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9L0-410 OS X champion Essentials 10.7

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9L0-410 exam Dumps Source : OS X champion Essentials 10.7

Test Code : 9L0-410
Test appellation : OS X champion Essentials 10.7
Vendor appellation : Apple
exam questions : 122 actual Questions

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Apple OS X champion Essentials

Apple licensed Technical Coordinator (ACTC) | actual Questions and Pass4sure dumps

linked materials: Books   

This seller-particular Certification is offered by using:Apple ComputerCupertino, CA USAPhone: 408-996-1010Email: This electronic mail tackle is being included from spambots. You exigency JavaScript enabled to view it.

skill level: groundwork                          popularity: energetic

budget friendly: $400 (shortest tune)               

summary:For Mac OS X technical coordinators and entry-level device administrators who've a groundwork in Mac OS X and Mac OS X Server core functionality and an potential to configure key services and role simple troubleshooting of the essential Mac OS X and Mac OS X Server capabilities.

preliminary necessities:You should circulate two tests ($200 each and every). the first exam is Mac OS X assist essentials (passing this examination by myself will deserve you an Apple licensed waiton professional certification aka ACSP). The 2nd examination is Mac OS X Server necessities. practising is purchasable but not required.

carrying on with requirements:None particular

Offline elements:Apple iServices presents instructor led lessons to aid you achieve together.

See replete Apple Certifications

dealer's page for this certification

Mac OS X, Intel trend | actual Questions and Pass4sure dumps

Like this text? They insinuate 

When it comes to Intel Macs, the best circumstance of portability not holds genuine. Apple definitely ships Intel Macs with an Intel-native edition of Mac OS X and considerations sever Mac OS X updates for Intel Macs. which you can view facts by using searching on the build numbers between Mac OS X releases on Intel and vigour computing device Macs. youngsters two Macs might possibly exist operating Mac OS X 10.4.6 with the latest security updates, the build numbers for the OS X free up will issue to exist 8I1119 and 81127, respectively.

This might approach as a shock because Apple has indicated that replete the software that comes bundled with a recent Mac is established (it truly is, it consists of the code vital to race natively on each power laptop and Intel Macs). even though it is genuine for just about replete applications and utilities that ship with Mac OS X (Safari, TextEdit, iTunes, and the different iLife and iWork applications), it isn't bonafide of the entire operating device. There are elements of Mac OS X which are certain to Intel or vitality laptop hardware. most of these data seem enjoy paraphernalia drivers and kernel extensions.

This throws a wrench into the understanding of the usage of a solitary Mac OS X photo as a deployment alternative in a community that includes both Intel and power laptop Macs. basically, at present, Apple has formally brought up that it doesn't aid the introduction of a time-honored Mac OS X version by way of linger clients. however, Apple has likewise indicated that it does draw to finally reintegrate both Intel and vitality laptop adaptations of the working gadget into a solitary release (although unconfirmed, many call that this could ensue in Mac OS X 10.5, a.ok.a. Leopard). however, here's no longer the only incompatibility that exists between Intel and vitality workstation Macs that enjoy an consequence on the potential to create a close photograph that can likewise exist used for deployment to both forms of machines.

complete ebook to Apple Certification and working towards | actual Questions and Pass4sure dumps

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    besides the fact that children I’ve been aiding Macs considering the fact that they got here out in 1984 (when i used to exist in tall college), I haven’t obtained any “formal” practising. It has ordinarily been researching by using doing, reading the occasional booklet and now of direction, TheAppleBlog. Does formal certification really Make a incompatibility as a technician? You inform me.


    recently I bought into an dispute with a supplier that one way or the other notion a technician who first started repairing Macs sixth months in the past trumped my 25 years journey. Did certification Make this adult a stronger technician? Having executed moreorless slightly of hiring myself, I’ve too often create that certification most effective verifies your capability to recall a test and might now not enjoy presence within the actual world.

    Now that the market has modified and everyone seems to exist competing for scarce components, possibly a certification would exist an further aspect? What’s the company approach for unbiased Mac technicians looking greater? The reply took loads of research — even Apple wasn’t in a position to reply my questions — so study from my experience.

    credit score goes to each Brian best of BestMacs and Doug Hanley of MacTEK practicing, because without them I wouldn’t bethink the alphabet soup of ACSP, ACMT, ACTC, ACSA, AASP, ACN and more. Didn’t replete of us develop into Mac users to linger away from mysterious phrases? As lots of you understand, the profit of the Apple consumer interface is equalled handiest by means of the frustration of trying to exist mindful Apple’s certifications courses. figuring out this direction was an abominable lot harder than any video video game I’ve ever performed, however a “game” may well exist the optimum metaphor to accountfor the system.

