Dear users of the SuperMUC Petaflop System, due to a scheduled block operation phase, SuperMUC will not be available for general batch processing between Tuesday, July 9, 8:00 and Thursday, July 11, 18:00. On Tuesday, approximately half the machine will be flushed, the other half will be flushed early on Wednesday. Flushed jobs for which the default rerun policy was specified, or for which restart is explicitly requested, will restart after the block operation phase is concluded. Login to the front end and submission of small jobs to the test queue will continue working during this period. The migration system supzero is not impacted by the interruption. The purpose of the block operation is focused work on scaling up selected simulation programs to the complete machine in the context of an Extreme Scaling Workshop; LRZ thanks IBM and Intel for providing specialist support for this opportunity. This information is also available on our web server http://www.lrz-muenchen.de/services/compute/supermuc/aktuell/ali4617/ Reinhold Bader