Modules

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it would be likely to do so under some level of system load because of the

additional time needed to load the modules from disk.

The other point has to do with special hardware configuration. If there is a

modem that uses a nonstandard interrupt for the given slot location, the sys 

tem will install the driver and configure it properly using setserial. However,

if the driver isn't used for several minutes, it will be unloaded. When the

driver is next needed, kerneld will load it, but knows nothing of the special

configuration needs of the driver. This results in the driver trying to use the

wrong interrupt for that device, and failing. The resulting symptom is that

if the system establishes a PPP connection within the first several minutes of

operation, the connection will be made in the standard fashion and work as

expected. If, however, the system is allowed to sit quietly for several minutes

after reboot, the PPP connection will never get established. The chat program

(if that is how the connection is established) will time out waiting for the first

response from the modem because it isn't servicing the proper interrupt. This

can be fixed temporarily by issuing another call to setserial with the proper

interrupt value for the card. The better fix is to explicitly name the device

driver in /etc/modules. Adding serial to the list of modules in /etc/modules

will cause the module to be loaded by init and, later in the boot process,

configured with setserial. It will also have the beneficial side effect of causing

kerneld to leave the module alone and never unload it. Thus, the configuration

initially provided for this driver remains unaffected and the device continues

to work properly.