Mac OS X Lion

Mac OS X Lion (version 10.7; marketed as OS X Lion) is the eighth major release of Mac OS X, Apple's desktop and server operating system for Macintosh computers.

A preview of Lion was publicly unveiled at Apple's "Back to the Mac" event on October 20, 2010. It brings many developments made in Apple's iOS, such as an easily navigable display of installed applications, to the Mac, and includes support for the Mac App Store, as introduced in Mac OS X Snow Leopard version 10.6.6. On February 24, 2011, the first developer's preview of Lion (11A390) was released to subscribers of Apple's developer program. Other developer previews were subsequently released, with Lion Preview 4 (11A480b) being released at WWDC 2011.

Lion achieved golden master status on July 1, 2011, followed by its final release via the Mac App Store on July 20, 2011. Apple reported over 1 million Lion sales on the first day of its release. By October 2011, Mac OS X Lion had sold over 6 million copies worldwide.

Release and distribution
On June 6, 2011, at the Apple Worldwide Developers Conference, it was announced that the official release for Lion would be in July 2011. The specific release date of July 20 was not confirmed until the day before, July 19, by Apple CFO, Peter Oppenheimer, as part of Apple's 2011 third-quarter earnings announcement.

Apple did not initially announce any physical media distribution for Lion, such as a set of CD-ROMs or a DVD-ROM as used for past releases. Instead, the operating system was said to be available exclusively as a download from the Mac App Store for US$29.99. The only prior version of OS X that supports the Mac App Store is Snow Leopard, which implied that any machines that support Lion currently running Tiger or Leopard would first have to be upgraded to Snow Leopard, as opposed to allowing a direct upgrade to Lion.

Apple later announced two alternative distribution mechanisms for the benefit of users without broadband Internet access: in-store downloads at retail Apple Stores, and a USB flash drive containing the OS, priced at US$69, available through the online Apple Store beginning in August. It is not clear whether the USB distribution will support a direct upgrade to Lion from OS X versions prior to Snow Leopard. On August 4, 2011, Apple started to take orders for Mac OS X Lion's USB installation flash drives for $69.99.

The Server portion of Lion is available as a separate download from the Mac App Store for US$49.99, which is in addition to the purchase price of Lion itself.

Hardware support
The first developer preview of Lion added TRIM support for SSDs shipped with Macs, which is also included in the latest version of Snow Leopard (10.6.8) shipping with current MacBook Pros before July 20, 2011. As of yet, there is no TRIM support for other SSDs.

System requirements

 * x86-64 CPU (Macs with an Intel Core 2 Duo, Intel Core i3, Intel Core i5, Intel Core i7, or Xeon processor.)
 * At least 2GB of RAM
 * Mac OS X 10.6.6 or later (Mac OS X 10.6.8 is recommended)
 * 7 GB of free hard drive space is recommended
 * AirDrop is supported on the following Mac models: MacBook Pro (late 2008 or newer), MacBook Air (late 2010 or newer), MacBook (late 2008 or newer), iMac (early 2009 or newer), Mac mini (mid 2010 or newer), Mac Pro (early 2009 with AirPort Extreme card and mid 2010 or newer).

New or changed features
Some new features were announced at the "Back to the Mac" keynote in October 2010, and the Apple website was updated in February 2011 with more details. Other features were announced at the WWDC 2011 keynote or on Apple's Mac OS X Lion Web site after the keynote. Apple states that there are over 250 new or changed features in Lion, including:


