Operating system is something that IT people must master skillfully. There are many kinds of operating systems, including traditional PC operating systems, such as Windows series, Linux series and MacOS series, as well as mobile phone Android system, iOS system and WP system, as well as various embedded systems (EOS), such as RTX, WindowsCE and embedded Linux (Raspberry Pie).

Computer network knowledge is essential basic knowledge for IT personnel, including network architecture (OSI model), functions of network devices, design of network topology, configuration of computer routers, etc.

Engineers engaged in operation and maintenance positions have higher requirements for network knowledge, and usually operation and maintenance personnel need to be trained by professional manufacturers before they can take up their posts (with certificates). Like Huawei and Cisco, they all have corresponding engineer certification systems.