http://xorg.freedesktop.org/archive/X11R6.8.2/doc/Xvfb.1.html
http://www.moyo.biz/studio-moyo/install/xvfb/index.html
http://www.gfd-dennou.org/arch/dcl/dcl-tips/TEBIKI.dcl.virtual_dump.html
http://www.drk7.jp/MT/archives/001042.html