This week, Apple released a developer preview of Mac OS X 10.7 ("Lion"), the next evolutionary update to the company's aging desktop OS. As Apple notes, Lion takes many design cues from the company's iOS system--used in the iPhone, iPod touch, and iPad products--which I think makes plenty of sense. In fact, I think history will show that Apple, through luck or intuition, did the right thing by basing its mobile OS (iOS) on the same technical underpinnings as its desktop and server OSes (OS X), and this is the next logical step.

Microsoft, of course, will soon follow Apple--as it often seems to--by melding its own desktop and server OSes (Windows) with its mobile OS (Windows Phone OS) in Windows 8. But you don't have to share common technical underpinnings in order to share ideas in a common sense way between products. And given the legendary OS competitions between Apple and Microsoft, I think it makes sense now, as always, to examine both sides of the coin and see where each could benefit from the innovations first offered by the other. In this case, specifically, I'm looking at the Lion developer preview and trying to imagine how Windows would most benefit from some of the designs Apple is now pursuing.

Some of these are specific to Lion, but a few are general to Mac OS X as well.

One SKU. I've harped on this a lot in the past, but in a bid to maximize profits, Microsoft has littered the market with far too many Windows product versions, or what the company calls SKUs (for "stock keeping unit," retailing term). And while we can try to dumb down the conversation by explaining how, in any given market, customers only have two or three or four choices, or whatever, the fact remains: One version is not just enough, it's optimal from the customer point of view. Just ask Apple: It offers just one version of Mac OS X. It's called Mac OS X. Not Mac OS X Media Center Edition or Mac OS X Arbitrarily Limited Edition. Just Mac OS X.

Currently, Apple really makes two versions of Mac OS X, one for Mac desktops and laptops (Mac OS X) and one for servers (Mac OS X Server). But I see something in the Lion developer preview that just makes my heart weep: It includes both the client and server versions in a single install, and the server code is actually installed as if it were a feature or add-on for client. Oh my. Now, as unlikely as it is that Apple would ever ship the final version of Lion in this same configuration, you have to dream. Come on Microsoft. I don't really expect you to reduce your product lineup to a single product version. But you could make it simpler. A lot simpler.

(Update: Actually, it appears that Apple does intend to integrate Server as a feature in OS X Lion. Nice! --Paul)

Better resolution agnosticism. Microsoft has been talking about resolution independence for a long time, but the fact remains that the Windows GUI is built on resolution-dependent bitmap graphics. So onscreen elements are whatever size they are, and while some offer a few different versions, the built-in controls for enlarging UI controls has always been hokey at best.

Mac OS X, like Windows, is built with bitmaps, and not resolution-independent vector graphics. Despite this, Apple's OS achieves a graphical and textual fidelity that simply isn't possible in Windows, and it handles growing (and shrinking) key UI elements better than Windows, while offering this functionality on the fly. Case in the point: The Mac OS X Dock, which, while horrible as a task switcher, has an easily sizable interface. The Windows taskbar, by comparison, provides two options: Normally sized and ugly.

Apple's success here isn't ideal, and it's really just based on a bit of subterfuge: The onscreen elements in OS X are simply drawn in a bigger size, natively, and thus can be resized over a wider range of sizes. So here, I'm not suggesting that Microsoft copy Apple, I'm suggesting that they really make the Windows UI resolution independent and more scalable.

Simpler, touch-friendly controls. I've always felt that OS X's "lickable" Aqua UI elements--buttons, scrollbars, and so on--were terrible, just awful looking. And now in Lion, they're being replaced, finally, by simpler looking controls modeled after the controls in iOS. Knowing Apple--the company has never been good about consistency--this work will only be partway implemented in Lion, and we'll see some weird mix of Aqua and newer-type controls even in the built-in apps. But it's a start.

In Windows, Microsoft's only real nod to modernity in the UI is that onscreen controls are automatically made a bit bigger when Windows detects touch-capable hardware. But because Windows was designed for lower resolution screens and a mouse and keyboard interface, this tacked on system is just a stopgap. What's really needed is simpler, more modern UI elements that work equally well for touch as well as legacy interaction techniques.

So ultimately, this is really just a continuation of the previous item, since making the UI resolution independent would solve this issue as well.

