• PC World
• »Software
• »Operating Systems

Don't call Apple's new operating system Mac OS "Ex." Apple wants you to call it Mac OS "ten," possibly to prevent the word sex from rolling off your tongue as you say it. That effort is not likely to succeed: The Mac platform's beautiful new interface is as sexy as they come--and it has a brand-new high-performance engine to match.

In the past, Windows has often borrowed from the Mac OS. This time, Apple takes some cues from both Windows and Unix. For example, it includes a new dock reminiscent of the Windows taskbar (but better looking). On the minus side, the new operating system discards some favorite features from previous versions. We examined the public beta of the OS, which Apple plans to ship by early next year.

Mac Meets Unix

Thanks to the Unix platform on which it's based, OS X promises a faster, more stable Mac. Preemptive multitasking lets you run several operations at once, such as beginning an intensive database query and then switching over to your e-mail application. Symmetric multiprocessing makes more-productive use of multiple processors, and protected memory allows the system to keep running even if one app crashes. Various versions of Windows offer some or all of these attributes.

To take advantage of these new features, however, developers must update their applications--and unfortunately, the list of X-compatible apps is painfully short. But most of Apple's core developers (including Adobe, Macromedia, and even Microsoft) have committed to updates.

In the meantime, Apple says, the majority of existing applications do run on OS X but can't use its new features. Our tests confirmed this. When we installed Mac OS X on a Power Mac G4 Cube with one 450-MHz G4 processor and 128MB of RAM, individual applications crashed periodically, but never the entire system. And though our beta ran slowly, we could perform multiple tasks simultaneously, such as starting up a couple of applications, copying files, and closing windows. But most older peripherals needed new drivers to work at all.

In the stunning new "Aqua" interface, dialog boxes and drop-down menus are semitransparent--where they overlap solid objects, you can see through them faintly (a feature we'd love in Windows).

A Perfect X

In window title bars, three little gumdrop buttons in the upper left corner glow red, yellow, and green, respectively, when you pass your cursor over them. They close, minimize, and maximize your window, just as the corresponding buttons in Windows do (the old operating system let you roll windows up under their title bars, not minimize them).

The dock at the bottom of the screen functions similarly to Windows' taskbar, but it can also house favorite applications. As you run your cursor over the icons in the dock, they grow beneath it. Click on an icon in the dock, and it bounces gently up and down a couple of times until the app is up and running. Luckily, you can adjust the level of icon magnification to the size you like, shrink the size of the bar, or autohide it if you find all the movement distracting.

Other departures may faze some users. The old Mac OS used a vertical hierarchy in file windows (similar to the left pane of Windows Explorer); OS X adopts a horizontal hierarchy. Old-timers may miss the familiar Apple menu, which included useful features such as menus for recently used applications, servers, and documents. File names are harder to read than they were in the old Mac OS.

But if gaining an operating system that performs better and doesn't crash means sacrificing some old comforts, many Mac users are likely to jump quickly from the dinghy to the speedboat. Mac OS X could even attract some Windows users looking for a chic alternative, as long as they're comfortable with a shorter list of available applications. If Apple doesn't convince the developers to join up, we can only hope that Microsoft's designers take note of OS X's style innovations.