Competing with Microsoft was tough, given its ability to cut deals with customers, says Mitchell Kertzman, a senior executive with Sybase from 1995 to 1998 and now CEO of Liberate Technologies, a WAN software provider. "It was typical Microsoft--all-out, up-against-the-wall marketing and selling," Kertzman says.

Along the way, SQL Server grew from a departmental system to a legitimate platform for demanding workloads. "In previous times, I would have said they didn't have the heavy lifting we needed," says tech-exec veteran Sateesh Lele, the new VP of IT and CIO of Build-To-Order Inc., a startup that's evaluating database products, including SQL Server, to support its plan to sell customized automobiles to consumers. "The fact that I'm considering it indicates they've come a long way."

Still, Oracle and IBM, the top two players in the database market respectively, each had more than double Microsoft's market share last year, portending a long climb ahead. While Microsoft surpassed Oracle last year as the leading provider of relational databases on Windows, according to Gartner, Microsoft's share of the worldwide relational database crept up just two percentage points. And SQL Server's close attachment to Windows may hurt it in the long run, says Robert Shimp, VP of marketing for Oracle's 9i database. "Microsoft has boxed themselves in because SQL Server doesn't run on Linux," Shimp says. "We expect Linux to surpass Windows as the dominant server platform in a few years."

Yet, while Linux has been nipping at the heels of Windows for years, it's not at all clear that the open-source operating system will have the kind of broad acceptance Windows enjoys. Linux, mostly used in niche environments, is working from the outer edges of the business market into the middle. But Microsoft is strong in the middle and moving upstream. Much of Microsoft's research and development is going into supporting the growing number of super-size databases.

"We're starting to bump up against companies [that] have the most of everything--the most customers, the most products," says Bill Baker, general manager of business intelligence for SQL Server. "The next big step is to have not just the transactions, but the pre-transactions, such as data on advertising efforts. When you start to bring all those pre-transactions in, you can ratchet up data warehouse sizes. We're on the verge of one of these generational jumps."

IBM, NCR's Teradata division, and Oracle already are adept at handling what are known as very large databases. For Gray and other database designers at Microsoft, it's been a years-long effort to catch up. SQL Server is capable of supporting tens of terabytes of data, Gray says, pointing to industry benchmarks and an ambitious project to map outer space, called the Sloan Digital Sky Survey (skyserver.sdss.org), to prove it. The project accumulates 200 Gbytes a week, or 9 terabytes a year, on SQL Server, one of several databases used in the project.