Is MS-DOS, PC DOS and DR-DOS vintage enough to count?

[John Willis]

>
> Exactly! This!
>
> All versions of W9x run in 386 protected mode, with DOS sessions in
> the 386's Virtual 8086 mode.
>
> There was no difference that I'm aware of between them.
>
> Between WfWg 3.11 and 9x, yes. Between 9x and NT, yes. But 95/98/ME, no,
> TTBOMK.
>
> If there _was_ some difference, [a] it was lept _very_ quiet, and [b],
> I want to know!
>
>
I wrote at some length about these differences at:

https://youngmumpster.wordpress.com/2013/10/13/windows-multitasking-a-historical-aside/

a few years ago.