Get the Recycle Bin off the desktop. This is a small thing, maybe, but it's always bothered me. In Mac OS X, the Trash is available on the Dock, so it's always available, no matter how many windows you have cluttering the screen. But in Windows, the Recycle Bin is on the desktop, where it can easily be obscured by windows. Yes, you can also press Delete. But many people work solely with the mouse, and the Recycle Bin needs to be available--i.e. viewable as a target--at all times. Thus, it needs to be integrated into the Windows taskbar. Simple.

Simpler app launching. One of Lion's more controversial features is a dumbed-down UI overlay called Launchpad, which presents all of the system's available applications as a grid of icons, just like on the iPhone. This type of thing may seem silly to readers of this site, and is likely causing groans within the Mac community too, but remember that most computer users aren't power users. And to those "normal" people, simpler is almost always better.

And remember, when you look at modern desktop OSes like Windows and Mac OS X, finding out which apps are available on a given PC is surprisingly difficult. On Windows, you can find these apps pinned to the taskbar, pinned to the Start Menu, in the All Programs section of the Start Menu, and of course within the file system itself as well. That's a lot of ground to cover.

On simpler systems, like smart phones, the user doesn't typically deal with a file system, let alone multiple places to find apps. Instead, there's usually some simple UI, a single screen or set of screens, with one icon for each app. Launchpad does this for Lion, replicating the contents of OS X's Applications folder in a grid of onscreen icons. As with the iPhone, if you have too many apps, multiple screens are used, and you can scroll between them using gestures (if you have a compatible pointing device like the loathsome Tragic Macpad).

Launchpad isn't completely seamless; it disappears when you launch an app and isn't there waiting for you when you close that app. But because OS X, as a full-fledged desktop OS, supports small, floating windows in addition to full screen windows that hide everything else, the experience can't duplicate the iOS UI completely. And that's fine. The point is, it takes a simple app launching UI that is well-known to users (more of whom have iPhones and similar devices than do Macs, by the way) and brings it to Apple's more powerful platform.

What would something like this look like on Windows? Obviously, Microsoft should utilize the app launching mechanism it employs on Windows Phone. And not surprisingly, that is exactly what the software giant is doing: As I exclusively reported previously, Microsoft is bringing an alternative tiles-based user interface to Windows 8, and that UI can be used like Launchpad is in Lion, but also can replace the "normal" Windows UI on smaller devices like tablets, slates, and phones (in the future).

Simpler app discovery, installation and maintenance. Mac OS X Lion will include an integrated App Store, and Mac users now have access to a beta version of the store in the current version of OS X. It works very well, as I noted in my overview of the store, and offers a number of features that are hugely valuable to users, including app discovery, integrated downloading and installing, integrated updating of apps, and licensing that allows for one app purchase to be used across any number of supported devices. It is, in other words, the model for what Microsoft needs to do in Windows as well.

Microsoft's app store infrastructure is already in place, of course, in the form of what's called the Microsoft Marketplace internally. Externally, this storefront exposes itself in different ways, and offers different content. On Xbox LIVE, for example, it's called Xbox LIVE Marketplace. Zune users can access the Zune Marketplace. Windows Phone users get Windows Phone Marketplace. And so on.

Windows 8, of course, will include its own storefront, mostly likely called Windows Marketplace (though that name was used previously and discontinued; for that reason I suspect they may simply go with Microsoft Marketplace). And like the Apple variant, Microsoft's store isn't just about providing yet another place to find free and paid apps. Instead, it will also serve as the discovery and delivery vehicle for a new kind of native Windows app, codenamed Jupiter and based on Silverlight. These apps will be delivered as packages, as are OS X apps, which are essentially compressed folders that contain the app and all necessary secondary files. These self-contained app packages will bridge the gap, technologically, between today's desktop apps and the types of apps created for Windows Phone.

And let's not forget what I consider to be the number one advantage of Apple's App Store: When you buy an app, you own it. It's not tied to one PC, or one device, as is normal for Windows apps. It's tied to you, via an account of some type (iTunes, in Apple's case) and is yours forever. You can install it again and again. And we need this on the Windows side. This has to be part of the deal.

What Apple could learn from Windows

Of course, this learning isn't a one-way street. There are numerous aspects to Microsoft's Windows OS that are superior to anything in Mac OS X, and that will be true when Lion ships later this year as well. I'm not particularly interested in helping improve Apple's OS, but a few things do leap to mind.

Seamless full screen for all apps. Because of the design of Mac OS X, which features a non-removable, non-hideable, system-wide menu bar at the top of the screen, Apple's desktop OS has never done a good job of handling truly full screen windows. This is changing, slowly, first via the iLife '11 apps, which do mostly feature full screen capabilities, and then in Lion, where built-in apps will (mostly) feature a full screen mode. That's good news.

