# Mirror driver

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> Source: https://en.wikipedia.org/wiki/Mirror_driver
> Source revision: 1325177164
> License: Creative Commons Attribution-ShareAlike 4.0 International (https://creativecommons.org/licenses/by-sa/4.0/)

A **mirror driver** is a [display driver](/source/Device_driver) for a virtual device that mirrors the drawing operations of one or more additional physical display devices.

When video mirroring is active, each time the system draws to the primary video device at a location inside the mirrored area, a copy of the draw operation is executed on the mirrored video device in real-time.[1]

Windows' mirror drivers were first introduced in 1998 with the Windows 2000 display driver model, which was renamed later to XPDM. In 2006, for [Windows Vista](/source/Windows_Vista), Microsoft introduced a new [Windows Display Driver Model](/source/Windows_Display_Driver_Model). The older drivers were still supported under Vista, but since the older model did not encompass support for features first introduced with Vista, those newer features would necessarily be disabled when an older driver was active. As a consequence, when a mirror driver designed for the older model was active, such as when [Windows Remote Assistance](/source/Windows_Remote_Assistance) or [Windows Live Mesh](/source/Windows_Live_Mesh) were in use, Vista disabled [Desktop Window Manager](/source/Desktop_Window_Manager) and [Windows Aero](/source/Windows_Aero).[2] A similar situation existed with the transition from [Windows 7](/source/Windows_7) to [Windows 8](/source/Windows_8). Beginning with the [DDK](/source/Driver_development_kit) targeted at Windows 8, mirror drivers have to fulfill very exacting specifications - they must support a specific set of functions, and no more than those.

Windows installations come with two mirror drivers preinstalled - "mnmdd" used by NetMeeting, and "RDPDD Chained DD" used for Terminal Server/RemoteDesktop services. Third-party mirror drivers are included with [screen readers](/source/Screen_reader) such as [JAWS](/source/JAWS_(screen_reader)), [Window-Eyes](/source/Window-Eyes) and FreedomBox; the monitoring software [LanSchool](/source/LanSchool); and [remote desktop software](/source/Remote_desktop_software) such as [Timbuktu](/source/Timbuktu_(software)), [LogMeIn](/source/LogMeIn), [UltraVNC](/source/UltraVNC), [TightVNC](/source/TightVNC), Radmin and RemotePC.

## References

1. ["Windows Driver Kit: Glossary"](http://msdn2.microsoft.com/en-us/library/ms789543.aspx). Microsoft Developer Network.

1. Campbell, Matt & Calvo, Mike (2008-03-21). ["The Facts About Mirror Drivers in Assistive Technology"](http://serotek.com/mirror-driver-paper.html). Retrieved 2015-06-05.

## External links

- [MSDN Library - Mirror Drivers article](http://msdn.microsoft.com/en-us/library/ff568315.aspx)
- [UltraVNC Mirror Driver](https://uvnc.com/products/mirror-driver.html)
- [Mirror Driver for TightVNC](http://www.demoforge.com/dfmirage.htm)

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Adapted from the Wikipedia article [Mirror driver](https://en.wikipedia.org/wiki/Mirror_driver) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/Mirror_driver?action=history)). Available under [Creative Commons Attribution-ShareAlike 4.0 International](https://creativecommons.org/licenses/by-sa/4.0/). Changes may have been made.