Computer operating systems based on the Linux kernel are used in embedded systems such as consumer electronics (eg. set-top boxes, smart TVs and personal video recorders (PVRs)), in-vehicle infotainment (IVI), networking equipment (such as routers, switches, wireless access points (WAPs) or wireless routers), machine control, industrial automation, navigation equipment, spacecraft flight software, and medical instruments in general.
Because of their versatility, operating systems based on the Linux kernel can be also found in mobile devices that are actually touchscreen-based embedded devices, such as smartphones and tablets, together with personal digital assistants (PDAs) and portable media players that also include a touchscreen. This is a challenge for most learners because their computer experience is mainly based on GUI (Graphical user interface) based interaction with the machine and high-level programming on the one hand and low-level programming of small microcontrollers (MCU) on the other hand while the concept of command line interfaces is widely unknown.[1]