Before American units head for Iraq, they go through a lot of training, especially practicing what they would do when encountering typical emergencies in combat. Headquarters units also practice, even though most of their time in Iraq is spent in front of computer keyboards and large, flat panel displays showing overhead and ground level video, as well as maps of operations and the status of supplies and equipment. One headquarters preparing to ship over and spend a year in Iraq is the 18th Airborne Corps headquarters, and its support units (1st Corps Support Command, 18th Airborne Corps Artillery, 44th Medical Command, 20th Engineer Brigade, 525th Military Intelligence Brigade, 18th Aviation Brigade, 18th Soldier Support Group and 35th Signal Brigade.) This headquarters will control all army combat and support units in Iraq. If anything big, and unexpected, happens, the corps headquarters crew is expected to respond quickly and accurately with orders to combat and non-combat units. Before shipping over to Iraq, the 18th Airborne Corps went through many training exercises, having what if? situations thrown at it to see how effective the reactions would be. These scenarios included things like; attacks against Kurdish politicians, the use of new weapons against coalition troops (like anti-tank missiles or home made napalm), a cholera (a highly contagious disease) outbreak in Sadr City and the killing of an important witness in the trial of Saddam Hussein.
Units like the 18th Airborne Corps headquarters would accumulate a lot of information about Iraq, stored in computer databases, before it left for Iraq, just so it could practice using all that stuff. It would also just take over a lot of computer equipment from the corps headquarters it was replacing, as would many of the units attached to the headquarters. The smooth the switchover process, an advance party from the 18th Airborne Corps headquarters would arrive in Iraq weeks before the rest of the troops did. The advance party people would start working with the outgoing troops, to make the transition as smooth as possible. The objective is to have the transition be unnoticed by the opposition.