Multi monitor

The term multi-monitor , and multi-head as a short form of multi-head computer , multi-screen computer ( multi-screen computer ), multi-display computer or multi-monitor computer , refers to a computer that takes over a screen about two ( dual screen computer / dual-head computer ) or more screens. Multi-Head can also include visualization via multiple video projectors , televisions or other display devices such as an interactive whiteboard . In any case, a multi-head graphics card with multiple video outputs or multiple graphics cards is required in the computer.

Operating modes

This technology can be used in a number of ways. The work surface may be one or can be enlarged to form a coherent, virtual desktop multiple screens, which show respectively a section of the surface ( Expand / tensioning / Expand displayed more than once), the screens are displayed different, independent spending or the same image ( duplicate / Clone ), for example for presentations in separate rooms.

Area expansion

It is possible to combine several screens into a vertical or horizontal area, whereby the screens are addressed with the same resolution. For the software including the operating system, it looks like there is only one screen. The advantage is the resulting performance, but the disadvantage is that screens usually have wide frames that are in the middle when a program is maximized. This type of display is therefore of particular interest for frameless displays with identical size and resolution or when the screens can be divided by software.

Desktop extension

Multi-Head in action at a parquet workstation on the Frankfurt Stock Exchange

Since Windows 98 it has been possible to expand the working area with several monitors connected in parallel under Windows . Also Unix derivatives offer under the name Xinerama in conjunction with the X Window System that possibility, with special X server extensions as Chromium even a distributed OpenGL allow -3D acceleration. The function has been implemented in Linux since xfree86 version 4.

This configuration is often used by graphic designers and programmers in order to take advantage of the drag-and-drop functionality of the operating system. But also in areas such as CAD drawing, the stock exchange, air traffic control, medicine or science, more than just one monitor is very often used for the separate, clear display of the data.

Usually one has an application program on one screen and a file directory or an image browser on the second monitor, via which documents or text fragments are dragged into the application. There is no need to switch between the overlapping windows, which speeds up parallel work with several programs. For screen and web designers in particular, the division of space between two smaller monitors is often much cheaper than that of a very large monitor. In addition, two or more monitors offer web designers the option of a simple color proof: The monitors are set with different contrast and brightness values in order to check the display on different, mostly non-calibrated end devices.

With many programs, the tool palettes can be moved from the main window to the second monitor, which enables a clearer display and enlargement of the actual work area. The use is like a monitor that has been divided into two monitors. With the X Window System it is also possible to operate several desktops in parallel for each monitor. For example, the work area of one monitor can be completely adapted to the specific task without causing system-wide changes.

Unlike area expansion, the software is aware of the presence of multiple screens. One of them is the main screen - most programs are first started there or on the screen with the mouse pointer. If programs are maximized, they are only maximized on the screen on which they are currently located. Programs that are not maximized can span multiple screens. In that case, it is desirable to use screens with the same pixel density. However, since windows are usually only on one screen, different screens can easily be mixed for desktop expansion.

Nvidia called the desktop extension DualView under Windows XP it is called attaching referred.

Multi-screen operation

In contrast to expanding the desktop with additional screens, it is possible to show the same or different output on several screens. Either the content of the (main) desktop is replicated, i.e. displayed unchanged on all other screens, or something else is displayed. The latter mode is particularly interesting for presentations: The speaker can see the presentation including the comments on the main screen (e.g. the laptop monitor), while only the uncommented presentation slides are visible on the video projection - which is only visible to the viewer.

The easiest way to connect multiple monitors is with multi-head graphics cards. While cards for up to four monitors are standard today, individual graphics cards for up to 16 monitors are available in the higher price segment. AMD calls the function introduced with the HD-5000 series of controlling more screens (depending on the model, a maximum of three to six), Eyefinity . Two of them can use any connection or adapter, all others must be connected via DisplayPort or an active adapter (also called active mode or Eyefinity adapter ).

In principle, several standard graphics cards can also be operated in one PC, which means that more than two monitors can be operated on one computer without any problems. Basically, with all of these solutions, restrictions in relation to the 3D functions must be expected.

Multi-monitor programs are an alternative to connecting additional monitors to a computer. These enable the use of a notebook or tablet PC to expand the screen of the main PC.

Web links

Commons : Multi-monitor - collection of pictures, videos and audio files

ZoneScreen - software for using a second computer or PDA as a second screen (freeware)

ScreenRecycler - multi-monitor software uses VNC , runs on Mac (shareware)

DMX - a proxy X server , with which you can use several X servers in one display (open source)

Up to 6 monitors on one PC Instructions for Windows 7

Individual evidence

↑ Peter H. Ganten and Wulf Alex: Debian GNU / Linux basics, setup and operation. Version etch . 1st edition. Springer, Berlin Heidelberg 2007, ISBN 978-3-540-73338-6 , pp. 414 .
^ Jürgen Gulbins, Karl Obermayr and Snoopy: Linux: Concepts, Commands, Surfaces . 1st edition. Springer, Berlin Heidelberg 2003, ISBN 978-3-540-00815-6 , pp. 636 .

[1] Peter H. Ganten and Wulf Alex: Debian GNU / Linux basics, setup and operation. Version etch . 1st edition. Springer, Berlin Heidelberg 2007, ISBN 978-3-540-73338-6 , pp. 414 .

[2] Jürgen Gulbins, Karl Obermayr and Snoopy: Linux: Concepts, Commands, Surfaces . 1st edition. Springer, Berlin Heidelberg 2003, ISBN 978-3-540-00815-6 , pp. 636 .