how to disable extended desktop in unix

hi guys,
i have a unix WS ultra45, I installed sol10 after that I found the screen is extended to second screen , any one knows how to disable that ?

If it is using an NVidia graphic card, use the NVidia server setting GUI (nvidia-settings) to disable it.

i can't find which card i am using ? how to check that ?

Sorry, I overlook you were using SPARC hardware. You probably have one of XVR-100 or XVR-2500. prtdiag should tell you.

Have a look at these XVR manuals that should explain how to disable xinerama:
Sun XVR-2500 Graphics Accelerator Installation and User's Guide - Sun Microsystems
Sun XVR-100 Graphics Accelerator Installation Guide - Sun Microsystems

thanks, it works from the manual

fbconfig -dev kfb0 -defaults