Specifications

Console Autoconfiguration
When the console environment variable contains any value
other than s, the system autoconfigures the console terminal.
First the system searches all options for a crt driver. If a crt
driver is found, the system searches all option modules and
then the system module for a kbd driver. Because the system
module has a kbd driver, this search is always successful. When
the search for the kdb driver has completed successfully, the
crt and kbd drivers are loaded and the osconsole environment
variable is set to the slot numbers of the crt and kbd drivers,
respectively.
If a crt driver is not found, the tty driver is loaded from the
system module and the osconsole environment variable is set to
7, the slot number of the system module.
10–20 Using the Console Program