 * Address Book now uses an iPad-like user interface. It also includes improved Yahoo support and FaceTime calling.
 * AirDrop – Lion-to-Lion direct file sharing via Wi-Fi Direct. No wireless access point required.
 * Address space layout randomization – Address space layout randomization (ASLR), a security technique that puts important data in unpredictable locations, making it harder to target known weaknesses, is available for 32-bit applications, and "has been improved for all applications", in Lion.
 * Apple Push Notification Service – Send over-the-air alerts, such as news updates or social networking status changes, using Apple's Push Notification service to applications that support APNS. APNS allows Mac OS X Lion and iOS clients to receive push changes to items such as mail, calendar and contacts from a configured OS X Lion Server.
 * Auto-correction now behaves much like on iOS devices, displaying an iOS-like popup box.
 * Auto Save – As in iOS, documents in applications written to use Auto Save will be saved automatically so users don't have to worry about manually managing their documents.
 * Emoji support – Apple has added a new Emoji font commonly used in chat to express ideograms.
 * Exposé in the Dock, a way of activating Exposé for a single application from the Dock, a feature added in Mac OS X Snow Leopard, is altered. One must now double-tap with two fingers on a dock icon to initiate single application exposé, or simply right-click or control-click and select Show All Windows.
 * FaceTime comes bundled with Lion.
 * FileVault now offers full disk encryption and added security with XTS-Advanced Encryption StandardA 128 data encryption. Support for FileVault on external hard drives has also been added.
 * Finder improvements – Finder search allows multiple search criteria to be specified without creating a smart folder, Finder search offers suggestions, files can be grouped by various attributes, and one can now merge files under two folders with the same name – a prompt will appear asking whether one wants to replace or keep both files.
 * Font Book 3—Font Book 3 now provides more flexible displays of character glyphs supplied by a particular font face. Duplicate font files are now flagged with a warning icon, and can be fixed automatically or resolved manually.
 * Full-screen apps – Native, system-wide support for full-screen applications running in their own space. Supporting applications display a new button at the top right of application window, this button opens applications in full-screen mode.
 * High-quality multilingual speech voices – users can download new high-quality voices in more than forty languages and dialects.
 * iCal has an updated user interface, an annual view, and support for a full-screen view.
 * iChat now has support for logging into Yahoo! Messenger. Users can audio- and video-chat with other iChat users using their Yahoo! accounts.
 * Languages/Localization – Arabic, Czech, Turkish and Hungarian are added as full system languages, to make the total number of twenty-two languages available in Mac OS X.
 * Launchpad – An application launcher that displays an iOS-like icon grid of installed applications. It features the ability to make multiple pages and group apps into folders that function the same as folders in iOS.
 * Mac App Store – An application store built in the image of the iOS App Store. Like in iOS, it will provide ways for shoppers to discover apps, one-click installation of apps, and one-click updates of all or selected installed applications. Despite being announced as a future feature of Lion, the Mac App Store was released for Mac OS X Snow Leopard on January 6, 2011 as it was bundled with the Mac OS X 10.6.6 update.
 * Mail – Uses an iPad-like user interface, has a fullscreen-optimized view, uses chronological "Conversations" to organize messages, and supports Exchange 2010 (but not through the Exchange ActiveSync protocol, as iOS).
 * Mission Control replaces the "All windows" Exposé feature. It gives an overview of all running applications just like "All windows" but groups windows from the same application. At the top of the screen it gives quick access to the Dashboard, Spaces, and running full screen applications.
 * Multi-touch gestures – Similar to iOS, additional gestures performed using a multi-touch input device (e.g. Magic Mouse, Magic Trackpad) will allow the user to scroll, swipe to different pages, and enter Mission Control. While this is not the first official multi-touch support for Mac OS X, it has been expanded; other frameworks, such as Lux, have already created multi-touch support.
 * Multi-User Screen Sharing—The built-in Screen Sharing feature now allows remote users to log into a separate user account from the one that is currently logged in. That means that while one user is logged into a machine, a second user can login to the same machine remotely, seeing their own desktop and user environment.
 * Preview gains several features, including full-screen support and the ability to sign a document just by holding a signed piece of paper up to the camera.
 * QuickTime re-incorporates some features from QuickTime Pro. New features cited include Copy/Paste, Insert Clip, Crop Video, Rotate Video, Resize, Trim, and more Export options.
 * Recovery Partition – Apple has introduced a recovery partition that includes utilities generally found on the OS X discs. This partition will allow the user to restore their computer to its original factory state. It also allows for a new copy of OS X Lion to be installed over the internet.
 * Resume – Applications resume in the same state when re-opened as already seen in iOS.
 * Safari – With full-screen mode and the new WebKit2 Web browser engine.
 * System Information – This feature is a re-design of System Profiler, which has been completely altered with new views which display graphical information on displays, storage devices, memory usage along with other hardware information. The previous layout remains available by clicking "System Report". Early builds of Lion also used System Information as a replacement for "About This Mac", although the final release reinstated the version of this dialog box found in Snow Leopard.
 * Terminal has extra features, including full screen mode.
 * TextEdit gains a new graphical toolbar with font selection and text highlighting. The new TextEdit also supports Apple's new automatic file saving and versions technologies.
 * Versions – Time Machine-like saving and browsing of past versions of documents for applications written to use Versions.
 * Vertical text – Lion supports vertical layouts for East Asian languages.

The complete list from Apple can be found on Apple's website.

Server features

 * Wiki Server 3 – Making it easier to collaborate, share, and exchange information. Users can quickly switch between a server's home page, My Page, Updates, Wikis, People, and Podcasts. File sharing is simpler, and a new Page Editor is added for easy customization.
 * WebDAV File Sharing – Lion Server delivers wireless file sharing for clients that support WebDAV. Enabling WebDAV in Lion Server gives iOS users the ability to access, copy, and share documents on the server from applications such as Keynote, Numbers, and Pages.
 * Profile Manager – Profile Manager delivers simple, profile-based setup and management for Mac OS X Lion, iPhone, iPad, and iPod touch devices. It also integrates with existing directory services and delivers automatic over-the-air profile updates using the Apple Push Notification service.

