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su tomcat  c "/usr/X11R6/bin/Xvfb :1  screen 0 800x600x24 "&

Once you have launched the virtual frame buffer server, you can test that it is running. You will probably run this as

root.

[root]# su tomcat

bash$ mathematica  display :1

Of course, one problem with confirming that the front end is running correctly with this server is that you cannot see

it on  the  screen!  This makes  it  hard to  see  a  dialog box indicating  an  error. One  way  to  see  what the  front  end  is

displaying is to inspect a dump of the server with xwd and xwud, which you can do with the following.

xwd   display :1  root | xwud

This will show what the front end is displaying. For example, if you see a message about not finding the password,

you may need to add a pwfile command line option.

When you are running the  virtual frame buffer  X server, you will need to modify your  MSP.conf file to instruct

the  front  end  to  use  this  server.  The  setting  of  FrontEndLaunchCommand  is  described  in  the  section  on  site

configuration in the Appendix. Here is a sample setting.

FrontEndLaunchCommand=mathematica  mathlink  display :1  nogui 

 geometry 1000x500+10+10

On some systems, such as Sun/Solaris, the X server has problems when being launched by the user tomcat since

the  permissions  to  the  /tmp/.X11  directories  have  been  restricted  for  security  reasons.  The  problem  manifests

itself with a message  that says the system cannot establish any listening  sockets. One  solution would be to modify

the directories so that tomcat can write to them. For more detail see http://www.faqs.org/faqs/Solaris2/FAQ/.

Manual Font Installation

The front end cannot run without access to the Mathematica fonts. If you notice from the output of the X server with

vncviewer  or  xwd  that the  front end  is  displaying  a  dialog box indicating  that it cannot  find  its fonts,  you  will

have to take some further steps to locate the fonts. One solution that is simple but drastic is to copy the Mathematica

fonts into your X distribution.

cd /usr/X11R6/lib/X11/fonts

cp  r 75dpi 75dpi.orig

cd 75dpi

cp /usr/local/Wolfram/Mathematica/4.2/SystemFiles/Fonts/X/*.bdf  .

mkfontdir

This is really a poor solution to be avoided if possible. One deficiency is that if you update your copy of Mathemat 

ica, you will have to remember to copy the new fonts. The proper solution is to launch Xvfb so it either uses a font

server  or  a  font  path  setting,  as  described  above.  Remember  that  this  is  not  a  problem  when  working  under  Win 

dows. 

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