    The game

    You start the “online game” as a common Mac consumer. The three worlds you’ll frequently view in the online game are IT, seasoned Apps, and revenue. As an IT grownup might exist you enjoy got advantage, might exist you don’t. Nothing stops you from effectively repairing Macs on your own, until you attain things that principally void the warranty and you Get caught doing so. You will not enjoy consent per se from Apple to drudgery on Macs. Many folks are ecstatic at this plane accumulating cash separately, but which you could’t proceed any extra until you Get a certification — the key that unlocks the next stage in the online game.

    the first certification most scramble for is Apple certified waiton professional (ACSP) which was once called an Apple certified assist Desk professional (ACHDS). This certifies your potential to stand in mind the operating paraphernalia and is earned in line with the OS edition. therefore, you are an Apple certified waiton skilled in 10.5 (or quickly 10.6). every OS requires certification, but your certification does not expire. for this reason, if you are a ACHDS in 10.three, you could appellation your self licensed with out realizing 10.5 at all. Your can recall the check without working towards (many do), self-analyze by way of materials from Peachpit, or attend an instructor-lead course at an Apple approved working towards middle (AATC). MacTek is a kindly of centers. You’ll recall the check at a Prometric testing center and pay round $200. The verify takes about 90 minutes or so and you Get the effects automatically.

    Apple Consultants network

    whereas certification is the capability, the conclusion you could exist reaching for is the skill to exist portion of the Apple Consultants network (ACN). becoming a member of the ACN requires any Apple certification, such as the ACSP mentioned above, or any variety of other certifications (described under, though one source says now not replete certifications are valid, so watch out). retaining with the video video game analogy, the ACN is enjoy a whole recent belt of the video online game you want to discover, but the boss that enjoy to exist defeated first is Apple, and your weapon is a certification!

    After getting a certification you can then practice to exist a portion of the ACN. The application payment is $60 and the precise payment to combine is $395 as a sole proprietor. the entire requirements are right here. You’ll Get a lot of merits corresponding to product discounts as smartly as the faculty to community with other Macintosh consultants. As an ACN, Apple withhold employees may additionally hand out your card to clients within the shop. Now your enterprise can in fact extend as each Apple store client is a potential customer for you.

    ACN membership is excellent and a lot of live at this stage of the “game” the usage of the ACN membership as a multiplier for their revenue. youngsters, you nonetheless can’t attain hardware repairs under assurance nor order Apple parts. As with the video video game, you’re stuck at this stage unless you explore further and recall a peek at to subjugate the subsequent boss. Apple always controls the guidelines. accept it as a portion of the video game. Fail to accept it and likewise you’ll Get slapped lower back to the starting of the video game sooner than that you could click on the home button.

    Server Administration Certification

    From this point, you've got a pair instructions that you may go. that you would exist able to focal point on restore and service, or you can focus on server or superior application administration (many individuals will attain both). i will talk about the server administration certifications and the hardware features certifications. that you may suppose of each and every of these as two sever worlds within the game. that you can select one or the other, or learn them both.

    the first stage server administration certification is one other four-letter acronym: ACTC: Apple licensed Technical Coordinator. apart from passing the examine for ACSP, you’ll physiognomy the Server essentials test. This extends your notebook expertise to servers. an excellent greater degree of certification in the server realm is an ACSA — Apple certified techniques Administrator. For the ACSA, you’ll deserve to stream 4 tests: Server essentials, directory features, Deployment, and Mobility and security for 10.6 (or superior device Administration for 10.5).

    Apple likewise offers the ACMA (Apple licensed Media Administrator) which contains Server necessities, Xsan, final reduce Server and as an alternative, assist necessities, Deployment, directory functions, or last gash degree 1. other certifications aren't necessarily IT linked and are software-concentrated. That’s a realm I’m no longer exploring as they chose the IT track at the beginning of the online game.

