While Microsoft continues to trumpet the success of its NT operating system over Unix-based systems, the US Navy is having second thoughts about putting NT at the helm. A system failure on the USS Yorktown last September temporarily paralyzed the cruiser, leaving it stalled in port for the remainder of a weekend.

"For about two-and-a-half hours, the ship was what we call 'dead in the water,'" said Commander John Singley of the Atlantic Fleet Surface Force.

The warship was testing its new Smart Ship system, which uses off-the-shelf PCs to automate tasks that sailors have traditionally done themselves. "The Navy started the Smart Ship program with three essential goals in mind: improve combat readiness, reduce crew workload and operating costs, and to do it safely," said Singley.

The Smart Ship program is still in development, and officials said glitches are to be expected, but in this case the problem appeared to be more political than technical. Using Microsoft's Windows NT operating system in such a critical environment, some engineers said, was a bad move.

"The simple root of the problem on Yorktown was that politics were played in the assigning of the contract – there was not a discussion of engineers, it was just a very small group of people pitching for it," said an engineer close to the project, who spoke on the condition of anonymity.

In a statement issued this week on why NT was chosen over Unix, the Navy said that while Windows NT was specified in the Statement of Work as the operating system for the workstations in question, other components of a coming upgrade will primarily utilize Unix-based systems.

"They rushed this stuff on the ship, there was no real prototype, and then they tried to make things work as they went along," the source said. "I don't think that Unix or NT were ever really evaluated – it was just somebody thinking this was good, with no knowledge."

The statement said that Unix is still being considered for future Smart Ship technologies, acknowledging that many systems already utilize Unix-based systems and that a "government team is currently researching the best technical and financial solution[s] ... of which the decision to use Windows NT or Unix will play a major role."

The source of the problem on the Yorktown was that bad data was fed into an application running on one of the 16 computers on the LAN. The data contained a zero where it shouldn't have, and when the software attempted to divide by zero, a buffer overrun occurred – crashing the entire network and causing the ship to lose control of its propulsion system.

Singley said that human factors were considered in the decision to use NT, partly because it was thought to have a more friendly graphical user interface (GUI) than Unix systems. Critics of the move pointed out that modern Unix-like operating systems have multiple GUIs to choose from.

Some additional factors may have influenced the decision to go with NT as well. In the Navy's "Information Technology for the 21st Century" (IT-21) report, NT 4.0 is named the operating system standard. In addition, some commercial, off-the-shelf products were used, which tend to come pre-installed with Microsoft products. Furthermore, Microsoft's Bill Gates nominated the Smart Ship program for the ComputerWorld/Smithsonian Awards Program.

But there has been growing public scrutiny over the use of Windows NT in critical enterprise environments.

"Why Windows NT Server 4.0 continues to exist in the enterprise would be a topic appropriate for an investigative report in the field of psychology or marketing, not an article on information technology," said John Kirch, a networking consultant and Microsoft certified professional, in his white paper, Microsoft Windows NT Server 4.0 versus Unix. "Technically, Windows NT Server 4.0 is no match for any Unix operating system."

The paper goes on to say that, when reliability is of utmost importance, Unix-like systems are preferable. That includes the free, open-source Linux operating system, which was recently shown to be the only non-Microsoft operating system whose user base is steadily growing. Vendors including Oracle, Informix, and Computer Associates have recently announced plans to support Linux.

The Navy has let a contract for four more Smart Ships, with the possibility of adding another 22 to the fleet.