That's the question Apple will begin to address Monday at its weeklong Worldwide Developer Conference in San Jose, California. By choosing to build Mac OS X on Unix, the company opens up thousands of new applications to Mac owners -- potentially expanding Apple's market share -- and gives Unix developers access to a lucrative new audience. Unix developers' interest in Mac OS X is simple: It is the first desktop Unix-based operating system to reach the mass market. Early signs show that Apple is off to a good start in wooing Unix developers despite the loss and replacement of its head of developer relations earlier this year. Still, developers and industry analysts warn that Apple has a long way to go before it understands the Unix community or delivers to them the tools needed to effectively bring their programs to the Mac. Mac OS X, the first major overhaul of Apple's operating system since its 1984 introduction, is based on BSD Unix, a popular variant of Unix. Apple in late March released Mac OS X at retail, and on Monday said the OS would ship on all new Macs. Apple has gone down the Unix road before. In the early 1990s, the company sold A/UX, a version of Unix System V, designed to run on Apple's Macs and servers as an alternative to the Mac OS. But A/UX didn't easily run existing Mac applications and attracted few buyers. The company later discontinued it. Any significant change in operating systems is risky, particularly for a niche market company like Apple, Guernsey Research analyst Chris LeTocq said. "No matter how great an operating system is, you still have to have applications to run on it," he said. For one, Apple must convince its existing cadre of developers to move established applications over to Mac OS X. Apple has had limited success with that so far, LeTocq said. Although Macromedia this month released FreeHand 10 and Bare Bones Software BBEdit 6.1 for Mac OS X, some of Apple's largest partners, such as Adobe Systems and Microsoft, are six months or more away from releasing some of the most popular applications for the Mac. Other programs are coming out, but the majority from smaller developers. At the same time, Apple is trying to woo Unix developers to Mac OS X, which would open up thousands of new programs to the Macintosh operating system. To facilitate Unix developer relations, Apple has entered a partnership with the O'Reilly Network. The Web site, managed by book publisher and Web portal pioneer O'Reilly & Associates, is a popular destination of open-source software developers. "Right now, there's definitely curiosity about Mac OS X" from Unix developers, said Derrick Story, managing editor for O'Reilly Network. "What they find when they begin poking around inside (Mac OS X) will have a lot to do with whether that interest is sustained or remains a curiosity. It's hard to say right now how that's going to go." Still, Story sees promising early signs -- and not only from Unix developers. The larger, established Mac development community is also seeing a new side of Apple. "The biggest gripe of Mac OS developers in the past was you couldn't get inside it," Story said. "The tools just weren't there. Now, they are." Keeping both sets of developers happy will be a challenge -- and it is something Apple is taking seriously, said Phil Schiller, Apple's vice president of worldwide marketing. "We're not getting ahead of ourselves with Mac OS X," he said. "We know there is a lot of work in front of us, and probably the biggest thing and a major milestone is the developer conference." One of the first developers to get behind Mac OS X was Alias|Wavefront, the SGI subsidiary and maker of 3D animation and design program Maya. Richard Kerris, director of Maya technologies, said the company made the decision more than a year ago to move Unix-based Maya to Mac OS X. "If you talk to the artists, they're usually brought up Macs," he said. "There's a huge community of artists that use the familiar Mac tools that haven't had the high-end capabilities and have had to push the envelope of what can be done. Now, hopefully, we're going to see higher-end apps like ours coming to the Mac." Frank Gillett, senior analyst with Forrester Research, cautioned that too many of these Unix programs are just too high-end for the Mac. "How many consumer, entertainment or multimedia apps out there were built on Unix in the first place?" he asked. "Where the Unix family capability is interesting is where someone has interest in the Apple market." Still, Kerris sees cautious to boisterous enthusiasm for Mac OS X from other Unix developers. "They know as desktop machines become more and more powerful they want to be able to reach a broader market, but they haven't been able to do that in a Unix environment," he said. "Mac OS X could help change that." McAfee, an antivirus software maker and a unit of Network Associates, has already seen the advantage of having Unix at the core of Mac OS X. While competitors struggled to move their existing antivirus programs to the new operating system, McAfee delivered a beta within days of Mac OS X's release. How? "The Mac OS X product is heavily borrowed from our Unix code base," said Ryan McGee, McAfee's desktop product marketing manager. Still, McAfee would have preferred moving its existing Mac product to Mac OS X. That's because "providing an always-on virus-scanning component is a big, big job," McGee said. He partly blamed Apple for the situation, which the McAfee could never have tackled quickly without its existing Unix product. "We all needed some more stability in terms of the kernel and the underpinnings of the OS earlier in the process," he said. That would have pushed development ahead faster, he emphasized. While McGee is happy with the current set of development tools, Kerris said that Apple has "more to do" if it wants to win over Unix developers. "They need to get a lot more of the developer tools out there," he said. The problem is one of programming languages, with Apple not backing the more popular C and C++ languages. "They need to find the tools that can merge the two environments or help people come from the C, C++ world into the OS X world," he said. Apple's biggest inroads into the Unix community may not come from developers but from the education market, say analysts. "I'm starting to hear some buzz from higher education," Gartner analyst Michael Silver said. "Some schools told me they have Unix users that really like Mac OS X a lot and see tremendous synergy." This makes sense to Gillett, who said the education market offers two advantages: Many K-12 schools use Macs, making Mac OS X an attractive fit. At the same time, he said, "Unix is extremely popular in higher education." But Apple's Schiller sees a different kind of appeal. "Education, and particularly higher education, believes in open standards," he said. This particularly important with BSD Unix's appeal, he added. Kerris sees a huge opportunity for Apple, particularly in selling against Windows or Unix. "You end up with: 'I learned on a Mac and I grew on the Mac' instead of 'I learned on a Mac and grew to Unix or some other operating system,'" he said. "It was inevitable that somebody would bring a standard Unix operating to the desktop and take advantage of the applications there." Have your say instantly, and see what others have said. 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