Then you'd maybe get something like iOS, where the POSIX uid practically does not matter at all, and the strong security and separation is provided by other mechanisms like entitlements...

Someone else pointed out that BeOS allegedly had "quality and security" problems in general (I myself have no idea), so that may indeed have led to problems down the line, whereas BSD was pretty solid. But I agree with the OP and don't think POSIX security in particular is much of a factor today.

Yeah. Funny enough, if Apple had skipped OS X and gone directly to iOS, BeOS would have been a superior foundation. No uselessly mismatched security model or crusty legacy API baggage to clog up the new revolution in single-user always-online low-powered mobile devices.

Of course, that was in back in the days when an entire platform from hardware to userland could be exclusively optimized to utterly and comprehensively smash it in just one very specific and precisely targeted market. Which is, of course, exactly what the iPhone was.

Just as the first Apple Macintosh a decade earlier eschewed not only multi-user, multi-process, and even a kernel; every single bit and cycle its being being exclusive dedicated to delivering a revolutionary consumer UI experience instead!

In comparison, NeXTSTEP, which ultimately became iOS, is just one great huge glorious bodge. “Worse is Better” indeed!

..

Honesly, poor Be was just really unlucky in timing: a few years too late to usurp SGI; a few too early to take the vast online rich-content-streaming world all for its own. Just imagine… a BeOS-based smartphone hitting the global market in 2000, complete with live streaming AV media and conferencing from launch! And Oh!, how every Mac OS and Windows neckbeards would’ve screamed at that!:)

On a similar note, I've often wondered what Commodore's OS would have turned into. Not out of some misplaced nostalgia, just curiousity about the Could Have Been.

My guess is that by now in 2020, it would have at some point had an OSX moment where Commodore would have had to chuck it out, since both Apple and Microsoft have effectively done exactly that since then. Still, I'd love to peek into Amiga OS 9 descended from continual usage.

I think AmigaOS 3 could be a nice kernel as it is. And to make it more Unix-y memory protection could be introduced but only for a new userland process with more traditional syscalls.

It's a bit how DragonflyBSD is slowly converging to.

Amiga OS 9 would have looked very different from the Amiga OS that we know (I am talking from a developer's point of view, not about the GUI).

Since inter-process communication in Amiga OS was based on message passing with memory-sharing, it was impossible to add MMU-based memory protection later. As far as I know, even Amiga OS 4 (which runs on PowerPC platforms) is not able to provide full memory protection.

There was also only minimal support for resource tracking (although it was originally planned for the user interface). If a process crashed, its windows etc. would stay open. And nobody prevented a process to pass pointers to allocated system resources (e.g. a window) to other processes.

The API was incomplete and tied to the hardware, especially for everything concerning graphics. This encouraged programmers to directly access the hardware and the internal data structures of the OS. This situation was greatly improved in Amiga OS 3, of course far too late. Amiga OS 3 was basically two or three years too late. As far as I know, Apple provided much cleaner APIs, which greatly simplified later the evolution of their OS without breaking all existing programs.

Finally, the entire OS was designed for single-core CPUs. At several places in the OS, it is assumed that only one process can run at a time. This doesn't sound like a big issue (could be fixed, right?) but so far nobody has managed to port Amiga OS to multi-core CPUs (Amiga OS4 runs on multi-core CPUs, but it can only use one core).

I have been the owner of an Amiga 500 and Amiga 1200, but to be brutally honest, I see Amiga as a one-hit wonder. After the initial design in the mid-1980s, development of the OS and the hardware basically stopped.

> Since inter-process communication in Amiga OS was based on message passing with memory-sharing, it was impossible to add MMU-based memory protection later.

Why can't you do shared memory message passing with MMU protection? There is no reason an application in a modern memory protected OS can't voluntarily share pages when the use case is appropriate. This happens today. You can mmap the same pages, you can use posix shm, X has the shm extension...

Or just take a Docker-like approach, where each app thinks it is the only user and intra-app communication is where you put the security functionality

But the predecessor to containers were features like having daemons chroot into somewhere else and drop their uid to something that can't do much. That very much grew out of the Unix solutions. If Unix daemons were written for decades assuming all processes have equal privilege maybe we wouldn't see that.