This! Thats one of the most interesting things to me: Actually very often in the IT-world, the worst competitor won the race while better solutions were known and available: Microsoft, Intel etc.
Esp. that MS won for decades while making mainly a very bad OS, though they have some good enterprise products.
How would the world look, if Unix/BSD would have won this race?
I wouldn't say Unix itself is the best. It suffered a war between competing implementations pushing their own proprietary components. POSIX is the compromise.
But, ultimately, what is good about it today is not so much "Unix" (the proprietary OS from Bell Labs and its heritage), but specifically Linux and the BSDs. Why? Because they are actually open. They are freedom incarnate. You can add anything you like to them, today, without asking any permission. Not just their kernels, but their userlands too (Linux obviously varies by distro here). There's even a chance you can get your changes adopted upstream (unless it's GNOME), much more than you'd ever get from a proprietary company's OS.
So, while there's always room for improvement on the technical aspects of the OS, the social and political aspects of Linux and the BSDs make them the best we can achieve as a society.
What do you mean, which are the two? Sure, Windows is crappy by Linus and MacOS? They are both awesome.
Adding more features to OS is for some use cases a benefit, for other it's a barrier. For one it might be less work to get what you want ,for other it might be more code between you and hardware that just slows it down
Unix-like simplicity is exactly that, for some use cases directness is a benefit, for others it means extra work to do on top to get what you want.
If you just want a house, getting a raw foundation to work with is a lot to build on top, you have to bring the rest of the walls up yourself.
But if you want exactly the house you want, getting entirely different house to start with and changing it is far more work than starting from simple foundation and building up.
Overall unix "here is relatively simple operating system that doesn't force you but needs some things to be built on top to hit your use case" probably IS the best abstraction, despise not being "best" at really anything. There is reason we build houses from concrete and wood, and not carbon fiber and titanium alloys
Macs also existed but were expensive. The PC with DOS was both powerful and cheap.
More importantly, there’s backwards compatibility. By the time the 8086 came out, people had spent serious money on getting binary-only software (WordStar cost hundreds of dollars, for example). “Buy this computer, and you can keep running the software you paid for, but faster” was a good selling point.
Very few benefits to a clunky 24 or 20 bit word size; now it costs more and is a bizarre boutique architecture in a world where it needs to compete with 8 bit Z80s and 6502s.
The segment register solution does both almost for free in most cases. Code gets a segment, data gets a segment, stack gets a segment... and you are free to use all of memory if you bother to use the ES register. In many cases, that could be isolated to a small piece of the program so that was also quite cheap.
As someone who wrote code in assembler, Pascal, and C for those machines: it wasn't at all a nightmare. It was quite easy and simple.
We just have the illusion of a "flat" memory model, but it's not really flat, the CPU and the operating system does an important job in translating our flat memory model in something that is not flat at all. All that address translation work could have been avoided if we accepted to not have a flat memory model and be aware that our memory is divided in pages.
Basically we are doing in hardware the job of managing a non flat memory space that the programmer, or well, the compiler (or these days you would say the AI agent) could probably to better because it knows how to allocate things to avoid being them on page boundaries, and all of this to give the illusion to the programmer that it's working with a flat memory (except when it does something wrong and gets a segmentation fault, that, as the name suggests, is an hint that at the end the memory is not really flat).
The above is very similar to the argument that you should use a garbage collected langauge.
Back in 1980 most programs were being written in interpreted languages that did all the hard work of memory for you - just like today.
As an aside, the memory model is flat, it's just not physically linear when implementing virtual memory addressing.
When I think back I think it would be fun to have a hierarchical structure where composite data structures (think an array or hash map) are referred to with a pointer that goes into the segment register and you index inside a data structure with a regular pointer.
This code was a nightmare to port to protected mode 80286 so it went away by the Windows 3.1 era.
I was told not to waste any time with 80286 protected mode by all the experts I talked to. I can't complain a lot because that 80286 was crazy fast. Fast enough that when I got another job to develop some software for a teacher at my school I was able to run a Z80 emulator to develop for CP/M and get performance several times better than any real Z80!
I loved programming it too, the 286 had some 16-bit data paths that the 8086 didn't have which I took advantage of in assembly and in copy/move/zero routines that I used with Turbo Pascal which I thought was a much nicer language to C but when I got to college I switched to C because it was portable to the Sun 68k and later SPARC machines we had.
Also from a casual Google, an IBM PC launched in 1985 (picking the XT 5160-078 as an example) was around $4,995 at launch. Compare that to two 68000-based computers also launched in 1985: the Amiga 1000 launched at $1,295 and the Atari 520ST launched at $600.
These computer system prices - Sun, IBM, Commodore, Atari - came from the market segments the manufacturers aimed to sell to, rather than a cost saving enabled by cumbersome memory models.
The cumbersome memory model is just a historical accident; the 8086 designers wanted 8080 backwards compatibility so they could sell to former 8080 users, IBM did not require this. IBM would've picked the 68000 had it been "production ready" at the time, they did not reject flat memory on cost grounds!
By 1985, the PC AT (286) had already been out since August 1984. And the original XT was October of 1983. And the XT itself is literally the same as a PC with more expandability: 8 slots instead of 5, beefier PSU, room for a hard drive.
It's unclear if IBM or for that matter anyone would have been able to start designing a 68000-based machine and bring it to market by the fall of 1981. Sun brought the Sun 1 to market in May 1982, so about 9 months later, and with a much higher price.
And what did the Sun run? UNIX. What did IBM run? Quick ports of the last several years of CP/M software made possible because DOS 1 was specifically designed to implement a CP/M-like API, and the 8086 was specifically designed to allow porting of 8080 assembler code directly to small model 8086 code.
The PC was intended to be cheap and was competing with 8 bit machines. Being 16/20 bit made it already high end.
If you wanted 24 or 32 bit, IBM had many other machines to sell you. Or you could just buy a VAX.
Segmentation meant programs could remain essentially 16 bit with all the benefits to that like smaller code size.
