Dynamic Definition of Device Special Files

Dynamic Definition of Device Special Files

In a more sophisticated installation you might want to have the device special files created, or recreated, dynamically each time the system boots. This is the purpose of /dev/MAKEDEV (see "The Script MAKEDEV"); it removes and redefines device special files based on information in the hardware inventory.

Much of the logic in /dev/MAKEDEV depends on information reported by the hinv command. Through IRIX 6.2, there is no OEM interface for drivers to the hardware inventory (see "Hardware Inventory"), so at this time there is no opportunity for your driver to pass information through the inventory to /dev/MAKEDEV.

However, there are other possibilities. For example, if your driver supports a control unit with an unknown number of minor devices, you could statically create a single device special file to represent the control unit. You could write the driver so that an ioctl() function directed to this file returns the count of actual minor devices.