a. The UU server ran on Linux, MOUL used Win2k3. Why did they switch to a proprietary O/S? If they needed something that W2k3 had but Linux didn't, well, that makes back-porting to Linux tougher. b. If they went to W2k3 for server-specific APIs (see (a)), then it might not run out-of-the-box on XP, ...