🚀 go-pugleaf

In article <37619@uflorida.cis.ufl.edu>, ggh@reef.cis.ufl.edu (Greg Huey - Aymer deGregory) writes:
> 
>   Im trying to write a 'bare-bones' multi-processing os for the 386.
> I dont wont to create my own dos, obviously I want to use MS-DOS...
> Question is, how do I do this in protected mode?
>   Presumably, I create the GDT, LDTs, TSSs, IDTs, and the viarious gates...
> But no matter HOW I map virtual memory with the GDT, LDTs, I cannot make
> the virtual memory transparent, due to the priv bits and table indicator
> bit. I need to put the 386 in protected mode, but it has to look the
> same to MS-DOS, otherwise MS-DOS will fail, wont it? For instance, MS-DOS
> knows one of its buffer is at seg:offs -- when I put the 386 into protected
> mode, seg, rather than being a simple address, will now be treated as a
> selection index into the GDT or LDT.

As I understand it, V806 mode was created just to enable running DOS
apps (really 8086 apps) while a supervisor protected mode program 
watches everything.

I you try to run DOS in true protected mode, I think you're out of luck.
Notice that all major task-switching or multitasking systems do the same:
they put each DOS session in a separate V8086 session.
 
robert