    Hardware fix Certification

    relocating on from server administration to exact Apple hardware fix, the basic certification you are going to deserve is the Apple licensed Macintosh Technician (ACMT), formerly the Apple licensed moveable Technician (ACPT) and Apple certified computing device Technician (ACDT). This certification capability you are theoretically certified to attain assurance repairs on Apple Macintosh device. The expertise required for ACMT are those of hardware repair and utility troubleshooting. You don’t exigency an ACSP to exist an ACMT, however many people deserve each. The tutorial manner for hardware repair is greater immoderate and it’s less probably you’ll stream the examine with out some practicing. At this degree, that you may additionally scramble to an AATC and pay about $four,800 for both the hardware and utility features of the path, or your should buy self-study materials from Apple known as “Apple trust Technician practicing” for $299.

    Apple licensed service provider

    similar to how passing the ACSP means that you can combine the Apple Consultants network, passing the ACMT allows you to enter the realm of an Apple authorized carrier provider (AASP). You may additionally now not immediately become one though, and only AASP’s Get compensation from Apple for warranty work. youngsters, being an ACMT is terribly helpful in case you wish to Get a job as an AASP. You might likewise additionally practice to attain warranty repairs on your larger corporation of over 50 Macs via the Self-service software. in case you wish to enhance to being in a position to attain warranty repairs for any one, you’ll physiognomy that equal boss once again, Apple. note that becoming an ACMT will now not always deserve you from now on cash than an ACSA or ACTC. facing the subsequent boss may well exist too costly and too restricting, but when you attain wish the subsequent degree, examine on.

    getting to that AASP plane is in reality the ultimate stage of the video game. You’ll should enjoy an ACMT on staff and comply with stricter requirements than joining the Apple Consultants network. often you’ll exigency a actual store front and not exist a one-grownup operation. Apple provides exceptions (doesn’t every video game enjoy cheat codes?), however don’t matter number on it. after getting your AASP you can exist listed with Apple as a provider company and Get reimbursed for warranty repairs.

    So I’ve loaded the online game and pressed delivery. Is certification value it? What about ACN or AASP? Which practicing may noiseless i scramble for? Is teacher lead practicing price it? Any working towards vendors willing to sponsor me? What concerning the self-look at classes? share with me your experiences within the online game and let’s ameliorate a definitive lead together with “cheat codes.”

    Apple-authorized agencies

    ACN (Apple Consultants network)What it is: community on Apple gurus, receives discounts and assistance from Apple, and can exist referred from Apple retail outlets.requirements: Any certification.

    AASP (Apple licensed provider company)what is it: company it truly is permitted to attain Apple assurance repairs for compensation and order parts from Apple.necessities: enjoy an Apple licensed Macintosh Technician on team of workers, among other requirements.


    Apple certified aid professional: primary knowing of the client Mac operating system and troubleshooting.

    Apple licensed Technical Coordinator: Deeper knowing of the Mac OS, including the Mac OS X Server and Server essentials.

    Apple certified techniques Administrator: Even more suitable technical understanding of the Mac OS X Server, including passing exams on Server necessities, listing features, Deployment, and Mobility and safety.

    Apple licensed Media Administrator: here's a sister track of the “Apple licensed techniques Administrator” with a spotlight on the needs of media administration, and comprises working towards in XSan or final reduce.

    Apple certified Macintosh Technician: that you could attain Apple hardware repairs, both in and out of guarantee. Required to birth (or Get a job with) an Apple licensed carrier provider, or self-provider your huge organization.

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    OS X champion Essentials 10.7

    Pass 4 certain 9L0-410 dumps | 9L0-410 actual questions |

    Mozilla will retire Firefox champion for OS X 10.6, 10.7, and 10.8 in August 2016 | actual questions and Pass4sure dumps

    Mozilla today announced that it will linger Firefox champion for OS X 10.6 Snow Leopard, OS X 10.7 Lion, and OS X 10.8 Mountain Lion in August 2016. Unlike Google, which likewise dropped Windows XP and Vista support, Mozilla seems to exist sticking to only removing champion for conventional Macs.

    This means Mozilla will provide regular Firefox updates and security patches for Mac users on these operating systems for four more months. After that, the browser will noiseless work, but it will exist stuck on the last version released in August.

    Mozilla likewise offers a Firefox version called Extended champion Release (ESR) for schools, universities, businesses, and others who exigency waiton with mass deployments. Firefox ESR releases are maintained for one year, and so Mozilla will continue to champion it on OS X 10.6, 10.7, and 10.8 “until mid-2017.” Firefox ESR 45 will exist the last version that supports these conventional OS X versions.

