Hi Jack,

> Thus far, I have been absolutely UNABLE to "break into" a V86 system,

VCPI is there to share protected mode, not to keep you outside.
But indeed while you are in V86, you have limitations. Running
your stuff in protected mode with HELP of VCPI would fix this,
but it is annoying to need TWO strategies - while there is no
V86, it is easy to have unlimited access and faster than even
shared protected mode with V86.

You can also "break" EMM386 itself by patching it in RAM but
I do not see why that would be good for you. Only debuggers
sometimes do this, for them it can be useful...

>> EMM386 only exists for backwards compatibility with EMS-using
>> software, and it was easier to implement due to the 386's MMU
>> (or whatever, I don't understand the details).   Sure, EMM286
>> exists in rare cases, but it's not as good.
> 
> I must DISAGREE:  EMM386 may have been written for "EMS" memory
> but it EVOLVED into Microsoft's protected-mode provider...

I disagree again - EMM386 got the VCPI extension so Windows and
EMM386 can cooperate instead of being in the way of each other.
Raw mode is as good as "VCPI mode" for Windows, because VCPI is
not giving you any fancy services. It just gives you a small set
of hooks and levers to share protected mode with EMM386. Windows
can even use the extra GEMMIS interface to clone the whole state
of EMM386 and effectively disable it and do memory management in
both Windows and DOS context itself, so Windows can avoid having
to share responsibilities with EMM386 and can avoid VCPI. Note:
Only very few EMM386 clones implement the low-documented GEMMIS.

What I mean: If there is no EMM386, very few apps will "feel bad"
about not having VCPI around. When protected mode is on - be it
EMM386 loaded or Windows running - then the spartan VCPI or the
helpful DPMI are needed by protected mode apps. DPMI also keeps
you further from hardware - you need less low level code and you
are kept away from it as well. Windows and Linux Dosemu therefore
give you DPMI but not VCPI. The CWSDPMI extender takes raw, VCPI
or DPMI situations as starting point for always giving you DPMI.

Eric


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