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Forums -> UltraMon™ SDK -> DirectX
Ralf Biederer   2005-05-02 17:18
I have a DirectX application which runs on multiple monitors using standard programming techniques.

I want to use more than the 10 monitors limit in XP, so I thought UltraMon can help.

Can it ? Is it compatible with DirectX ?

Thanks, Ralf
Christian Studer   2005-05-03 03:03
Please note that UltraMon only provides support for configuring more than 10 monitors (Windows Display Properties can only configure the first 10 monitors), but is not needed to use more than 10 monitors if your application handles monitor configuration.

I don't know if DirectX has any limits regarding the maximum number of monitors supported.

Christian Studer -
Ralf Biederer   2005-05-08 18:21
I just tested with 16 monitors under Windows XP (Matrox G450AGP DH, G450PCI DH, 3*G200PCI QUAD), UltraMon and DirectX works fine. I will setup 26 monitors (G450AGP DH + 6*G200PCI QUAD) just to see where the limits are and how the performance is...
( I need a bigger case vent and power supply for that so I can roast chicken on the case ;->> )

You said application can self-configure the monitors. For resolution and color depth I understand how. But DirectX needs the monitor to be active, but after initial installation it is not active. How could I do that programmatically or in the registry ?

One more thing : How can I change the monitor number ? I'd like to have them in a logical way for my application so I don't have to fiddle with the cables to get everything right. Can I change the monitor numbers in UltraMon ? For some reason Windows starts numbering with Dual Head cards first plug, then all QUAD cards, then DH cards second plug...
Christian Studer   2005-05-09 04:13
You could enable the monitors with UltraMon or via the ChangeDisplaySettingsEx API function.

UltraMon doesn't support re-numbering the monitors. I also doubt that this would work, the monitor numbers seem to be based on the device order or driver load order.

Christian Studer -
Ralf Biederer   2005-05-09 18:12
Thank you !

I would like to investigate a bit further regarding the monitor renumbering. Could you point me to the registry spot where windows stores information about monitors ? Must be one of those incomprehensible GUID subkeys...

If I find something useful I will let you know. I am sure that monitor renumbering is useful for any user with multiple displays ( and I am planning to work with 26... no typo, not 16... 26 is an interesting value because it gives a 5 x 5 array plus the primary control monitor)

BTW : with a large number of monitor the UltraMon configuration screen becomes awkward to use because it does not scroll but instead minimizes the monitor icons. Finally the are so small that they disappear...
Christian Studer   2005-05-10 10:03
The hardware stuff is stored under HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet. As far as I know the monitor numbers aren't stored, and are determined dynamically based on the installed video cards.

BTW, you might get weird errors when installing more than 16 monitors, see this thread for more information.

Support for scrolling will be considered for UltraMon 3. As a workaround, you could select the monitor via the drop-down list, and position it by entering the position coordinates directly.

Christian Studer -
Ralf Biederer   2005-05-17 02:51
OK, there seems to be a limit in the number of PCI cards. I can only install 4 PCI Matrox boards.
DEpending on PCI slot the 5th will get yellow exclamation marks or even bluescreen.

So I see 18 monitors in the UltraMon Desktop with 4 G200QUAD and a G450AGP DualHead.

However Ultramon seems to have a problem. On startup of the PC I get the Windows error "Ultramon Desktop hat einen Fehler verursacht und muss beendet werden".

The strange problem is that the 18th monitor cannot be activated. And it is not the 18th monitor in Windows counting, it is the 5th, which happens to be the 4th on the first QUAD card.
When I try to activate it ("√úbernehmen") the mouse disappears for 30 seconds or so and on return of the mouse the monitor will be deactivated again.

In the Windows hardware manager there is no error, everything seems normal. The PC is also not overloaded, all fine.

So I have 17 usable monitors, which is 1 more than I expected. However, for the 18th, I guess it's Ultramon that swallows it.
Christian Studer   2005-05-17 03:21
The UltraMonDesktop.exe crash is due to an issue with GDI+, the next release will have a workaround for this.

The problem is that some versions of GDI+ cause an exception during shutdown when a large number of monitors is installed.

Regarding the 18th monitor, most likely the monitor can't be enabled due to a resource issue, or maybe a limitation of the video card driver.

Christian Studer -
Ralf Biederer   2005-05-17 04:05
I did some more testing, and now the Ultramon Desktop crash happens everytime I try to access one of the additional monitors (currently trying with #2). This does not happen during shutdown, and it did not happend with 16 monitors installed.Actually the system does not complete shutdown at all, but that doesn't bother me. The production system shall never shutdown anyway, and Windows is known for shutdown problems since at least W98B...

I will need to remove the 4th QUAD card and substitute with a Dualhead card for the time being (and hoping I will get an early beta release of the fixed version ?? ;->).

Do you think it'll help if I deinstall UltraMon again, would that let me access the 17 monitors (or maybe all 18 ?)

I could install MSVC remote debugging on my machine and let you debug ?
Ralf Biederer   2005-05-17 04:19
Yep, verified. With a total of 16 physical monitors in the systems I can access all screens again.

When I deactivated the 17th monitor with the QUAD card I got a black primary screen. I then replaced the 4th QUAD with a DUAL.

I could lend you 4 QUAD cards and an AGP DUAL for testing ? I really need the 17 monitors working (4*4 matrix + primary). I already gave up on the 26 ;-<<<
Christian Studer   2005-05-17 04:22
You could disable automatic wallpaper refreshing under Wallpaper > Options (uncheck 'adjust wallpaper when display configuration changes').

This way you'll no longer get the UltraMonDesktop.exe crash when enabling a monitor.

The exception is raised during GDI+ shutdown, not system shutdown. UltraMonDesktop.exe shuts down GDI+ after it has done its work, so it's not really a problem, just a bit annoying.

Christian Studer -
Christian Studer   2005-05-17 04:28
Thanks for the offer, but the problem isn't with UltraMon. If the monitor can't be enabled, it's most likely due to not enough free resources, or a limitation in the video card driver.

UltraMon itself has no hardcoded limits, I have tested with more than 30 monitors (virtual monitors, not real hardware), and haven't noticed any UltraMon-related issues.

Keep in mind that multi-monitor support is still provided by the operating system/video card driver, not by UltraMon. UltraMon only gives you a user interface for configuring the monitors.

Christian Studer -
Ralf Biederer   2005-05-17 05:53
Thanks, it helped. I have 17 monitors active.
I just ran my app on #18 !

#5 can't be enabled.

When I run "Monitor identifizieren" in UltraMon I see an overlay of #6 and #12.

Any ideas on that ?
Christian Studer   2005-05-18 04:16
I'm not sure what would cause this, please post the system information from the About dialog (UltraMon menu > About or UltraMon menu > Info).

Christian Studer -
Detlef   2006-10-08 21:25
Hallo Ralf, ich bins Detlef (EX-Fidelio) melde dich doch mal. hatten lange keinen Kontakt, schade eigentlich
Forums -> UltraMon™ SDK -> DirectX

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