And how would these computer have run DOS? Or Windows? The only OS available before 1994 or so that didn't use real mode code was OS/2. Did everybody switch over to OS/2? So how could Intel drop real mode? In fact, people's biggest complaint with OS/2 in the late 80's was OS/2 Compatibility Box: the way that it ran real-mode DOS programs. If people weren't willing to use an OS that allowed them to run a decent percentage of their old software, why would they use a computer that allowed them to run *none* of their old software!
Inside of a v8086 mode, like I mentioned. Remember, what I suggested was they went to only 2 modes. One solid v8086 mode which ran 8086 code well, and one protected mode which had it's own (clean) architecture.
It would not have been hard for Intel to produce a shell protected mode executive which did nothing but service v8086 mode code, as a reference. This would have allowed all the 8086 code to run (including DOS), and seeded innovation of OSs.
In this case Windows would have evolved using a cleaner architecture (the protected mode stuff) while all the old DOS code would still have ran fine. I'm not saying they would have made a better OS though!
One other point to run this into the ground: look at the success that Intel has had so far in changing their architecture with IA-64. We've been waiting for, what? 3 years now? And with what result?
Well, it would have been a much different situation making a move between 8086 and 286 and doing it right from the beginning, than ramming all that IA32 stuff into a new VLIW architecture. Woof.
In an environment as loose as the PC (as the author of Bochs I'm sure knows), anything that isn't 100% backward compatible is horribly frowned upon. Companies like Apple can change CPU designs with success because they control every detail of the hardware, OS and software. In the PC world, we aren't too open to that level of control.
Well, like I said, my plan was to give 100% compatibility for all the DOS progs. And provide a path to a new and clean architecture.
Besides that, I don't see anything 100% backward compatible about any of the x86 chips. The chapters on differences from the last chip are a joke. Try running misbaved programs.
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