The catalog, available on Optaros' Web site, rates software on a scale of 1 to 5 on factors such as functionality, the vibrancy of the developer community behind it, the software's maturity and stability, and its projected trajectory. Those factors are then used to calculate the software's readiness for use by midsize and large corporations.

The minireviews were based on the experiences of nearly 100 consultants, many of whom had directly installed or maintained the software for clients. The reviews all involve products released by last fall and include only the best of the nearly 140,000 open-source software projects available, according to the catalog's primary author, Bruno von Rotz.

"Every tool that made its way into our catalog is already pretty good, even if we gave it only a 1 or 2 [out of 3] for its enterprise readiness," he said.

Some of the rankings for well-known open-source software were surprising. The Berkeley DB XML database garnered only an enterprise readiness rating of 1. Oracle Corp., which acquired the database last year, did not reply to a request for comment by press time.

Hot groupware product Zimbra also got a 1 for enterprise readiness (products rated zero are not included in the guide). According to a spokeswoman for San Mateo, Calif.-based Zimbra Inc., the review was for the 3.0 version of its collaboration software. "Optaros has been so impressed by the improvements in Zimbra Collaboration Suite 4.0 that they are deploying it for internal use, and they are now a customer," she said.