User interface changes

 * Redesigned Aqua user interface elements, including buttons and progress bars. The red, yellow, and green buttons in the window decorations have also been made smaller.
 * Flexible window resizing from any corner or edge of the window, similar to window resizing in Microsoft Windows and many window managers for X11.
 * The metal finish has also been slightly altered. It is now a lighter shade of gray than before and features a speckled texture.
 * On demand scroll bars now disappear by default when they are not being used, similar to iOS.
 * Scrolling is reversed by default, to act more like a touch screen computer, so that content moves in the direction of finger movement on touch-pad or mouse, rather than the scrollbar moving in the direction of finger movement. Also, like in iOS, scrolling "bounces" when the scroll bar hits the top or bottom of the window.
 * When resizing a window by clicking on the green button (left-top), a transform effect animates the enlargement.
 * New windows fly to the front (like opening an app in iOS).
 * The dashboard is now its own space in Mission Control, rather than in previous versions of OS X where the widgets simply flew in and the background dimmed. The "ripple effect" that was seen previously when adding widgets is no longer there due to this change. Users have the option to return to the old dashboard configuration in System Preferences.
 * Tabs, when selected, now appear as being pushed in and darkened as opposed to previous versions where selected tabs were highlighted in aqua blue.

Dropped features

 * Front Row, a media center application. The application has been copied into Lion by third-party users, however its incompatibility with iTunes 10.4 renders it useless.
 * Rosetta, software which makes possible the execution of PowerPC software on x86 hardware, is no longer available. This disables some programs that ran on previous versions of Mac OS X. Programs requiring Rosetta to operate are not allowed to be distributed via the Mac App Store.
 * Adobe Flash Player and Apple's Java Runtime Environment (JRE) are not included in new installations of Lion, but both can still be downloaded and installed manually. Apple will no longer be actively maintaining its JRE, but Software Update will offer to download Snow Leopard's JRE if a user tries to run a Java program without there being a JRE installed. Programs using Java are not allowed to be distributed via the Mac App Store.
 * iSync, software used for syncing contacts and calendars to third-party mobile phones, is no longer included; however, iSync v3.1.2 from Snow Leopard continues to work.
 * Remote Install Mac OS X, software which allows OS X to be installed using the Remote Disk feature. Using Target Disk Mode, users can circumvent this omission.
 * Apple USB Modem is not compatible with Lion.

Reception
Reception for OS X Lion has generally been positive. In an extensive review of the operating system, Ars Technica recommended Lion. They noted that it feels like it is the start of a new line of operating systems that will continue to be influenced by Apple's iOS platform. The review also compared the introduction of Lion, along with its new conventions that change traditional ways of computing, to the original Mac OS X and when it replaced the classic Mac OS. Macworld called Lion a "radical revision", praising the changes made to the operating system to be more user friendly to new Mac users that are familiar with the iOS interface, while criticizing the limited utility of the interface. Ultimately, the magazine considered Lion an operating system worth getting, giving it 4.5 out of 5 stars. guardian.co.uk called Lion a substantial improvement from its predecessors, and considered it a "steal" given its price. On the other hand, Gizmodo stated that the new interface "feels like a failure" and concluded by saying that "it doesn't feel like a must-have upgrade". Many portable Mac users have also been put off by the lower battery life they have experienced after upgrading to Lion. MacBook Pro users have claimed battery life as low as 2.5 hours after the upgrade to Lion. A temporary fix had been suggested by resetting the System Management Controller (SMC) and switching graphics manually. Apple has now unofficially promised to solve the battery problem, and has reached out to MacBook Pro users at the Official Apple Discussion Forums.

Due to Lion's enhanced security features, including application sandboxing, Dino Dai Zovi, principal of security consultancy Trail of Bits and the coauthor (with Charles Miller) of The Mac Hacker's Handbook, characterized Lion's security as "a significant improvement, and the best way that I've described the level of security in Lion is that it's Windows 7, plus, plus. I generally tell Mac users that if they care about security, they should upgrade to Lion sooner rather than later, and the same goes for Windows users, too."

Software incompatibilities

 * Applications depending on Rosetta, such as Office for Mac 2004 and Quicken, are no longer supported. This affects applications listed as Classic or PowerPC in System Profiler.
 * Unix package managers for Mac OS X such as Fink and MacPorts require reinstalling and then running Xcode.