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by kragen 746 days ago
apple started with mach, which was a microkernel, and linked basically all of the freebsd kernel into it, morphing it from a microkernel operating system into a monolithic operating system

i agree that monolithic kernels are unpleasant and brittle, but unfortunately they don't actually seem to be obsolete
3 comments
pjmlp 746 days ago
NeXT you mean.

Additionally, Apple has a long term roadmap to fix that design decision, hence why they are killing one kernel subsystem at a time, moving them into userspace, with one year given for the developers to adopt each of them, after being made available as the new way.

Finally, it is kind of ironic that systems that have doubled down on monolithic kernels, are now used to run an endless pile of containers and Kubernetes clusters.

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darby_nine 745 days ago
> hence why they are killing one kernel subsystem at a time, moving them into userspace, with one year given for the developers to adopt each of them, after being made available as the new way.

Notably they aren't exposing most of the functionality, it wouldn't be possible to e.g. implement NFS or 9p with the userspace filesystem thing they've been pushing. They're basically just shutting users out from their own computer....

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kragen 746 days ago
well said
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darby_nine 746 days ago
> apple started with mach, which was a microkernel, and linked basically all of the freebsd kernel into it, morphing it from a microkernel operating system into a monolithic operating system

The microkernel aspect of it had completely vanished by the time they hit the general public.

> i agree that monolithic kernels are unpleasant and brittle, but unfortunately they don't actually seem to be obsolete

Of course they aren't obsolete! The security in your phone depends directly on sel4, at least if you use an apple device. They just aren't relevant to most of the compute and most of the software you interact with today or in all of history.

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kragen 746 days ago
you seem to have thought i said 'unfortunately microkernels aren't obsolete', but that is the opposite of what i said
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eschaton 745 days ago
Mach as deployed at NeXT was also never a microkernel, and combined the BSD 4.2 kernel. I believe this is also effectively what OSF/1 did with the OSF variant of Mach.

Mach has basically always supported that kind of use, even back to early CMU research versions.

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