Typically an X input device is defined as a link from /dev/input to some other device special file, for example a serial port in the /dev/tty* series. The filename in /dev/input determines the name of the STREAMS module that is used to interface that device to the IDEV input system. For example, if the file is /dev/input/calcomp, the calcomp STREAMS module is loaded and pushed onto the stream from the device.
When a single STREAMS module is used to support two or more devices, you can use a hyphen-digit suffix on the filename. For example, the calcomp STREAMS module would be used for both /dev/input/calcomp-1 and /dev/input/calcomp-2.
When a device is initialized (as described in the next section), the STREAMS module is asked to return the X name of the input device. This name can be the same as the name of the device and the module, or it can be different. Typically the device and module names will reflect the hardware type (for example calcomp), while the X name reflects the kind of device (for example tablet).