| bustype | Specified as GIO for GIO devices. The VECTOR statement can be used for other types of buses as well. |
| module | The base name of the device driver for this device, as used in the /var/sysgen/master.d database (see "Master Configuration Database" and "How Names Are Used in Configuration"). |
| adapter | Always 0, or omitted, for GIO, since there is never more than one GIO bus adapter in current systems. |
| ctlr | The "controller" number is simply an integer parameter that is passed to the device driver at boot time. It can be used, for example, to specify a logical unit number. |
| base | Device base address, as shown in Table 18-1. |
| probe or exprobe | Specify a hardware test that can be applied at boot time to find out if the device exists. |
You use the probe or exprobe parameter to program a test for the existence of the device at boot time. If the device does not respond (because it is offline or because it has been removed from the system), the lboot command will not invoke the device driver for this device. This facility is used in distributed /var/sysgen/system/irix.sm files in order to choose between the graphics board in slot gfx or in slot exp0.