A new fast data logger and viewer at Diamond: the FA archiver

At Diamond Light Source, position data from 174 Electron Beam Position Monitors (BPMs) and a number of X-Ray BPMs is distributed over the Fast Acquisition communications network at an update rate of 10 kHz; the total aggregate data rate is around 15 MB/s. The data logger described here (the FA Archiver) captures this entire data stream to disk in real time, re-broadcasts selected subsets of the live stream on demand to interested clients, and allows rapid access to any part of the saved data. The archive is saved into a rolling buffer allowing retrieval of detailed beam position data from any time in the last four days. A simple socket-based interface to the FA Archiver allows easy access to both stored and live data from a variety of clients. Clients include a graphical viewer for visualizing the motion or spectrum of a single BPM in real time, a command line tool for retrieving any part of the stored data by time of day, and Matlab scripts for exploring the dataset, helped by the storage of decimated minimum, maximum, mean, and standard deviation data. (authors)