A long, sad night stretched into a long, sad morning in the U.S. Army's 101st Airborne Division headquarters tent today. The day and night shifts had been intermingled since before 2 a.m. when word first arrived that a grenade-throwing soldier at nearby Camp Pennsylvania had run amok, killing one officer and wounding 15 other troops of the 1st Brigade.

At 7:40 a.m. the division chief of staff, Col. Thomas J. Schoenbeck, turned to face the three dozen officers sitting at three rows of tables, their opened laptops sheathed in plastic against the dust. The morning battle update briefing, known as the BUB, was about to begin.

"We're going to do this quickly," said Schoenbeck, a tall, immensely calm infantryman who recently commanded the 1st Brigade. "Be very concise and give the CG [commanding general] only what he needs to know to make decisions."

Thirty seconds later, Maj. Gen. David H. Petraeus stepped through the flap that serves as a door. He was somber but alert, despite little sleep. Among other events during the eventful night, a Patriot missile from a launcher parked outside the camp had roared over the headquarters to destroy what was described as an incoming missile.

Petraeus removed his helmet and eased into a gray folding chair at the head table. Schoenbeck and the division operations officer, Lt. Col. Rick Gibbs sat on his left; the division intelligence chief, Lt. Col. D.J. Reyes, on his right. "Okay," Petraeus said, "let's go. D plus four."

If the four days of the Iraqi war have begun to blur together, this morning will remain vivid for the 101st. The division's first casualties allegedly have been inflicted by one of their own, an affront that many soldiers -- steeped in the lore of Screaming Eagle valor at Normandy and Bastogne -- find hard to grasp. An engineer now in custody, identified as Sgt. Asan Akbar, 31, is suspected of throwing three grenades and firing at least two shots in the fragging; his motives were uncertain. The 1st Brigade commander, Col. Ben Hodges, escaped with minor shrapnel wounds, but several staff officers were more seriously hurt and have been evacuated to Germany. Capt. Christopher Scott Siefert, 27, from Fort Campbell, Ky., was killed. Replacements had to be found and morale rejuvenated.

Petraeus studied four large screens and an enormous map at the front of the room. Despite the calamity at 1st Brigade, his preeminent task was to focus on battles to come. One by one, staff officers offered quick status reports with computer graphics. "Okay," Petraeus said. "Got it. Got it. Okay." A master sergeant previewed the weather; a storm is coming later this week. "Got it."

One screen depicted several streams of blue icons across a map. Known as Blue Force Tracker, the new system uses satellite-based transmitters in selected vehicles and aircraft to allow commanders to follow the battlefield trace with far greater fidelity than ever before. The 3rd Infantry Division could be seen bulling 200 miles up the Euphrates Valley.

Another blue thread showed the 3rd Brigade Combat Team (BCT) of the 101st, the division's first major unit into Iraq. Once refueling bases are established, the rest of the 16,000 Screaming Eagles can join the fight, including 72 AH-64 Apache attack helicopters. "Part of this," one officer said, "is to make the Iraqis sweat, to wonder where the 101st is with all those Apaches they've seen pictures of."

Helmets, gas masks and rifles lay in heaps around the tent. The room was jammed; officers shuffled sideways through the aisles with murmured "excuse mes," trying not to trip over the snarled computer cables. Placards on each laptop identified representatives from throughout the division: surgeon, lawyer, military police, engineers, air defense, various liaison officers.

A green field phone chirped in front of the commanding general. Petraeus listened for a minute, then turned in his chair and announced into a cordless microphone that the Army staff in Washington would "provide the personnel to backfill those we lost last night in the 3 BCT. Pretty good indicator of our Army's support for us."

On the tent's cathedral ceiling, a black-and-white television image from an aerial drone flickered like a silent movie. More staff officers ticked through the status of their units. "Okay. Okay. Got it. Next." A bleary-eyed major sidled to the stainless steel percolator and drew a mug full of coffee. Others sucked on tubes from their backpack water sacks. Someone blew dust from a keyboard with a sharp hiss from a can of compressed air.

Petraeus surveyed a list of impending division actions. "This goes this afternoon. This should go this afternoon. Tomorrow. Tomorrow night." A six-foot timeline, labeled "graphic execution sketch," plotted the division's past, current and future operations over a two-week period. A poster above one screen listed six questions, none of them rhetorical: "What are we doing? What is the enemy doing? Where are we vulnerable? Where is the enemy vulnerable? How is our plan doing? What changes do we need to make to that plan?"

Schoenbeck stood, spectacles pushed up on his head, and raced through the end of the agenda. The briefing was over. Crimson numerals on a digital clock showed that the conference had lasted barely half an hour.

Petraeus rose and faced his staff. "To lose a Screaming Eagle is a terrible thing," he said, his voice steady. "The way we lost one last night is a real tragedy. The best way we can honor those who were hurt last night is by driving on and accomplishing the mission. Air assault!"

"Air assault!" the officers answered in unison, then got on with their day.