Talk:Virtual DOS machine

message: I'm sorry, but Windows XP does contain an NTVM.exe, located in the Windows system 32 directory.
[Timbo]
Another thing is that Vista must have some sort of 16 bit VDM because 16 bit applications developed at my work run on Vista (Beta). I understand MS doesn't support 16 bit on Vista but it works. Anyone got an idea why this might be?
:Wild guess: WoW/NTVDM happen to work in your beta build of Vista. Since Microsoft says 16-bit will not be supported in Vista, I'm guessing they'll remove them before shipping Vista. It may also be the case that WoW/NTVDM actually continue to work even in the final version of Vista (but without being installed), and MS just decides not to give any official support anymore. After all, it's not like they'll deliberately break support for 16-bit, they just don't want to have it hanging around their necks anymore. JRM · Talk 22:53, 14 July 2006 (UTC)
thread_title:  NTVDM presence 

message: It's not like M$ is deliberately dropping support for 16-bit apps in 64-bit Windows. It's the hardware (CPU) that simply does not support running 16-bit code while in 64-bit mode. M$ guys had no choice - it is simply impossible to natively run 16-bit code on a 64-bit x86 OS. - Anonymous 14:31, 23 May 2007 (UTC)
replies: text: Not correct: On pages 3-1 and 3-2 in "Intel's Intel® 64 and IA-32 Architectures Software Developer’s Manual Volume 1: Basic Architecture", they state that real mode and protected mode are still supported, and that a compatibility mode is available allowing a 64 bit OS to run 32 bit and 16 bit applications.  —CobraA1 21:49, 28 February 2008 (UTC)

text: Dosbox is not a virtualization application. It emulates a specific processor (386, 486, pentium, etc are available). 208.127.115.184 (talk) 01:23, 8 August 2015 (UTC)
thread_title:  Wrong! Wrong! Wrong! 

message: I have an old EGA Klondike solitaire card game that runs just fine on Vista Ultimate 32 bit on an Intel Celeron 530 "Core Solo" 64bit CPU. But on the AMD Athlon 64 LE-1620 running XP Pro SP3 32 bit, the game won't run due to an ntvdm error. So a 64 bit CPU can be designed to support 16 bit programs, but some designs are leaving out the features ntvdm relies upon. Bizzybody (talk) 04:25, 22 September 2010 (UTC)
replies: text: Just tried to run DUNE II on the AMD Athlon 64 LE-1620. Same error. This CPU simply does not support running DOS apps in XP. :( Now I need to check the Intel Core 2 Duo T5450 I upgraded my laptop with. Bizzybody (talk) 09:47, 22 November 2011 (UTC)
thread_title:  Works on Intel but not AMD 

message: The 16-bit NTVDM does not work under 64-bit windows, simply because microsoft did not port ntvdm to 64-bits.  In any case, they have a different virtual machine (connectix vpc), to handle 16-bit in virtual pc here.
--Wendy.krieger (talk) 11:15, 7 January 2011 (UTC)
thread_title:  Windows 64-bit and NTVDM 

message: The operating system can then perform an emulation and resume the execution of the DOS software.
This sounds a lot like what Wine does - and if Wines definition of emulator is correct, then some of the later word about emulation seems to be wrong.
E.g:
'only 80286 emulation was available. With Windows NT 4.0, 486 emulation was added'
This should maybe be changed to:
'only 80286 was supported. With Windows NT 4.0, 486 was supported.'
-- Actually its NOT like what windows does. An actual emulation of the 8086 processor takes place. It is microcode software inside the CPU that does the emulation, but it is still emulation.
62.242.204.166 (talk) 09:27, 29 September 2011 (UTC)
thread_title:  Is ntvdm an emulator or control layer? 

message: Wine's VDM is compatible with both 32-bit and 64-bit operating systems. However, due to utilization of long mode, 16bit applications did not run on 64-bit Linux kernel.
This is unclear. Does it work on 64-bit OSes or doesn't it? From my experience with Wine 1.0.1 on Debian x86_64, I am able to run 16-bit Windows programs that won't run on 64-bit Windows, but I was not able to run textmode DOS programs. The error was "winevdm: unable to exec 'C:\whatever': DOS memory range unavailable". When I successfully ran the 16-bit Windows program, it created a winevdm.exe in my process list. Best I can figure is winevdm uses VM86 mode for pure DOS programs, which makes it not work on 64-bit OSes. But it must do something else for 16-bit Windows programs. 24.218.3.18 (talk) 07:14, 18 May 2013 (UTC)
replies: text: Yes it does work although recently a sysctl variable was added to the kernel to block access to the LDT which is necessary for win16 to work with Wine.   — Preceding unsigned comment added by 2605:A000:BDC0:2000:7D5D:B2BF:849F:B10A (talk) 16:26, 31 October 2014 (UTC)
thread_title:  Wine VDM 

message: Hello.
The article currently says:
"NTVDM is a system component of all IA-32 editions of Windows NT family which allows execution of 16-bit Windows and DOS applications. It is not included with 64-bit versions"
I just removed "because virtual 8086 mode is not supported in long mode" because it is a form of original research known as synthesis of existing sources to advance a point. I do not contest that "It is not included with 64-bit versions" and I do not dispute that "virtual 8086 mode is not supported in long mode", especially since User:Matthiaspaul did add a source to that effect. What I contest is the "because" part. In other words, there is no source to tell if they are cause and effects.
Best regards,Codename Lisa (talk) 16:15, 3 July 2013 (UTC)
replies: text: It can't be the sole reason for one, because Microsoft could have just as easily ported the emulator for the RISC platforms to x64 and have 16-bit applications running that way. -- Liliana-60 (talk) 17:11, 3 July 2013 (UTC)
replies: text: That's true, given the fact that Windows 8 x64 is a hypervisor OS. Best regards, Codename Lisa (talk) 18:26, 3 July 2013 (UTC)
thread_title:  Support on 64-bit (again) 

message: Windows recognizes some 16-bit stub launchers/installers and converts (interprets?) them at runtime for use on 64bit processors. There's no mention of this in the article, and I'm not sure where it would go, so I'm just going to leave it here. Sources (microsoft): 64bit general,
outdated, XP/2003 specific 208.127.115.184 (talk) 01:32, 8 August 2015 (UTC)
thread_title:  16bit code on 64-bit Windows 

message: I actually came to the article for background and comparisons of the current options. One that I had already stumbled over is vDos, but it isn't mentioned here. Based on prior experiences, I'm pretty sure that FCBs are going to be relevant to my situation, but that topic is also missing from the article. (However there is a link to FAT that mentions FCB.) Shanen (talk) 08:14, 28 June 2023 (UTC)
thread_title:  What about vDos?