That would be surprising. Where do you get that? I don't mean toy OSes or experiments. Linux, MacOS and Windows are still in development and I can't imagine the number of hours invested.
> they use existing libraries and the like
Where can I find out about that? Thanks.
It's not like Fuschia was supposed to be a "fully capable OS developed from scratch", either? I mean it's "just" the kernel and other low level components, most of the software stack would remain same as Android/Linux at least for the time being.
Ok, I'll bite. If we're talking classic Macintosh OS, perhaps.[0] macOS? No way. The first Mac OS X was released in 2001, and was in development between 1997 and 2001 according to Wikipedia.[1] But the bulk of the OS already existed 1997. Mac OS X was a reskin of NeXTStep. NeXTStep was released in 1989, final release 1995, final preview 1997 (just before Apple sold out to NeXT).[2] NeXTStep was in production for quite some time before the x86 version shipped (around '95 from memory). In case you are wondering, I can assure you that NeXTStep was a very capable OS. NeXTStep was in development for a couple of years before the first hardware shipped in 1989. NeXTStep was built on top of Mach and BSD 4.3 userspace. Mach's initial release was 1985.[3]. Not sure how long the first release of Mach took to develop. You can check BSD history yourself. But I'd say, conservatively, that macOS took at least 14 years to develop.
[0] check https://folklore.org/
[1] https://en.wikipedia.org/wiki/Mac_operating_systems
If you mean the early 1980s OS, that is not comparable. It probably ran in something like 512K of memory off of a 5.25" floppy disk (or a tape?).
> It's not like Fuschia was supposed to be a "fully capable OS developed from scratch", either? I mean it's "just" the kernel and other low level components
I don't know the answer, but doesn't the second sentence describe Linux?
In comparison, the Lisa OS required 1MB RAM and a 5MB hard disc, hence the eye watering $10,000 introductory price.
Development on the Mac apparently started in 1979, and release in 1984 although the early Jeff Raskin era machine was quite different to the final Steve Jobs led product.
