Apple announced Mac OS X Lion with considerable fanfare at its Back to the Mac event last October, and now it's dropped the first developer preview on the world -- giving us a chance to sample some of the big cat's new features and UI concepts. We installed the dev build on one of our MacBook Pros and used it over the weekend, and while we won't be able to see any huge changes in day-to-day workflow until our favorite apps are updated to take advantage of Lion, we did see plenty of interesting system-level features and additions -- and yes, iOS's influence is all over the place. Read on for a full breakdown of what's new!
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Mac OS X Lion hands-on preview


Launchpad


Apple's making a big deal out of Launchpad, Lion's new iOS-style app launcher, but we're assuming most power users will stick to the Finder, Dock, and Spotlight for quick access to frequently-used apps. We're guessing less-advanced users will love it, though -- it mimics the successful iOS app interface to a tee, including folder support and direct app installs from the Mac App Store.

Full-screen apps


Another feature that seems destined to be ignored by power users and beloved by the masses, Apple's pushing hard for developers to build full-screen app views for Lion. It's an idea that fits some apps much better than others -- iPhoto and Safari work well in full-screen mode, but opening iCal fullscreen on our 27-inch iMac was positively silly. Switching an app to full screen opens it in a dedicated space by default, so you can quickly switch between the desktop and open full-screen apps with a three-finger swipe -- a move that mimics the multitasking gestures Apple's been testing in iPad iOS developer builds.

Mission Control


While Launchpad and the focus on full-screen apps feel aimed at the casual user, Mission Control feels like the exact opposite -- a feature only a power user could love. It's basically a unified management UI for Expose and Spaces that comes up with a three-finger swipe up, and while it works well for what it is, it doesn't really reduce any complexity -- it just makes it all easier to see at once. That's useful enough, we suppose, but the Dock, command-tab app switching, and the multitasking gestures all feel more efficient than dropping into Mission Control thus far.

Multitasking and app management


One major change Apple's made in Lion is that running apps are no longer denoted by a little "light" in the Dock. Just like iOS, Lion is designed to manage system resources for the user, in an effort to make multitasking completely seamless. That means the system can "freeze" apps in the background, kill processes, and otherwise do whatever it takes to preserve the user experience. It's a nice idea, and we're sure some people will love it, but we'd rather take destiny into our own hands when it comes to managing apps -- so it's a good thing you can always see what apps are running by hitting control-tab or by turning the lights back on in preferences.

Gestures


Lion introduces a number of new multitouch system gestures that make using the OS with a trackpad much more natural and smooth. We're not sure how these gestures will map to a Magic Mouse (which really only works for single- and two-finger gestures) or a standard mouse, but if there was any reason for desktop users to invest in a Magic Trackpad, Lion is it. Some highlights:

Swipes and scrolling

Three-finger swipes are everywhere in Lion -- a swipe to the left to switch between Spaces and full-screen apps, a swipe down to show app windows, a swipe up to show Mission Control, a swipe right to show the Dashboard space. You can also pinch in with four-fingers (really, three fingers and your thumb) to bring up Launchpad, and pinch out to show the desktop. All of these can be customized, of course, but it's definitely notable that Apple's enabling multitouch trackpad gestures as a default navigational tool.

Two-finger gestures have been slightly changed as well -- horizontal swipes now control back / forward in Safari by default, and scrolling is now inverted by default, as in iOS. (You can switch it back to regular, thankfully.) There's also a new preference that basically rids the system of scroll bars if you're using a trackpad, instead showing an iOS style vanishing scroll indicator.

Pinch to zoom

Pinch-to-zoom in Safari is now just like Mobile Safari in iOS -- it smoothly zooms the whole page, instead of just bumping sizes at fixed increments. It's interesting, but it feels a bit half-finished -- we caught some stuttering and artifacts here and there. We're assuming Apple will clean this up before release.

Versions and Auto Save


You might think of Versions and Auto Save as Time Machine for apps -- Lion apps automatically save changes to documents as you work, and then you can browse between saved versions using a variation of the Time Machine interface. It's nifty stuff that worked really well when we tested it in TextEdit, although we'll see how well it performs with heavyweight media files.

