Device File Names

If you are using OpenWindows(TM) software on multiple monitors, you should be familiar with the way frame buffer devices are assigned to UNIX device file names. Multiple frame buffers used with OpenWindows software require that you supply UNIX device file names for frame buffers on the command line when either is started.

The UNIX boot messages identify the frame buffer as /dev/fb (where fb is the type of frame buffer). The /dev/fb usually has another device file name such as /dev/fbs/cgsix0, /dev/fbs/bwtwo0, or /dev/fbs/leo0, depending on the type of frame buffer. When a second frame buffer is added, the system decides which is /dev/fb based on the SBus slot number of each frame buffer and the sbus-probe-list EEPROM variable. The /dev/fb is the frame buffer in the first SBus slot defined in the sbus-probe-list.

If a TurboGXplus card is added to the system with an existing GX frame buffer, the sbus-probe-list also determines which is /dev/fbs/cgsix0 and which is /dev/fbs/cgsix1.

For example, assume that the sbus-probe-list on a SPARCstation 10 system has the default value of f0123 and that SBus slots 2 and 3 contain TurboGXplus cards. The TurboGXplus card in slot 2 will be known as /dev/fb and /dev/fbs/cgsix0; the TurboGXplus card in slot 3 will be known as /dev/fbs/cgsix1.

The command line examples shown in this chapter use possible device file names to refer to frame buffers. Substitute the device file name that is appropriate for your system.