It used to be, Tahoe is generations away from NeXTSTEP.

NeXTSTEP drivers were written in Objective-C, originally OS X used C++ subset based on COM (IO Kit), now moved into userspace and called Driver Kit, in homage to the NeXTSTEP DriverKit name.

NeXTSTEP was focused on OpenGL and Renderman, OS X used OpenGL, macOS is now using Metal.

NeXTSTEP drivers were on kernel space, now everything is moving into userspace.

NeXTSTEP used Display Postscript, OS X moved into PDF subset, nowadays that is only part of the rendering stack.

NeXTSTEP had a X Windows Server as well, on macOS that is now gone.

macOS Finder is nothing like the NeXTSTEP file application.

NeXTSTEP supported a concept similar to OLE, it is nowhere to be seen on macOS.

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jdboyd 2 days ago | parent | next [-]

Is macOS in any recognizable way still a micro-kernal operating system or did that get removed as well?

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pjmlp 2 days ago | parent [-]

OS X was never a proper micro-kernel, rather an hybrid one like Windows NT, using still a micro-kernel like approach but with subsystems on the same process space.

https://fahrplan.events.ccc.de/congress/2007/Fahrplan/attach...

https://www.amazon.de/-/en/Mac-OS-Internals-Approach-paperba...

If anything it is going more into that direction, after Apple announced removing all kernel extensions, and having userspace counterparts to them.

https://developer.apple.com/documentation/SystemExtensions

https://developer.apple.com/documentation/systemextensions/i...

Usually it takes one OS version between introducing new userspace APIs, and removing the old way on the following version.

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wpm 2 days ago | parent [-]

Apple removed third-party kernel extensions (and even so only removed the ability to install them without going into recovery and changing a scary box). There are still lots of .kext files in the /System folder for hardware drivers.

	▲	pjmlp 2 days ago \| parent [-]
		Yes, however that brings it closer to a micro-kernel model, if no one else is allowed to change the kernel as shipped from factory, having everything else done in userspace. Additionally, if there is a userspace extension to an existing kernel extension, the userspace one will take precedence.

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jhbadger a day ago | parent | prev [-]

I don't know if it shares ancestry with the NextStep X server, but the one that used to be bundled with OS X (Xquartz) is still availsble for download (even on Tahoe) and I for one still keep it installed as I run various X11 based programs on my Macs.