7.9. Stopping the screensaver¶
Screensavers have long lost their importance on corporate desktop computers since power saving features have been introduced in modern CPUs and chipsets and since enterprises have started to realize that wasting energy with desktop computers running screensavers is a significant cost factor. Nevertheless, screensavers are still a supported operating system feature and a number of enterprises still have their corporate desktops running with screensavers enabled. A screensaver is nothing else than a standard Windows® executable that runs on a special desktop named “Screen-saver”. If this desktop is shown after a period of user inactivity on the current desktop, neither IDERI note messages on the Windows® logon screen nor any IDERI note messages on the user desktop or the Windows® 10 user lock screen can be noticed by any passersby looking on the screen.
Stopping the screensaver is disabled by default on computers running Windows® server operating systems
The feature described in this section has no benefit when being enabled on a Windows® Terminal Server, but rather contributes unnecessarily to system load. Stopping the screensaver on computers running a Windows® server operating system is therefore disabled by default. On server computers that are running in single-user terminal services mode or on standalone servers that are used much like a Windows® workstation, this feature can be enabled by setting the “ServerOverrideWLN” registry DWORD value (see table inotecln.exe Registry Values) to a non-zero value. At installation time the MSI property SERVER_OVERRIDE_WLN (see table intclnt.msi MSI properties) can be used to activate this feature.
The IDERI note client can be configured in such a way, that it attempts to interrupt a running screensaver if messages are pending that can be made visible by interrupting the screensaver. A naïve approach to this problem would be to simply disable the screensaver or prevent it from running while messages are pending. But this ignores one of the main purposes of a screensaver: Typically on corporate desktops with screensavers activated, screensavers are configured to be “secure screensavers”. A secure screensaver does not allow any interaction with the logged in user’s desktop after the screensaver is terminated by subsequent user interaction, but instead requires reauthentication on the Windows® logon screen. This behaviour of an automatically locked user desktop session is a mechanism that users rely on and which relieves them from manually locking their desktop e.g. before leaving their desktop unattended. Preventing the screen saver from running while an IDERI note message is shown on the users desktop would impose a major security risk for users with the natural expectation that their computer sessions be locked automatically by virtue of the screensaver starting after a few minutes.
Therefore the IDERI note client’s screensaver interruption functionality leaves screensaver settings untouched and does not prevent the screensaver from running if a message is pending. Instead, the IDERI note client attempts to detect a running screensaver after it has started and only tries to interrupt it if this can make a pending message or notification visible to passersby watching the screen, e.g. by having it shown on the Windows® 10 user lock screen or the Windows® login screen.
Since detection of a running screensaver requires additional CPU resources and since screensavers on corporate desktops have become a marginal phenomenon, interrupting screensavers is not enabled by default in the IDERI note client standard configuration. You should only enable screensaver detection and interruption for the IDERI note client and ticker if your client computers running the IDERI note client actually run with screensavers activated. The screensaver interruption functionality is controlled by the two “ScreensaverStop” DWORD registry values for IDERI note message windows (see table inotecln.exe Registry Values) and the IDERI note ticker (see table inotickr.exe Registry Values) and can be controlled at installation time using the MSI properties “SCREENSAVERSTOPCLIENT” (see table intclnt.msi MSI properties) and SCREENSAVERSTOPTICKER (see table MSI properties for the IDERI note ticker).