Steve Jobs didn't disappoint Macintosh fans on the opening day of Apple Expo in Paris Wednesday. The Apple leader delivered the public beta version of the long-awaited operating system upgrade OS X, as well as two new iBook laptops. But even Jobs, known for his ability to pull off the odd miracle, couldn't erase all lingering traces of doubt from the minds of Mac users still waiting to find out how the upgrade process will affect their machines. As promised, Apple made available the public beta of OS X, the successor to OS 9 based on a combination of NeXT's NextStep and Free BSD Unix. Besides promising greater stability, OS X radically alters the user interface, throwing out such 16-year-old mainstays as the Apple Menu and the Window-Shades system of collapsing windows. As previously reported by ZDNet, OS X will run legacy applications in emulation, but to take advantage of OS X features such as memory protection, users will have to buy specially-ported software. Thousands of business users attending the show's opening day -- not open to the public -- were generally optimistic about the new OS. An Apple employee said the company had distributed at least 700 copies of the beta (for a fee of £29.95 to cover printing) in the three hours or so after Jobs' keynote speech. With a queue stretching to the end of the massive exhibition hall, he said he expected to sell "many more" by the end of the day. "We've been waiting for this so long, another 45 minutes [in the queue] won't make any difference," said one graphic designer waiting for his copy. Despite the much-hyped technical features of OS X, Jobs appears to be pulling an iMac with the new software, stressing its ease-of-use and general coolness as much as its Unix origins. The message was not lost on users. "I just think it looks cool, I want to play with it," said another user in the OS X queue. Others had lingering doubts about what the upgrade would mean for their wallet. "I'm a graphic designer, and I have thousands of dollars invested in software for my system," said a US-based user. "I just wonder how much it's going to cost me to get it all working with OS X." Most major Mac software manufacturers, including Adobe, Macromedia and Microsoft, have committed to porting their applications to OS X for the system's official launch in early 2001, but pricing for upgrades has not yet been announced. Those applications that are not ported -- and shareware or applications from smaller companies might take some time -- will have to run on the OS 9 emulator. This isn't ideal for many applications, according to several beta testers, as they will take a significant performance hit. "It isn't snappy," a Canadian beta-tester confirmed of the emulator. The show appeared to get off to a flying start, packing the exhibition hall, though only 15 percent were estimated to be from outside France. Apple's biggest European show to date could have been any major Mac show except for a few telling details, such as the Minitel terminals here and there amidst the iMacs and G4 Cubes. Visitors seemed impressed with innovations such as the iMac's movie-editing capabilities and the 20-centimeter-square G4 Cube workstation. "Ah, t'est mignon, toi," one visitor crooned over the Cube ("Oh, you're cute, you."). What do you think? Tell the Mailroom. And read what others have said. Take me to the Apple expo roundup