Editing ATLAS experiment (section)

====Data generation====
Earlier particle detector read-out and event detection systems were based on parallel shared [[Bus (computing)|buses]] such as [[VMEbus]] or [[FASTBUS]]. Since such a bus architecture cannot keep up with the data requirements of the LHC detectors, all the ATLAS data acquisition systems rely on high-speed point-to-point links and switching networks. Even with advanced [[electronics]] for data reading and storage, the ATLAS detector generates too much raw data to read out or store everything: about 25 [[megabyte|MB]] per raw event, multiplied by 40 million [[beam crossing]]s per second (40 [[Hertz#SI multiples|MHz]]) in the center of the detector. This produces a total of 1 [[Byte#Multiple-byte units|petabyte]] of raw data per second. By avoiding to write empty segments of each event (zero suppression), which do not contain physical information, the average size of an event is reduced to 1.6 [[megabyte|MB]], for a total of 64 [[terabyte]] of data per second.<ref name=fact_sheets/><ref name=the_bible/><ref name="TPoveralldetector"/>