This may be apocryphal. It was related to me by someone who worked for CSC. It seems at one of their facilities a few times a year some of the processing would stop. They were finally able to attribute it to public transportation and the angle of the sun. The story is when the sun was in the right position in the sky, and a bus arrived at a stop to pickup passengers at just the right time. A reflection off part of the bus would strike one of their tape drives and be interpreted as an end-of-tape marker. Ian A. MacGregor SLAC National Accelerator Laboratory -- //www.freelists.org/webpage/oracle-l