This is a great topic for me. Network interface built in a computer or added on as expansion as into the slots, are the physical parts to handle. But say in Wi-Fi network, each file contributing to the network must run at impressive accuracy for the whole network to run. There are many examples already given about File IO and anyone can use it and compile it and store it on their own and the other parties system. I am reading a book by Jackie Barker, phd in computer science, Beginning Java Objects. Excellent way to read is using UML, and to figure out where things are.