Mail Archives: djgpp/1999/07/23/15:42:42
> Christopher Nelson wrote:
>
> > DOS is an OS. therefore, if you write an OS, it cannot run under DOS.
e.g.
> > Windows 95 does not run UNDER DOS,
>
> Not to start a war, but it isn't 100% true, Windows runs over DOS and in
fact
> calls int 0x21. With the time Windows was evolving and uses DOS for less
things.
> NT is another history. If you don't beleive me just use any program to
trap
> DOS calls, Caldera did it.
> How do you think W95 can use hardware that only have a driver loaded in
> config.sys and no W95 driver ...
i think that they virtualize the interrupt table, see if the driver is
recognized, replace it with it's 32-bit cousin if so, or simply maintain the
boot-up config's v86 machine as a prototypical v86 machine, which is used to
spawn all future v86 machines and also used as a last-resort dispatching
mechanism to handle interrupt services that Windows simply doesn't
recognize.
if we're talking about Win3.x, it was never an operating system, it was an
environment. it worked on top of DOS, but still had the same basic
limitations as DOS did when you came right down to it. it used cooperative
multitasking because it couldn't pre-empt DOS. granted, it used less and
less of DOS, but it still had to have DOS to work. though there is alot of
holdover code, Win95 is a completely different beast where tasking,
loadiong, running, and device interface are concerned.
-={C}=-
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