Over the next three months, we'll be looking at Mac OS X, the next-generation operating system from Apple that's due in early 2001 (although a public beta will be out sometime this year).

Although it's dubbed X (as in 10), this really isn't an update of the venerable Mac operating system (which is up to version 9), but a whole new critter. I don't exaggerate when I say that the company has a lot riding on this baby. It will define the Mac environment for years to come.

Apple is attempting the tricky feat of melding aspects of the traditional Mac OS with a new, fluid appearance, and overlaying it on a Unix core. The goal is to build an eye-popping, friendly graphical user interface that will appeal to iMac users and serve as a front end to a powerful, complex engine that power users will love.

The aqua interface

Aqua windows sport gel-like, proportional scroll thumbs; colored jellybeans (or perhaps they're gems) for title-bar widgets; and bright "traffic light" buttons. Yes, the traffic light analogy is deliberate. A red button stops (closes) a window. A green button tells it to go (zoom). And a yellow button slows (shrinks or minimizes) a window.

Transparency is also used extensively in the Aqua environment. Traffic widgets and windows cast transparent shadows on windows behind them. If you unselect pull-down menus, they fade away rather than immediately disappearing.

Aqua also changes the Mac OS view of icons. For 15 years, computer operating systems have used 32-by-32-pixel icons, which were designed for low-resolution displays. But because display sizes and resolution levels have increased, Apple says Aqua sheds these constraints by making available large (up to 128-by-128 pixels), colorful, photo-quality icons. The larger size makes the icons more attractive and legible, offers a broader canvas for more photo-quality detail, and provides better document previews in the Finder, according to Apple.

Mac OS X reduces multiple-window clutter by focusing most of its applications in a single window. The new Finder (the Mac desktop), Mail (OS X's system-level e-mail application), and the system-preferences panel live together harmoniously in a single window.

An optional single window mode is designed to save onscreen real estate. In this mode, which can be disabled, your Mac makes the current window the active window and automatically hides all the other open windows. When you want to work on another document or application, your Mac automatically removes the currently active document and makes the desired document the only active document on the screen.

Mac OS X introduces new panels that attach themselves to documents and "make their relationship clear," according to Apple. You can even have multiple interleaved documents, each with its very own Print or Save panel, open simultaneously. Plus, you can leave dialog panels open and go to other tasks; in the current Mac OS, a dialog panel demands your immediate attention and won't go away until you respond. The new panels fluidly slide out from a window's title, and have a translucent quality that makes them appear as if they're floating above the document.

The dock

One of the most controversial features of Mac OS X is the Dock, a box that sits at the bottom of your screen. The Dock holds folders, applications, documents, storage devices, minimized windows, QuickTime movies, digital images, URLs, and other stuff you want instant access to. The Dock is sort of a combination of the Apple Menu, the Launcher, and the Control Strip present in the current Mac OS.

And for many Mac users, that's the rub. While everyone who has used it admits that the Dock is extremely user-friendly, they say it lacks the power and flexibility of the features it replaces. While the Dock may be fine for novice users, many longtime Mac users want more customization potential than the new device provides. (Of course, some of the missing features could return, or the Dock itself could see some major revisions before the final version of Mac OS X arrives.)

The Dock displays an icon for each item you store in it. These icons provide feedback about the items they represent. For example, the icon for Mail tells you if you have any new messages waiting to be read. If you store an image, the Dock shows it in preview mode, so you can tell what it is without opening it.

In a Launcher-like feature, switching between tasks involves clicking the application or document icon you want to start using, so it becomes the new active task. You can choose to minimize an open window and have it become an icon in the Dock. Because running applications can be minimized into the Dock, a quick look at the bottom of the screen tells you what applications you're currently running. Click a docked icon and it maximizes if it's a window or opens if it's an application or document.

As you continue to add items to the Dock, it expands until it reaches the edge of your screen. Once it hits the border, the dynamically scalable Dock icons shrink proportionately to accommodate additional items. To make the smaller icons more legible, Apple has included a new feature called magnification. Pass your mouse over the icons, and they magnify to a preset maximum resolution of your choice, up to 128-by-128.

If you move your mouse over an icon in the Dock, its name "floats" above into view. In fact, the Quartz graphics engine (which we'll get to in a moment) provides an impressive "genie" effect in which windows flow to and from the Dock if they're minimized or maximized.

The new finder

Mac OS X will have a Finder. The first thing about it that will jump out at longtime Mac users is that has a new navigation interface, as well as the fact that it's totally contained within a single window.

In the new Finder, you jump to the most-used sections of your Mac via large buttons. For instance, if you click on the Home button you're transported to your Home directory. This directory can be located on your hard drive or on a network (the File Viewer knows the location of said directory). The aforementioned buttons offer quick access to applications, documents, favorites, and-new with Mac OS X-the people with whom you often communicate.

Sporting the Aqua interface style, the OS X Finder's icons are continuously scalable, just like icons in the Dock. And the Finder browser has a Back button and an integrated Search field, two new goodies.

The new Finder has a File Viewer that offers three different options for viewing your file system. Apple has retained the traditional icon and list views from Mac OS 9, while, in their words, improving their behavior to reduce screen clutter and provide better navigation feedback. Now double-clicking on items in the icon or list views no longer brings up separate windows. Instead, the view on the new folder replaces the view on the old folder within the single File Viewer window. Apple says by focusing the file system into a single window view, Mac OS X makes smarter use of screen space and eliminates the problem of proliferating windows.

The File Viewer not only provides a view into your hard disk, it's now the only interface you need to access all resources connected to your computer: externally connected storage devices like FireWire and USB hard drives, CD-ROMs, digital cameras, even the Internet. The company has also made the network an extension of the file system by incorporating it into the File Viewer.

Better graphics with quartz

The graphics engine of Mac OS X is known as Quartz and is based on Adobe's Portable Document Format (PDF), a superset of PostScript. PDF has several advantages over PostScript, including better color management, internal compression, font independence, and interactivity. And hey, PDF is also a free and open-standard, which saves Apple from paying PostScript licensing fees.

Using PDF, the new Quartz 2D graphics system delivers on-the-fly rendering, anti-aliasing, and compositing of PostScript graphics. Apple says Quartz will result in pristine onscreen graphic elements that will be sharper than ever before, even when their size is increased.

You can see the power of Quartz in the Mac OS X Aqua interface itself. Using Quartz's compositing engine, Aqua creates translucent controls and menus, and gives the system visual depth with drop shadows around the edges of windows. And Apple has included built-in support for PDF, which means you can embed and manipulate PDF data with any Mac OS X application-and even "Save to PDF." This means that you can create Quartz-enhanced, graphics-rich documents.

Apple says that since this capability is available to all Mac OS X applications, Mac developers have a whole new palette of creative tools. Of course, much of this functionality is available to current Mac OS users through vector-graphics applications. But Quartz moves the functionality into the OS itself.

Though Apple has adopted PDF as the default file format for storing graphics in Mac OS X, it's still not entirely clear how Apple will implement PDF. However, Apple does intend to provide basic PDF capabilities built on the published specifications of the PDF 1.2 file format. The company is also counting on third-party developers to extend this architecture to cover vertical market segments.

Next month, we'll peek under the hood of Mac OS X at such "modern" OS features as protected memory, enhanced virtual memory, and multithreading.

Contributing Editor Dennis Sellers writes and edits for several Mac-specific publications.