Our contribution: X-META-X

This installation became the first killer application for our X-META-X product. X-META-X comprises a base product and several options. In fact some of the options were requested by and developed for this site.

The main request was to copy the contents of an arbitrary screen of one of the workstations onto a large wall display. This should ease communication between the operators during emergency situations.

Mirroring is the base functionality of the X-META-X proxy. It maps one or more virtual screens arbitrarily on one or more real screens of multiple X Window servers. Here the real screens are the three heads of a workstation and the wall display. Due to the unique proxy principle the applications connect to the X Window display as usual, without any modification.

Because the wall display operates with a higher resolution (1,920 × 1,440 pixels) than a standard workstation screen (1,280 × 1,024 pixels) the session display has to be scaled up with a different aspect ratio (4 to 3 vs. 5 to 4) by the VARIO option of X-META-X. However, this is not done pixel by pixel, but all X Window requests are scaled appropriately, giving a correct, complete and pleasant display of all vector graphics, pixel graphics, and fonts.

The mouse pointer image is difficult to find on the high resolution wall display. Therefore the X-META-X proxy is configured to zoom the cursor image by two.

Emergency needs simple, precise, direct communication and immediate overview. In an emergency situation the operator's session is "beamed" to the wall display replacing the session displayed formerly (see above, second screen from left). The operator continues to control the applications on his workstation. The DYNAMICSERVER option of X-META-X allows to dynamically modify the mapping of virtual screens on real screens without disturbing the X Window session. This configuration change is done by the xmetaxtool program which is called by the GUI of the system control. Therefore the mirroring may be bound to an alarm, too.

Emergency needs immediate reaction. When mirroring, normally all X Window resources are copied from the workstation to the X Window server controlling the wall display yielding delays not acceptable in an emergency situation. To eliminate the delay all screens of a workstation are constantly displayed on the wall display in mutually totally overlapping windows (the INWINDOW option of X-META-X is needed). Therefore the resources of all three screens of a workstation are constantly hold on the wall display. When the operator needs another screen mirrored, the corresponding window on the wall display is simply brought to the foreground without any delay. Depending on the memory resources of the wall display X Window server this principle may be extended to all seven workstations.

Emergency needs high availability. The FAILSAFE option lets the X-META-X proxy detect the failure of an X Window Server. The corresponding screens are deleted from the configuration automatically without terminating the X Window session. Thus, in Lenzhard the break-down of the wall display or the network connection to the display does never disturb the critical applications.