"There is always a risk running new code," said Jim Vincent, a systems engineer at Nationwide Mutual Insurance Co. in Columbus, Ohio. But he believes the trade-off is more than worth it. "There is a possibility that something our users require may not work the same, or work incorrectly," he said.

Vincent said Nationwide received the virtualization software in July 2005 and within days had it loaded and running. It was put into production last December.

The z/VM 5.2 improves its 64-bit bit performance and memory management, said Vincent. And by jumping on it quickly, his company was able to upgrade before other users. "There's a little business advantage," he said.

A second plus is having direct contact with IBM developers and key people working on the software, said Vincent. That gives him, and other beta testers, the ability to influence future product development.

There are also some altruistic reasons for getting involved, said Vincent. Occasionally someone from the Share user group will find out about his work and tell him, "Thanks, you fixed it before we had to," he said.