However, Apple's support of full screen apps will always lag behind that in Windows because the feature has been tacked on after the fact. Looking at the Lion developer preview, for example, and there's no keyboard shortcut for causing an app to go into full screen mode, whereas in Windows this is a universally supported feature. And because full screen hasn't been part of the OS so far, no third party apps support this feature--or whatever keyboard shortcut(s) may or may not be coming. So you'll need to update them to get this, assuming its ever added at all.

I've always felt that OS X's use of a system-wide menu bar was a mistake, because it steals onscreen real estate even when it's not needed. And now, we can see another reason why this is bad design. Even in Lion, full screen capabilities for apps will be a mixed bag.

Marking progress with a time estimate. While installing the Mac OX Lion developer preview, I saw something that made me smile (and not in a good way): The installer actually displayed a "time remaining" progress indicator. We used to do this in Windows, too, back in the Windows 98 days. And the reason Microsoft doesn't do this anymore is that such predictions are always woefully wrong. So I was told that this thing was going to take 30 minutes, and then 37, and then 23, and then 32. And it took about an hour. Point being, don't predict the time, Apple. Just display a progress bar.

Messy window management. For an OS that is incorrectly described as being "easy to use" and "intuitive," Mac OS X has picked up a lot of crazy cruft over the years. And the best example of this stuff is the myriad of window management utilities that have cropped up. I'm sure there are 6 or 7 power users somewhere who actually use this stuff. But separate UIs for features like Exposé, Dashboard, and Spaces is, well, insane. And there's no way normal people are using this stuff. They're indiscoverable, inscrutable, and hard to learn.

In Lion, it gets worse. Now there's yet another UI, called Mission Control, which Apple describes as "a powerful, entirely new feature that unifies Exposé, Dashboard, Spaces, and full screen apps." Blech. And how do you bring up and use this little wonder? Apparently, you do so via a gesture, so you better have a compatible pointing device. It's likely that there are other ways, of course. But they're not visible in the UI anywhere. So like the features it's meant to corral, Mission Control (in its current form) is also indiscoverable, inscrutable, and hard to learn.

So, the issue here is simple: With Mac OS X, the user can do any number of crazy things, opening up windows, workspaces, gadgets, and other stuff. On a smart phone or device, you can run apps, and they're always full screen. So bridging the gap between these two very different environments is difficult, perhaps impossible. Mission Control seems designed for this purpose. But its unclear how users are supposed to know it's there. On a device, of course, the presence of a dedicated Home button makes it easy to return to the list of available apps and, with a double-tap, view the list of running apps. On a Mac or PC, things are more complex. (Note that Apple is using a dedicated button on its Mac keyboards to trigger this environment as well.)

Features in Mac OS X Lion that we already have in Windows. It's worth pointing out that quite a few of the new features in Lion have been available in Windows for years. For example, Lion is adding full-disk encryption to FileVault; that was added to Windows in 2006 as part of Windows Vista. (It's called BitLocker.) Lion includes a feature called AirDrop, which lets users "copy files wirelessly from one Mac to another with no setup"; this is essentially a dumb version of Windows Live Mesh. Versions, a new feature that "automatically saves successive versions of your document as \\[its created\\]," is of course Apple's version of Previous Versions, which we've had since Vista too. (In fact, the server-based version of this dates back to Windows Server 2003, from almost a decade ago.) And the new Mail layout, while modeled after Mail in iOS, utilizes a paned UI that Microsoft's been using in Hotmail, Outlook, and Windows Live Mail for several years.

Final thoughts

This is just the beginning of what could be a very long conversation, of course. Apple likely has more features planned for Lion than are exposed by the developer preview, and of course future Mac hardware could provide special buttons and keys that make some of these features less inscrutable. More important, for Microsoft (and Windows users), there's a lot of interesting UI work being done on the other side of the fence, most of which is aimed at making the computing experience simpler. This is important work: While Apple's UIs aren't perfect, the company has done a better job of making simple devices, in particular, than has Microsoft. If it can bring this expertise to more powerful computers successfully, there are lessons there for all of us. I'm not suggesting that Redmond should "start its photocopiers"--after all, the copying has always gone both ways. But I am suggesting that those on the Windows side of the fence need to collectively pay more attention to what Apple gets right.