    Mozilla correctly notes that “all three of these versions are no longer supported by Apple” and that “unsupported operating systems receive no security updates, enjoy known exploits, and are uncertain for you to use.” If you want to continue getting Firefox updates, the company thus recommends upgrading your Mac.

    It’s luckless that Mozilla is not doing the selfsame with conventional Windows versions. withhold in mind that Microsoft retired Mainstream champion for Windows XP on April 14, 2009 and then pulled Extended champion for the operating system on April 8, 2014. Mozilla is thus going out of its way to champion XP for additional years, even longer than Microsoft.

    Windows XP users cannot upgrade to newer versions of Microsoft’s browser: IE8 is the latest version they can install. IE9 is only available for Windows Vista and Windows 7, while IE10 and IE11 are only for Windows 7 and Windows 8. Many XP users thus pick to exhaust third-party browsers.

    With Chrome no longer an option, many are likely going with Firefox.

    Last month, XP noiseless had about 11 percent market share, according to Net Applications. Vista had 1.41 percent market share, and the three conventional OS X versions had a combined 0.83 percent.

    So if you’re wondering why exactly Mozilla keeps supporting Firefox on Windows XP and Vista, the numbers narrate the actual story. There are hundreds of millions using the browser on the ancient operating systems, and Mozilla would rather enjoy those users than lose them.

    But enjoy Google before it, Mozilla is not helping these users by not encouraging them to upgrade. Even with an up-to-date browser, using Windows XP and Vista is simply a indigent security choice.

    Inside Mac OS X 10.7 Lion: Font bespeak 3, Emoji champion | actual questions and Pass4sure dumps

      Apple has enhanced its Font bespeak app for managing installed font faces, and has added a recent Emoji font commonly used in chat to express ideograms.Font bespeak 3.0 now provides more flexible displays of the character glyphs supplied by a particular font face, with the gauge alphabetical list augmented with a array of every glyph used in the font, and an information panel that lists its replete metadata.

    The information panel (below) presents every supported language, the version, its installed location, a description of the font, its copyright and trademark data, the number of glyphs supplied, whether it is embeddable, enabled, copy protected or installed as a duplicate.

    Duplicate font files are flagged with a warning icon, and can exist fixed automatically or resolved manually from a comparison drop down sheet (below).

    The recent Apple Color Emoji font supplies 502 glyphs in a TrueType font. Apple previously added emoticon champion in iOS within Japanese input, which replaced typed characters with suggested faces created from Roman characters. The recent scramble in Lion suggests company is likely to add actual Emoji input to the iOS as well.

    Mac OS X 10.7 Lion: the Ars Technica review | actual questions and Pass4sure dumps

    Mac OS X 10.7 Lion: the Ars Technica review reader comments 401 with 262 posters participating, including chronicle author Share this story
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  • Mac OS X 10.7 was first shown to the public in October 2010. The presentation was understated, especially compared to the bold rhetoric that accompanied the launches of the iPhone ("Apple reinvents the phone") and the iPad ("a magical and revolutionary device at an unbelievable price"). Instead, Steve Jobs simply called the recent operating system "a sneak peek at where we're going with Mac OS X."

    Behind Jobs, the screen listed the seven previous major releases of Mac OS X: Cheetah, Puma, Jaguar, Panther, Tiger, Leopard, and Snow Leopard. Such brief retrospectives are de rigueur at major Mac OS X announcements, but long-time Apple watchers might enjoy felt a slight tingle this time. The public "big cat" branding for Mac OS X only began with Jaguar; code names for the two earlier versions were not well known outside the developer community and were certainly not portion of Apple's official marketing message for those releases. Why bring the cat theme back to the forefront now?

    Want an eBook or PDF copy? champion Ars and it's yours.

    The reply came on the next slide. The next major release of Mac OS X would exist called Lion. Jobs didn't Make a expansive deal out of it; Lion's just another expansive cat name, right? Within seconds, they were on to the next slide, where Jobs was pitching the recent release's message: not "king of the jungle" or "the biggest expansive cat," but the "back to the Mac" theme underlying the entire event. Mac OS X had spawned iOS, and now Apple was bringing innovations from its mobile operating system back to Mac OS X.

