In addition to its other challenges, the military is working in the midst of a years-long mandate to streamline and modernize the Defense Department's stovepiped computer systems, some of which are custom-coded and decades old-yet still important to getting troops and supplies home. Some of this work began in 2003 because of problems getting equipment and supplies into Iraq after the war started. Repair parts and other material piled up because they were inefficiently packed and had to be manually sorted once they arrived. Troops kept reordering because the computers couldn't tell them where the stuff was. The Government Accountability Office, which conducts investigations for Congress, found a $1.2 billion discrepancy between material shipped to the Army and material received by the troops.