by , 1:05 PM EDT, October 31st, 2007

In what seems to be a notable about-face, Apple has changed its Mac OS X Leopard Server license agreement to allow multiple, virtualized copies of Mac OS X to run on Apple hardware, according to Adam Engst at Tidbits on Wednesday.

Heretofore, only one copy of Mac OS X Server could run in a single Apple labeled computer. Many IT managers in the industry have moved to multiple instances of OSes running on a single server for various cost and technical reasons. Some felt that Apple's prior stance was hurting the company, and now, Apple has changed its license agreement to be more flexible, according to a systems engineer at the University of Wisconsin-Madison, Dave Shroeder, who read the new license carefully.

The change, which applies only to Leopard Server, allows multiple instances of the OS to run on Apple hardware (typically an Xserve) so long as they are each properly licensed and paid for.

"Enabling Leopard Server to run in a virtual machine may take some time, but we're working closely with Apple on it and will make it public as quickly as possible," Ben Rudolph, Director of Corporate Communications for Parallels told Mr. Engst. [Mr. Rudolph also wrote about this license change and Parallels' efforts in his Blog Wednesday: "When will you see it? In the next several months," he wrote.]

Whether this will allow IT managers to obtain real gains is an interesting question. In the case of Windows, separating services with virtualization is a great security measure, according to John Welch, a noted Macintosh author and IT administrator. With UNIX systems, it's not so critical to isolate those services. Even so, Mr. Rudolph added "We're hearing from our customers ... that the 'holy grail' of Xserves is to run multiple, isolated, near-native instances of Mac OS X Server on the same box, at the same time. If you couple that with the ability to run Windows and Linux next to those instances of Mac OS X, you've just made Xserves even more compelling for enterprises large and small, even non-traditional Apple shops."

That's the key -- giving IT managers the flexibility they've longed for. In the end, it will likely sell more Xserves, and Apple has nothing to lose from this minor but welcome adjustment to the Leopard Server license.