One of my projects is a Linux-based embedded device for playing commercials. The software part is a Python application controlling an MPlayer process in slave mode.
To make the whole system more fault-tolerant I wanted to use watchdog timer which would reboot the machine in case of software failure. Thus I needed to talk to Linux watchdog driver from my Python application. The Linux watchdog API defines a number of ioctl commands which can be sent to the driver. So, I wrote an extension module which enables Python programms to use Linux watchdog API.