Rules!

 

[applCore]

Ugh, this seems very disturbing and very possible that Mojave may be the last sane macOS release while Catalina is fringe unusable with missing 32-bit. Thanks for these tidbits guys. Much more of a reason to get behind Darling.

For many of us the reason for using macOS is the Unix-base flexibility. If they make don't allow people freedom to operate at the lowest levels of the operating system (which it sounds like they're trying to frame this in a positive light while still exerting more control over the kernel level stuff), then macOS is going to die fast and hard for more advanced users.