Why is there a default monitor installed in Windows
Trying to remove a default monitor from Device Manager may be impossible due to Plug and Play capabilities.
This is an attempt to explain to non-techincal parties, the physical/chip related aspects. For XP and VISTA these are crutial to the original setup in those environments.
Windows is a GUI environment which requires a "driver" be installed so Windows can handle the device and assign it some form of control to create the GUI environment. As stated above that driver is NOT configurable, for a good reason.
The monitor attached AND the video adapter MUST be first be configured to work together. Allowing the setting of the default monitor COULD cause adaptor or monitor problems or actual damage for which Microsoft might be found liable.
Whereas, the generic defaults [the default display and adaptor/card] load the most limited information to start the system, and safely do so in *SAFE MODE* as well. Without the default, Windows could not be installed or a new device or monitor without adding the specific driver OR the OS installation immediately supplying generic support via some PnP driver. Instead the BIOS, adaptor, and the display all accept and provide a safe default base setting.
Microsoft and the video manufacturers deepened the dependance on OS compatibility and PnP, so generic aspects were added into the physical chips to provide the OS with the information necessary to properly place the device [IRQ and addressing if necessary] and the basic aspects and capabilities being provided. Over time, the on chip data of PnP devices has expanded to include numerous 'special' aspects in the coding, necessary for the device to perform increasingly complex functions, however, the base safety must be maintained. So video adaptors, monitors, and panels, provide that information when they first "talk" to the OS [2d-VESA - one eeprom/BIOS to another], as do other PnP devices. Adding a specific driver for the device then adds the extended functions supported [driving them].
There is ALWAYS a default monitor/display installed [640x480 60hz.], even though it may not show in Device manager, as that happens to be the safest range supported in the adapter and display [electric in America is at 60hz]. A flat panel MUST have a specialty driver/INF in 9X to supply the necessary information of its capabilities or it will literally burn out [monitors loose sync, though they also may be damaged].
Example using the 98SE registry, is at:
DEFAULT_MONITOR
PCI_VEN_10DE&DEV_0326&SUBSYS_00000000&REV_A1_BUS_00&DEV_0F&FUNC_00_1
the above providing the default to the nVidia driver
and at:
monitor
0001 {via monitor.inf}
though, since the monitor (Epson) did have an INF supplied with the OS and IS NOT PnP, installing that removes the visible default in Device Manager when used with the present adapter driver [at times the various versions of drivers did leave or want it there].
PnP video devices
When you connect your Plug and Play display/Panel/monitor, or when installing the driver for your panel or monitor, or when it is *discovered*, it leaves the default as fallback/safety as the device IS PnP [DDC capable] and apparently wants it there. IF it doesn't, then the programmers removed it, or the video adapter doesn't support PnP [which usually leaves the default installed unless its driver replaces it.].
Try this tool to test how and what is found (DDC), and see what it reports:
http://www.entechtaiwan.com/files/ddctest.exe
Removing the default display
IF you intend to try to over-ride this in a Plug and Play OS, then you MUST disable PnP/auto detection in the system;
AND if possible, the video adaptor;
AND ensure the INF does not contain any references to a default;
OR that it REPLACES the default driver [one already removed];
OR that it isn't added BY the driver itself once it is installed and first rebooted.
You would then have to remove the default monitor references from the registry/hive.
NOTE though, that the video device must then have the ALL the XP, VISTA, or 9X, installation and system/registry settings in its installation routine/INF, as if it was NOT PnP [9X term - XP/Vista uses different routines in its HAL and other].. that's ALL frequencies supported, registry entries, file placements/replacements, etc..
Also note that you will have disabled an OS safety feature which may cause your system to not be startable should something corrupt your system.
OTHER FACTORS FOR CONCIDERATION
- 1. ENTRIES in win.ini or system.ini
- 2. These driver files MUST take over [replace] the function of the *default monitor* in their INF or other during the installation process. Some drivers/INF install both.
- 3. A PlugnPlay monitor/display may AUTOMATICALLY make two entries [hard set in the actual chip - EEPROM via its DDC pins - EDID data], one {or more} for itself, and one for its fallback DEFAULT when it *talks* to the adaptor and OS during the discovery process. Removing either entry generally causes them to re-install as the function is performed at each boot, unless disabled {not recommended}. When discovery is turned off, or a corruption of the display settings or driver, or a bad re-set call from an application or game or other, may cause loss of functionality.
How about a page or two that EXPLAINS how Plug and Play works:
http://www.pcguide.com/ref/mbsys/res/pnp-c.html Gets to the point
http://en.wikipedia.org/wiki/Universal_Plug_and_Play Wiki's take on UPnP
http://www.upnp.org/ - Universal Plug and Play The base
And for the NT users:
http://support.microsoft.com/kb/323713
http://channel9.msdn.com/shows/Going_Deep MSDN - whats what...