We develop an XP Display Driver that is running on top of hardware without VGA capabilities. We’ve recently stumbled across the following problem. Windows stops calling our driver when a CMD console window is switched to a fullscreen mode. After switching back to a normal CMD window with Alt-ENTER our driver is called again to render and everything is working fine again.
It seems like Windows starts using the VGA driver to render the full screen command prompt to support legacy DOS applications. Does anyone know if there is a way to disable full screen DOS support in XP?
We develop an XP Display Driver that is running on top of hardware without VGA capabilities. We’ve recently stumbled across the following problem. Windows stops calling our driver when a CMD console window is switched to a fullscreen mode. After switching back to a normal CMD window with Alt-ENTER our driver is called again to render and everything is working fine again.
It seems like Windows starts using the VGA driver to render the full screen command prompt to support legacy DOS applications. Does anyone know if there is a way to disable full screen DOS support in XP?
Yes, fullscreen mode enters character mode display. Not sure how to disable it, though the TS display driver does so effectively (you’ll get something to the effect of a “mode not supported” error, or something of that sort if you try to fullscreen a console over RDP, IIRC).
Perhaps investigating how that denial process works might be one option to persue.
(N.B. I would uninstall any app that tried to break fullscreen character mode on any of my boxes - it’s not a nice idea.)
S
-----Original Message-----
From: xxxxx@panologic.com Sent: Wednesday, October 08, 2008 12:44 To: Windows System Software Devs Interest List Subject: [ntdev] How to disable full screen DOS prompt in XP
We develop an XP Display Driver that is running on top of hardware without VGA capabilities. We’ve recently stumbled across the following problem. Windows stops calling our driver when a CMD console window is switched to a fullscreen mode. After switching back to a normal CMD window with Alt-ENTER our driver is called again to render and everything is working fine again.
It seems like Windows starts using the VGA driver to render the full screen command prompt to support legacy DOS applications. Does anyone know if there is a way to disable full screen DOS support in XP?
We develop an XP Display Driver that is running on top of hardware without VGA capabilities. We’ve recently stumbled across the following problem. Windows stops calling our driver when a CMD console window is switched to a fullscreen mode. After switching back to a normal CMD window with Alt-ENTER our driver is called again to render and everything is working fine again.
It seems like Windows starts using the VGA driver to render the full screen command prompt to support legacy DOS applications.
Correct. It has always done so. It HAS to; your driver doesn’t know
how to shift the screen into real VGA mode 12.
Does anyone know if there is a way to disable full screen DOS support in XP?
Well, it’s time to step into the “way back” machine. When NT 3 and 4
used to run on non-x86 platforms, those machines did not have VGAs. In
that case, Alt-Enter brought up a dialog box saying “sorry full screen
is not supported”. However, I do not remember what triggered that. My
guess is you need to disable the standard VGA driver in some way. You
might need to do a little registry hacking.
–
Tim Roberts, xxxxx@probo.com
Providenza & Boekelheide, Inc.
Right now we see the desktop rendering freezes completely until pressing Alt-ENTER (going back to the normal desktop rendering). Getting the “The video device failed to initialize for fullscreen mode” message from Windows is certainly an improvement for now. This message can be triggered when trying to switch to a full screen DOS prompt in an RDP session. The question really is how to tell Windows that the fullscreen DOS support should be disabled.
No. DOS apps can’t force that switch. It has to be done using
Alt-Enter, and almost no one today even remembers that option exists.
Media Player also has a mode where it can use a real VGA mode, and that
would also be disabled, but again most people don’t even know that’s
available.
–
Tim Roberts, xxxxx@probo.com
Providenza & Boekelheide, Inc.
All I meant was that breaking something a user uses - however infrequently - to support a limitation of your personal product
doesn’t seem very charitable. I assume that’s how the dev found out about the problem, and it doesn’t sound like fullscreen
actually causes his driver any problems, other than that it doesn’t use his driver, so I don’t see any upside for the user, even
though in practice, absolutely, this is not a common request.
mm
Tim Roberts wrote:
Martin O’Brien wrote:
> Wouldn’t that break existing user’s applications?
No. DOS apps can’t force that switch. It has to be done using
Alt-Enter, and almost no one today even remembers that option exists.
Media Player also has a mode where it can use a real VGA mode, and that
would also be disabled, but again most people don’t even know that’s
available.
Taking a quick look it seems that this will not be easy to stop with legal
manners because it appears that this functionality is provided not by the
standard VGA driver but by the VGA boot driver BOOTVID.DLL. This module does
not create any device objects that you can attach to or filter. The NTOSKRNL
Inbvxxx and the HAL functions which export the native screen functions
appear to be wrappers which call into BOOTVID.DLL directly.
//Daniel
wrote in message news:xxxxx@ntdev… > We develop an XP Display Driver that is running on top of hardware without > VGA capabilities. We’ve recently stumbled across the following problem. > Windows stops calling our driver when a CMD console window is switched to > a fullscreen mode. After switching back to a normal CMD window with > Alt-ENTER our driver is called again to render and everything is working > fine again. > > It seems like Windows starts using the VGA driver to render the full > screen command prompt to support legacy DOS applications. Does anyone know > if there is a way to disable full screen DOS support in XP? > > Thanks in advance, > Alex > >
Taking a quick look it seems that this will not be easy to stop with
legal manners because it appears that this functionality is provided
not by the standard VGA driver but by the VGA boot driver BOOTVID.DLL.
This module does not create any device objects that you can attach to
or filter. The NTOSKRNL Inbvxxx and the HAL functions which export the
native screen functions appear to be wrappers which call into
BOOTVID.DLL directly.