    Apple had Good judgement to coy away from presenting Lion as the pinnacle that its appellation implies. The last two major releases of Mac OS X were both profoundly shaped by the meteoric climb of their younger sibling, iOS.

    Steve Jobs presents the first seven releases of Mac OS X in a slightly unusual formatSteve Jobs presents the first seven releases of Mac OS X in a slightly unusual format

    Leopard arrived later than expected, and in the selfsame year that the iPhone was introduced. Its successor, Snow Leopard, famously arrived with Your browser does not champion the audio element. Click here to listen

    no recent features , concentrating instead on internal enhancements and bug fixes. Despite believable official explanations, it was hard to shudder the feeling that Apple's burgeoning mobile platform was stealing resources—not to mention the spotlight—from the Mac.

    In this context, the appellation Lion starts to recall on darker connotations. At the very least, it seems enjoy the linger of the expansive cat branding—after all, where can you scramble after Lion? Is this process of taking the best from iOS and bringing it back to the Mac platform just the first facet of a complete assimilation? Is Lion the linger of the line for Mac OS X itself?

    Let's achieve aside the pessimistic prognostication for now and deem Lion as a product, not a portent. Apple pegs Lion at 250+ recent features, which doesn't quite match the 300 touted for Leopard, but I guess it replete depends on what you deem a "feature" (and what that "+" is supposititious to mean). Still, this is the most significant release of Mac OS X in many years—perhaps the most significant release ever. Though the number of recent APIs introduced in Lion may plunge short of the landmark Tiger and Leopard releases, the most famous changes in Lion are radical accelerations of past trends. Apple appears tired of dragging people kicking and screaming into the future; with Lion, it has simply decided to leave without us.

    Table of Contents
  • Installation
  • Reconsidering fundamentals
  • Lion's recent look
  • Scroll bars
  • Window resizing
  • Animation
  • Here's to the crazy ones
  • Window management
  • Application management
  • Document model
  • Process model
  • The pitch
  • The reality
  • Internals
  • Security
  • Sandboxing
  • Privilege separation
  • Automatic Reference Counting
  • Enter (and exit) garbage collection
  • Cocoa reminiscence management
  • Enter ARC
  • ARC versus garbage collection
  • ARC versus the world
  • The state of the file system
  • What's wrong with HFS+
  • File system changes in Lion
  • File system future
  • Document revisions
  • Resolution independence
  • Applications
  • The Finder
  • Mail
  • Safari
  • Grab bag
  • System Preferences
  • Auto-correction
  • Mobile Time Machine
  • Lock screen
  • Emoji
  • Terminal
  • About This Mac
  • Recommendations
  • Conclusion
  • A brief note on branding: on Apple's website and in some—but not all—marketing materials, Apple refers to its recent Mac operating system as "OS X Lion." This may well whirl out to exist the appellation going forward, but given the current state of confusion and my own stubborn nostalgia, I'm going to summon it "Mac OS X" throughout this review. Indulge me.


    Lion's system requirements don't disagree much from Snow Leopard's. You noiseless exigency an Intel-based Mac, though this time it must likewise exist 64-bit. The last 32-bit Intel Mac was discontinued in August of 2007; Apple chose a similar four-year cut-off for dropping PowerPC support, with minimal customer backlash. Time marches on.

    But sometimes time marches on a bit too fast. Though this is the second version of Mac OS X that doesn't champion PowerPC processors, this is the first version that won't race PowerPC applications. In Snow Leopard, the Rosetta translation engine allowed PowerPC applications to run, and race well, often faster than they ran on the (admittedly older) PowerPC Macs for which they were developed. Lion no longer includes Rosetta, even as an optional install.

    No one expects eternal champion for PowerPC software, and any developer that doesn't yet enjoy Intel-native versions of replete its applications is clearly not particularly dedicated to the Mac platform. Nevertheless, people noiseless depend on some PowerPC applications. For example, I enjoy an conventional PowerPC version of Photoshop. Though Photoshop has long since gone Intel-native, it's an expensive upgrade for someone enjoy me who uses the program only rarely. The PowerPC version suits my needs just fine, but it won't race at replete in Lion.

    Another common sample is Quicken 2007, noiseless the most capable Mac version of Intuit's finance software, and noiseless PowerPC-only. This is clearly Intuit's fault, not Apple's, but from a regular user's perspective, it's hard to understand why Apple would remove an existing, completed feature that helped so many people.

