The Labs.Com X11 Lab MultiHead

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Multi-head (monitor) solutions

1. XFree86
2. VNC
3. X2X
4. Hardware Solution
5. Resources

XFree86 from version 4 on supports now multi-head, where multiple cards (PCI) can be addressed by a single X11-server. Also the Matrox G200 MMS (dual and quad monitor) are supported by Matrox for XFree86.

Xinerama

Xinerama makes X11 treat multiple monitors as one, e.g. one screen is splitted horizontally over three physical monitors. Xinerama HOW-TO How to setup XFree86 with multi-head and Xinerama

Some nifty hardware:

PanoramTech.Com PV290 DSK: 43.5"x11.5" (44" diagonal), 3x 1280x1024 = 3840x1024 total.

MassMultipless.Com Combining multiple LCD 2x, 3x, 4x.

MultiHead 2. VNC

VNC (Virtual Network Computing) provides to run the vncviewer with the option -shared that multiple machines access the same X11, WinXX, or MacOS desktop. In combination with X2X you can then connect multiple X11 (also running on several different machines) to one area of heads (screens) operated with one kb/mouse.

On server A:

% vncserver -geometry 1024x768 :1

... on machine B:

% vncviewer -shared A:1

and on machine C:

% vncviewer -shared A:1

MultiHead 3. X2X

X2X is a small program which allows to connect two X-servers (-form source-X11 with -to dest-X11) together:

colossus% x2x -from colossus:0.0 -to polaris:0.0 -west -resurface

colossus% x2x -from colossus:0.0 -to storm:0.0 -east -resurface

This way you can control from the keyboard & mouse of colossus (in my setup) two other screens on the left (west) and one on the right (east); under XFree86-3.3.x running two x2x caused problems, under XFree86-4.x this seems resolved and no problem anymore.

X2X (digital.com) Source-code

X2VNC X2X for VNC, homepage & sources

MultiHead 4. Hardware Solution

Electronic Switches

NTI: Video Matrix Switches n-machines with n-monitors

Mechanic Switches

We call this solution "monitor matrix" as it allows to easily find out required video-switches in a multiple monitor & multiple machine environment. An example you have 5 monitors, and one machine (deity) with dual-head, and three other machines. List each monitor horizontally and the machines vertically, which builds the matrix. Then mark with 'X' if a certain machine should be use a certain screen, like this: Monitors / Machine 22" 19" 19" 17" 15" LCD Extension Deity 1 X X 1:2 Deity 2 X 1:1 Elohim X X X 1:3 Profx X X X 1:3 Cerise X X X 3:1 Switch 1:1 4:1 3:1 2:1 2:1 Once you did so, count the 'X' vertically, and horizontally. The Extension means, one video-signal is extended to n-signals (1:n); the Switch is from n-signals back to one video-signal (n:1). When you have just 1:1 means it's a simple one-to-one cable, but otherwise you know how many video-extensions and video-switches you need. The video-networking of the above example would look like this: The Extensions can be a chained video-splitter, e.g. 1:2 is one Y-video-splitter, 1:3 are two Y-video-splitter in chain. The Switches are available as 2:1, 3:1 and 4:1, available in good computer stores. If you run e.g. 4x KVM-switch (Keyboard Video Mouse), then you can replace the one 4:1 Switch for the first 19" with your KVM-switch.

KVM

KVM-switch (Keyboard/Video/Mouse switch) usually used for multiple machines to one kb/mouse and monitor. There are 2x KVM upto 16x KVM, and even stackable upto 1024 machines. Often the video-bandwidth is limited, so pay attention for KVM what resolution at which refresh rate is supported, a few KVM switches provide 1600x1200 @85Hz easily. The main feature of KVM switch are their 'hot-key' switch ability, e.g. CRTL-ALT-SHIFT + 1, 2, 3 .. switches between the machines connected, the more expensive KVM's have OSD (on-screen display) selectors, which aren't as handy (I think) as hot-key switches. IOGear 4x KVM-switch is a good choice (aprx. $120 incl. cables). Other brands sell KVM at little higher price (e.g. an 4x KVM-switch) but often no cables are included and need to be purchased separately. For professional used KVM (e.g. 16x) check the interoperatability of your KVM extension-cables, so they can be reused also for other KVM-switches at a later time.

Related Infos

Monitors Monitor infos Keyboards Keyboards infos VideoCards Videocards infos InterOS Multiple OS'es in your network

MultiHead 5. Resources

RealTimeSoft.Com: Linux Multi-Monitor Some infos

                                                                                                                                   

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