"We knew what we were looking for, and Microsoft had it," Schroer said. "Our whole strategy is fairly well-aligned with Microsoft, so we thought we might as well use their license, too."

And despite the traditional conservatism of its large manufacturing customers, Aras has been getting new code back. Currently, there are 30 projects listed on the company's open-source community site, which is hosted by Microsoft. Major code contributors include Motorola, the US Army, Rolls-Royce, Delphi, Ingersoll-Rand and Lockheed-Martin. All of their code has been incorporated into Version 9 of Aras' Innovator software.

And while Aras might be an open-source heretic in some ways, it's a total convert in others.

For example, the company vows to maintain a Red Hat-like model of making all of its technology features available free of charge, and to not switch to a two-tier model that would let it charge for access to some features and their source code. Some other vendors are looking at the latter approach, most notably Sun Microsystems with the MySQL database, although Sun this week backed off an initial plan to charge for some upcoming data backup features.

The stand taken by Aras is a brave one, said Charles King, an analyst at Pund-It. "Giving it away for free and hoping to make it up with services is a notoriously difficult way to succeed," said King, who was more bullish about the decision by Aras to remain Windows-only. "You go where the business is, and there are a lot more business opportunities for Windows than Linux," he noted.

Schroer said he has offered advice about going open source to other small, closed-source vendors, although none of them have made the leap thus far. But he thinks that all software vendors -- even the large ones that depend heavily on license revenues -- will have to make the switch eventually.

"Pick a date in the future, but all software vendors will be using this model at some point," Schroer said. "When you are literally spending as much money on selling as the license revenue [you bring in], it becomes a hostile way of selling. And it's not a healthy relationship anymore."