The Raspberry Pi as a Stratum-1 NTP Server

As an experiment, I purchased one of the low-cost credit-card-size Raspberry Pi computers, and have configured it to run NTP (Network Time Protocol). I have also used this board with a GPS receiver with pulse per second (PPS) output to make a stratum-1 NTP server, but as I know little of Linux, it has taken some time to achieve this aim! There are some helpful Linux commands scattered throughout this page. These notes are almost as much for my own records for the next time I need to visit this project, but I hope they may be helpful to others.”