I don’t think that is correct. I could be mistaken, because I last
looked at this a very long time ago, but at the time I was doing display
drivers, Windows actually created a new instance of vga.sys to handle
full-screen DOS boxes. Alt-Enter caused it to suspend the hi-res driver
and activate vga.sys. It wasn’t bootvid.dll.
–
Tim Roberts, xxxxx@probo.com
Providenza & Boekelheide, Inc.
> From: xxxxx@panologic.com > Subject: [ntdev] How to disable full screen DOS prompt in XP > To: “Windows System Software Devs Interest List” > Date: Wednesday, 8 October, 2008, 11:14 PM > We develop an XP Display Driver that is running on top of > hardware without VGA capabilities. We’ve recently > stumbled across the following problem. Windows stops calling > our driver when a CMD console window is switched to a > fullscreen mode. After switching back to a normal CMD window > with Alt-ENTER our driver is called again to render and > everything is working fine again. > > It seems like Windows starts using the VGA driver to render > the full screen command prompt to support legacy DOS > applications. Does anyone know if there is a way to disable > full screen DOS support in XP? > > Thanks in advance, > Alex > > > — > NTDEV is sponsored by OSR > > For our schedule of WDF, WDM, debugging and other seminars > visit: > http://www.osr.com/seminars > > To unsubscribe, visit the List Server section of OSR Online > at http://www.osronline.com/page.cfm?name=ListServer
“Tim Roberts” wrote in message news:xxxxx@ntdev… > I don’t think that is correct. I could be mistaken, because I last > looked at this a very long time ago, but at the time I was doing display > drivers, Windows actually created a new instance of vga.sys to handle > full-screen DOS boxes. Alt-Enter caused it to suspend the hi-res driver > and activate vga.sys. It wasn’t bootvid.dll. >
I’m possibly wrong, I only looked at the way blue screens were produced, not at full screen console windows which seem to have disappeared now.
“Tim Roberts” wrote in message news:xxxxx@ntdev… >> I don’t think that is correct. I could be mistaken, because I last >> looked at this a very long time ago, but at the time I was doing display >> drivers, Windows actually created a new instance of vga.sys to handle >> full-screen DOS boxes. Alt-Enter caused it to suspend the hi-res driver >> and activate vga.sys. It wasn’t bootvid.dll. >> > > I’m possibly wrong, I only looked at the way blue screens were > produced, not at full screen console windows which seem to have > disappeared now.
Yes, you are 100% correct about blue screens. They use bootvid.dll, completely out-of-band. The full-screen DOS box is quite a different mechanism.
– Tim Roberts, xxxxx@probo.com Providenza & Boekelheide, Inc.
Martin O’Brien wrote:
> Wouldn’t that break existing user’s applications?
No. DOS apps can’t force that switch. It has to be done using
Alt-Enter, and almost no one today even remembers that option exists.
A few of us old-school folks do. I actually have a copy of the original
King’s Quest I (4-color CGA, PC speaker) working on my Vista dual-core
x64 with 24" widescreen. Awesome.
Vista x64 drops ntvdm and full screen console support, however, so you must be using a third party emulator that does not switch to true hardware character mode if you are really on an x64 OS build.
S
-----Original Message-----
From: Stephen Cleary Sent: Monday, October 13, 2008 08:44 To: Windows System Software Devs Interest List Subject: Re: [ntdev] How to disable full screen DOS prompt in XP
Tim Roberts wrote: > Martin O’Brien wrote: >> Wouldn’t that break existing user’s applications? > > No. DOS apps can’t force that switch. It has to be done using > Alt-Enter, and almost no one today even remembers that option exists.
A few of us old-school folks do. I actually have a copy of the original King’s Quest I (4-color CGA, PC speaker) working on my Vista dual-core x64 with 24" widescreen. Awesome.
Yes. It does use the same shortcut, though, for backwards compatibility.
Actually, the emulator uses DirectX to draw the CGA graphics, intercepts
the PC speaker signals and translates them to WAV, and also handles the
timing difficulties.
I just love playing extremely old games on my large monitor.
-Stephen Cleary
Skywing wrote:
Vista x64 drops ntvdm and full screen console support, however, so you must be using a third party emulator that does not switch to true hardware character mode if you are really on an x64 OS build.
S
-----Original Message-----
From: Stephen Cleary > Sent: Monday, October 13, 2008 08:44 > To: Windows System Software Devs Interest List > Subject: Re: [ntdev] How to disable full screen DOS prompt in XP > > > Tim Roberts wrote: >> Martin O’Brien wrote: >>> Wouldn’t that break existing user’s applications? >> No. DOS apps can’t force that switch. It has to be done using >> Alt-Enter, and almost no one today even remembers that option exists. > > A few of us old-school folks do. I actually have a copy of the original > King’s Quest I (4-color CGA, PC speaker) working on my Vista dual-core > x64 with 24" widescreen. Awesome. > > -Stephen Cleary
Philip D. Barila
Seagate Technology LLC
(720) 684-1842
As if I need to say it: Not speaking for Seagate.
“Stephen Cleary” wrote in message news:xxxxx@ntdev… > Yes. It does use the same shortcut, though, for backwards compatibility. > > Actually, the emulator uses DirectX to draw the CGA graphics, intercepts > the PC speaker signals and translates them to WAV, and also handles the > timing difficulties. > > I just love playing extremely old games on my large monitor. > > -Stephen Cleary > > Skywing wrote: >> Vista x64 drops ntvdm and full screen console support, however, so you >> must be using a third party emulator that does not switch to true >> hardware character mode if you are really on an x64 OS build.
