physical layer network standards Ethernet Go programming language physical layer network standards RS232 organizing operating systems in the Linux family physical layer network standards WiFi physical layer network standards RS485 inter-process communication methods multithreading programming principles local network construction principles developing user software for other Unix systems microservices architecture organization installation and configuration of operating systems setting up and checking networks object-oriented programming principles physical layer network standards SPI developing user software for Linux OS multitasking programming principles data structures OSI network model classic algorithms C++ with STL and standard no lower than 17 setting up and checking current hardware TCP/IP stack