AirDrop

One of Lion's niftiest new features is AirDrop, which allows quick and easy file transfers between WiFi-equipped Macs. Opening the AirDrop panel in the Finder makes your machine discoverable to other machines with AirDrop open, and swapping files is as simple as dragging and confirming. Although it uses WiFi, you don't need a router to use it -- the WiFi chips in most newer Macs are able to rapidly switch back and forth between AirDrop and a standard network connection. Apple hasn't said what the oldest machine with AirDrop support is, but we get the feeling even machines that are several years old will be able to use the feature.

Resume


Another pickup from iOS, apps are now able to save state on exit and pick up right where they left off. This ties in with the new multitasking management -- even if the system exits an app to free up resources, resume means it'll look like nothing ever happened when you open it again. Obviously this strategy has been used to great effect in iOS and Android (and eventually in Windows Phone 7), but we'll see how it plays out on the desktop, where apps use vastly more memory and storage.

App updates


Apple's redesigned a number of of built-in apps in Lion, and the iOS influence is readily apparent -- run some of these apps full-screen on an 11-inch MacBook Air and you'd be hard-pressed to tell the difference from an iPad. Some highlights:

Mail

The venerable OS X Mail app has been given a major UI makeover in Lion, picking up a number of elements from Mail in the iPad. You've got a left column with all your messages and a preview pane on the right -- threaded messages are numbered in the new conversation view, which is a dead-simple idea that works really well. Search has also been dramatically improved with easy query-stacking options, and folders can be added to a new bookmark bar-style Mailbox Bar at the top fo the screen.

Address Book

The Address Book app now looks like a book, and the cards are much cleaner. It's cute, in its way.

iCal

iCal has been given a thorough makeover as well, with a new fullscreen mode and some new features, like an availability view that plots out all your free time in a day.

QuickTime
Snow Leopard's QuickTime X was relatively feature-poor, but almost everything that went missing from QuickTime 7 is back in Lion, including editing support and better export options -- including built-in support for Vimeo, Flickr, Facebook, and Mail.

New preferences and other changes


Lion has a number of new iOS-inspired options in System Preferences -- nothing major, but some are worth pulling out.

Privacy

A new addition to the security pref pane -- just like iOS, you can control location services globally or on a per-app level, and you can also turn off reporting crashes to Apple.

Internet accounts

Just like iOS, you can set up accounts for MobileMe, Gmail, Exchange, Yahoo, and AOL all from a central preference pane -- the settings are used in Mail, iCal, iChat, Address Book, and other apps.

Disk Encryption

FileVault has been completely re-done in Lion -- it now encrypts the entire disk, not just your home directory.

Other changes

A couple things we noticed that may or may not make the final release: Front Row appears to have been stricken from Lion, although hints of it still remain in the odd preference dialog, and 9to5 Mac found evidence of multiple-user remote desktop, which would let you log into your machine and control your account's screen while someone else is physically logged in and using their account. That would be pretty slick if it makes the final cut. We've also seen evidence of Yahoo video chat support in iChat, and Preview has the ability to append an image of your signature to PDF files, which sounds like it'll be a godsend if it works.

Wrap-up



Obviously we've only just scratched the surface of Lion in this preview -- most of Lion's changes come under the hood, and we haven't even touched on things like the lack of Rosetta support, the optional Server package that now comes with every OS X install disc, and the million other features that have been tweaked or added in this release. But even just by skimming the surface, it's obvious that Apple's working hard to bring iOS-style computing to the desktop in a major way, starting with an almost exclusive focus on the multitouch trackpad as an input device and carrying through to how multitasking is implemented and managed by both the user and system. We'll have to wait for a final version to review all these changes in practice and evaluate them as part of an actual workflow, but we've got a feeling we'll see quite a few of these links between iOS and the Mac get drawn in more strongly by the time Lion actually ships -- and we wouldn't be surprised if the next move comes in the developer preview of iOS 5 we're hoping to see on Wednesday.