Fig. 1From: Data systems for the Linac coherent light sourceLCLS data flow. The top half of the figure represents the Online system which includes the DAQ and the Fast Feedback Layer. There is one Online system instance per instrument. The bottom half of the figure shows the Offline system which is shared across LCLS instruments. When the DAQ begins a new run for recording, the data management system ensures that the new files are registered in the file catalog and launches an automated process to immediately begin the transfer of data from the data cache nodes to the fast feedback (FFB) nodes as the raw data are being writtenBack to article page