Uncle Sam is calling on IBM to help prevent enemy missiles from ever reaching US soil. IBM plans to announce on Monday that it has won a deal to supply the Defense Department with 66 high-end p690 "Regatta" Unix servers to be used as part of the country's ground-based missile defense program. About 20 of the servers will go to Boeing, which is managing the testing and simulation part of the missile defense program, while the remainder will be used by TRW, which is handling the command and control part. Instrumental to the deal was certifying that AIX, IBM's version of Unix, complied with a Defense Department program that puts a common user interface across many different types of Unix-based systems. The effort to move to a so-called Common Operating Environment, which began in the mid-1990s, is aimed at saving millions of dollars in training costs. IBM said it had already decided last year to do the work necessary to qualify AIX for the common interface, said Greg Lefelar, federal manager for IBM's eServer unit. Because of the amount of testing and documentation involved, it cost IBM more than $1.5 million and took more than a year to get qualified, but having done so could mean even more business down the road, Lefelar said. "It opens up our ability to compete in a number of programs within the Department of Defense," he said. When the common interface program began, the Defense Department ported the common interface to the most prevalent Unix flavors of the time--HP's HP-UX and Sun's Solaris. With some urging from IBM, they added Big Blue's AIX, but dropped support about a year later. "They simply felt the demand did not justify the increased workload," Lefelar said. That meant that for a number of years IBM was basically shut out of many military contracts. At the same time, IBM did not always have the most competitive Unix systems on the market, Lefelar said. With Regatta, IBM has the strongest Unix product lineup in its history, Lefelar said. IBM introduced the 32-processor Regatta server last October. Sun Microsystems is the top seller of Unix servers, with Hewlett-Packard in second place and IBM in third. However, IBM has gained share since it began a concerted effort in 1998 to reclaim Unix sales. In May, IBM announced a deal to sell dozens of Unix servers, including some Regatta machines, to run Colgate-Palmolive's core global business software. The same month, the company inked a deal with the National Oceanic and Atmospheric Administration (NOAA) worth up to $224 million to supply clustered Regatta servers to produce forecasts for the National Weather Service. News.com's Stephen Shankland contributed to this report.