When Initialization Is Performed

When Initialization Is Performed

The initialization entry points of ordinary (nonloadable) drivers are called during system startup, after interrupts have been enabled and before the message "The system is coming up" is displayed. In all cases, interrupts are enabled and basic kernel services are available at this time. However, other loadable or optional kernel modules might not have been initialized, depending on the sequence of statements in the files in /var/sysgen/system.

Whenever a driver is initialized, the entry points are called in the following sequence:

pfxinit() is called first.
pfxedtinit() is called once for each VECTOR statement in reverse order of the VECTOR statements.
pfxstart() is called last.

Initialization of Loadable Drivers

When a loadable driver (see "Loadable Drivers") is configured for autoregister, it is loaded with other drivers during system startup. (For more information on autoregister, see "Configuring a Loadable Driver".) Such a driver is initialized at system startup time along with the nonloadable drivers.

When a loadable driver is dynamically loaded at some time after system startup, its initialization entry points are called in sequence at the time it is loaded.