Plattner is acutely aware of his problem, and he’s working on it. He has targeted a quartet of product areas that he hopes will spark growth: customer management, supply-chain management, e-marketplaces, and corporate portals, which allow employees of corporations to tap easily into internal data through the Web.

Besides, he’s happiest when he’s wrestling with a challenge. That spirit permeates his life—from the boardroom to his world-class racing yacht, Morning Glory. He’ll keep fighting even when the stakes are impossibly low. For instance, last year, during a break from the annual meeting of the company’s investment arm, SAP Ventures, Plattner arranged a race between teams of investors in rented yachts in San Diego harbor. At one point, with Plattner at the helm, his boat was on a collision course with another. "Hasso’s yelling at the other guy that we had the right of way. In the end, the other guy turned off. We missed by a few feet," recalls Gordon Hull, a venture capitalist at CMEA Ventures in San Francisco. "He’s got nerves of steel. I wouldn’t want to compete with him."

"Street fighter"

That out-there personality seems rooted in his childhood. Born in 1944 in Berlin, the battler in him emerged during adolescence. After his parents divorced, he was sent at age 15 to a strict, military-style boarding school in Bavaria. It was like moving from Manhattan to Texas overnight. "I had to become a street fighter," he recalls. "Once I pushed a big guy into a glass cabinet, and it shattered. I still have the scars," he says.

Other early influences shaped Plattner’s career. He worshiped John F Kennedy. "He had a vision," Plattner says. For a kid growing up in beaten-down Germany, Kennedy represented the promise of a new, can-do era. When Kennedy was shot, Plattner was devastated. Plattner followed in the footsteps of a grandfather and studied engineering—intent on being where the action was.

The future, it turned out, was to be built on electronics. In college, Plattner studied telecommunications, since a computer science program wasn’t available. Upon graduating, he got a job as a sales consultant for IBM in Mannheim, Germany. That didn’t last long. He left with four colleagues in 1972 to form SAP after IBM rebuffed them when they suggested creating a financial-software package for corporations. Their novel idea: to replace expensive custom applications with off-the-shelf packages. Since then, Plattner has been the company’s cheerleader and visionary, mapping out technology and strategy while the original chairman, Dietmar Hopp, managed the business. Plattner became the No 1 executive in 1998 when Hopp resigned and has remained SAP’s spark plug.

Sometimes, though, he has been the sludge that clogs up its engine. Even though customers complained for years about how difficult SAP’s products were to use, Plattner didn’t launch a campaign to fix that until 1998. He long refused to believe that marketing was important, and that cost SAP dearly in the competition with image-savvy Ellison. Plattner’s pride in SAP sometimes blossoms into full-blown arrogance. At a software industry conference in 1998, "Hasso shocked people by saying he didn’t believe SAP had to form alliances with anybody," recalls Mark Hoffman, CEO of Commerce One.

Plattner’s change of heart has been remarkable. In early 2000, even as he was forming SAPMarkets, an independent e-marketplace subsidiary in San Francisco, he accepted an invitation from Hoffman to talk about creating a partnership between SAPMarkets and Commerce One. Ultimately, over several months of talks, the two decided on an unusually close relationship in which they would co-engineer a new suite of integrated products. Plattner recalls that a high school art teacher taught him to be flexible. "He said: ‘When you reach the point that you don’t change your mind anymore, you know you’re old,’ " recalls Plattner. Now it’s one of Plattner’s mantras.

Plattner’s ongoing project is turning SAP’s engineering culture inside out. In spite of his efforts, the organization remains insular and slow to change its ways. His goal is to make sure SAP’s products are created with maximum input from customers—rather than in cloistered isolation by engineers at the labs in Walldorf, Germany. SAP’s engineering groups are now plugged into the sales organizations. SAP America, for instance, has lined up 100 customers to be "development partners" that actually help write code.

Corporate cookery

That kind of overhaul takes dogged persistence. Inside SAP, Plattner is like a chef—constantly stirring the pot. He spends about one-third of his work time in California, one-third on the road visiting customers and SAP offices, and the rest back at headquarters in Walldorf. At the home office, he often arrives with a new idea he wants to try out on his colleagues. The planned schedule usually gets thrown out, replaced by impromptu meetings in his fourth-floor office.

Since he vowed to change his ways, Plattner doesn’t try to do everyone else’s jobs. Co-CEO Henning Kagermann, for instance, runs sales and finance. That’s not to say that Plattner sits back passively and watches how others work. He has been the acting CEO of SAPMarkets since it was formed. And Plattner personally manages the relationship with Commerce One, making sure it doesn’t fall apart—which happens to most high-tech alliances. "He’s absolutely the change leader at SAP," says Jack Barr, a former top sales executive at SAP America who is now head of sales at e-commerce startup Atlas Commerce.

With a 10% stake in SAP worth $4.5 billion, Plattner has been richly rewarded. Now he’s giving some of his money away to help places with big problems—including $6 million to combat AIDS in South Africa and $55 million to the University of Potsdam in former East Germany. "I want to engage in battles and win them," he says. "You have goals. Now the goal is to pass Siebel."

At the rate Siebel Systems is growing, though, that will remain an unattainable goal for a long time. But given Plattner’s ferocious personality, it’s unlikely he’ll give up trying.

Steve Hamm with Stephen Baker in Paris—BusinessWeek