Can someone tell me when the /proc/dahdi files are created for spans? Are they created when asterisk starts (or the asterisk init script) – if not what script creates them?
That file structure is created by dahdi and the associated board driver after they are modprobed into the kernel.
/proc/dahdi is created when dahdi is loaded. Each span N that is loaded creates /proc/dahdi/N .
See the README:
http://docs.tzafrir.org.il/dahdi-linux/#_procfs_interface_proc_dahdi and while we’re at it: the following sections about the sysfs interface.
/proc and /sys are generated by the kernel. No script generates them. A
script may trigger the load of those modules. Those modules will be loaded typically in the dahdi init script, if not loaded earlier by hotplug (if the DAHDI hardware driver is not blacklisted).