New York Stock Exchange clients demand hyperspeed execution. Bob Steinbugler of IBM Corporate Strategic Design details the reinvention of the tool that lets brokers manage 540 million shares a day.

"When the New York Stock Exchange engaged my team at IBM to design a next-generation wireless computer for floor traders, it was very specific about the handheld's technical requirements. But the Exchange gave us scant information on the user's actual needs. We couldn't get access to the traders because we'd disrupt their hectic work. This created a dilemma: how to design for a user we've never met?"

"When we saw the specs, we quickly realized that this was going to be a heavy, complicated device. It would have to be a wearable computer whose weight was distributed across the body to make it more comfortable. Traders are always on the move, and we wanted to keep the device close to their bodies so it wouldn't flap around."

"We wanted to balance the computer's weight of 2.7 pounds, so we designed a harness that strapped around the trader's upper torso. We used the trader's shoulders and torso to support the system's weight. The computer folded out, from the chest. We took the mock-up to the Exchange, after the market had closed, and recruited five traders to play with it. After an hour of testing, they hated the thing: It was too heavy and cumbersome to carry around for six hours a day. We told the Exchange that we needed to rethink our entire approach. We had to get the traders involved."

"By observing the traders, we saw that they used their handhelds intensely at the beginning and end of each day, and in short bursts in between. So we had to optimize the design both for when they used the device and when they didn't. They chose a 1.6-pound unit because it felt the lightest."

"Because the device needed to be hand-held for use and carried when not, we provided a shoulder strap. Our first mock-up fixed the strap to the e-Broker, but traders complained that the strap was rubbing grooves into their expensive suits as they moved the unit up and down."

"We developed a strap that uses a friction pad to grip the shoulder; an eyelet attachment lets the device slide easily along the strap. The strap itself is made of elastic bungee material to absorb shock as the traders drop the terminals into carrying mode."

"The eyelets swivel to let the traders carry the devices with the touch screens against their bodies, thereby protecting them. All of these ergonomic features came out of working with the traders. Their unmitigated feedback gave us the gift of clarity."

"Another challenge was to design the computer's backside. We gave the back cover a soft curve with no hard edges that might irritate the trader's hand, while still matching the different battery profiles we were considering. We built a strap that would wrap around one's hand, making it easier to grip the computer."

"So far, IBM has built more than 3,000 e-Broker terminals. These days, you can make technology do just about anything, but the e-Broker's design process taught us to look at technology holistically--to learn how people live with it even when they're not using it."