On Wed, 17 Aug 2022 at 01:34, Wengier W via Freedos-user <freedos-user@lists.sourceforge.net> wrote: > > The apparent problems are the compatibility and quality. There are huge > differences between Windows 9x's MS-DOS prompt and (32-bit) Windows XP's > NTVDM.
Well, yes. The Win9x DOS prompt is real DOS running on a real DOS kernel which can access hardware. The 32-bit WinNT one can't: it's a sort of VM, containing a DOS emulator. The reason the NT one isn't very good is the reason that NT was a successful product: because it isolates apps from the hardware, making it more reliable and allowing SMP and things. This is akin to complaining that a motorcycle is a bad bicycle because this big heavy engine slows you down. The engine is the point of the exercise. If you don't use the engine then yes it gets in the way. > Even OS/2's MVDM did a much better job than XP's NTVDM in emulating DOS. Yes, it did. But I bought and ran OS/2. Running Fractint for DOS in an OS/2 DOS box, and then picking one of Fractint's extended screen modes, reliable crashed OS/2. It let apps hit the hardware. More compatible, but less stable. You can have one thing or the other. Not both, unless you time-travel 20Y forwards and emulate the entire computer in software. That's very inefficient and that itself offends my sense of elegance. :-) > The NTVDM only got worse with (32-bit) Windows Vista or 7 -- things such as > the full-screen mode were removed from its NTVDM as well. That is nothing to do with the VDM. That is because PCs were all getting 3D cards. Microsoft's devs (and Linux's devs) had no idea what to do with them. Apple's devs were smarter and worked out how to use a 3D accelerator to speed up a windowing desktop: what you do is, you render all the window contents as textures, and then you hand those textures to the 3D accelerator and ask it to render those textures onto flat rectangles on the screen. It's called display compositing, and Apple's implementation is called Quartz Extreme. Microsoft copied it in Vista. The display is a composited 3D scene rendered by the GPU. No frame buffer any more, and no way to switch between full-screen and window any more. Linux did the same, first with Compiz (AFAICR). But in Linux, the GUI is in a separate process from the kernel, so you can still switch back to text mode. Windows can't, because in NT4, Microsoft foolishly moved the GDI, the Graphics Device Interface, into the kernel. After NT4 the kernel is running in graphics mode all the time, and it was only about a decade later that MS realised this was a bad idea and started trying to disentangle them again. https://www.zdnet.com/article/microsoft-confirms-minwin-is-in-windows-7-after-all/ It only applies to server versions and it's only partial. > Meanwhile, 64-bit Windows XP (or higher) never had NTVDM in the first place. On x86, 64-bit Windows runs in x86-64 mode. x86-64 does not have VM86 any more. It has been removed. https://en.wikipedia.org/wiki/Virtual_8086_mode#64-bit_and_VMX_support Basically you have to run a full VM, or emulate it. > Clearly, Microsoft was trying to gradually eliminate the existence of DOS > from its Windows releases. It is not "clear" at all. It's part of the hardware design and MS has little influence over that. Remember, x86-64 is not even an Intel design: it is from AMD. Win64 drops 16-bit support. DOS is a 16-bit OS. It went along with 16-bit Windows support, no more and no less. -- Liam Proven ~ Profile: https://about.me/liamproven Email: lpro...@cix.co.uk ~ gMail/gTalk/FB: lpro...@gmail.com Twitter/LinkedIn: lproven ~ Skype: liamproven UK: (+44) 7939-087884 ~ Czech [+ WhatsApp/Telegram/Signal]: (+420) 702-829-053 _______________________________________________ Freedos-user mailing list Freedos-user@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/freedos-user