    In reality, every feature has some associated maintenance cost. This is perhaps even more genuine of a binary translation framework that may enjoy abysmal hooks into the operating system. I'm willing to give Apple the profit of the doubt and assume that disentangling PowerPC-related code from the operating system once and for replete was famous enough to warrant the customer inconvenience. But it noiseless stings a little.

    The future shock continues with the purchase and installation process. Lion is the first version of Mac OS X to exist distributed through Apple's recently introduced Mac App Store. In fact, the Mac App Store is the only situation where you can buy Lion.

    Apple's conclusion last year to sell its iLife and iWork applications through the Mac App Store was not unexpected, but the presence of Apple's professional photography application, Aperture, caught some people off guard—as did its greatly reduced price ($80 vs. $200 for the boxed version).

    The developer preview releases of Lion were likewise distributed through the Mac App Store. Apple's developer releases enjoy been distributed digitally for many years now, but the switch from downloading disk images from Apple's developer website to "redeeming" promo codes and downloading recent builds from the Mac App Store raised some eyebrows. When Apple announced that its recent Final gash Pro X professional video editing application would—you guessed it—be distributed through the Mac App Store, and at a greatly reduced price, even the most dense Apple watchers started to Get the hint.

    The Lion installer application iconThe Lion installer application icon

    And so they enjoy Lion, priced at a mere $29 (the selfsame as its "no recent features" predecessor), available exclusively through the Mac App Store. It's an audacious move, yes, but not unexpected.

    Apple is so done with stamping bits onto plastic discs, putting the discs into cardboard boxes, putting those boxes onto trucks, planes, and boats, and shipping them replete over the world to retail stores or to mail-order resellers who will eventually achieve those selfsame boxes onto a different set of trucks, trains, and planes for final delivery to customers, who will then remove the disc, fling away the cardboard, and instruct their computers to extract the bits. No, from here on out, it's digital distribution replete the way. (This, I suppose, marks the linger of my longstanding tradition of showing the product boxes or optical discs that Mac OS X ships on. Instead, you can view the installer application icon on the right.)

    Lion is a big download and fleet network connections are noiseless not ubiquitous. But recent Macs will approach with Lion, so the most material question is, how many people who draw to upgrade an existing Mac to Lion don't enjoy a fleet network connection? The class of people who perform OS upgrades probably has a higher penetration of high-speed Internet access than the general population. I likewise suspect that Apple retail stores may exist willing to waiton out customers who just can't manage to download a 3.76GB installer in a reasonable amount of time.

    [Update: Macworld reports that there will, in fact, exist a physical manifestation of Lion. Starting in August, Apple will sell Lion on a USB stick for $69. Apple has likewise said that customers are welcome to bring their Macs to Apple retail stores for waiton buying and installing Lion.]

    In the meantime, if you're reading this, chances are Good that you enjoy a fleet broadband connection; feel free to desist reading right now, launch the Mac App Store, and start your multi-gigabyte download before continuing. What you'll exist rewarded with at the linger is an icon in your Applications folder labeled "Install Mac OS X Lion." (See?)

    Once you enjoy the installer application, you could (were you so inclined) dig into it (control-click, then demonstrate Package Contents) and find the meaty center, a 3.74GB disk image (InstallESD.dmg, stored in the Contents/SharedSupport folder). You could then exhaust that disk image to, say, singe a Lion installation DVD or create an emergency external boot disk.

    I doubt any of these things are officially supported by Apple, but the point is that there's nothing exotic about the Lion installer. enjoy replete past versions of Mac OS X, Lion has no serial number, no product activation, and no DRM of any kind. In fact, the Mac App Store's licensing policy is even more permissive than past releases of Mac OS X. Here's an excerpt from Lion's license agreement:

    If you obtained a license for the Apple Software from the Mac App Store, then matter to the terms and conditions of this License and as permitted by the Mac App Store Usage Rules set forth in the App Store Terms and Conditions ( ("Usage Rules"), you are granted a limited, non-transferable, non-exclusive license:

    (i) to download, install, exhaust and race for personal, non-commercial use, one (1) copy of the Apple Software directly on each Apple-branded computer running Mac OS X Snow Leopard or Mac OS X Snow Leopard Server ("Mac Computer") that you own or control;

    The references to Snow Leopard are a bit confusing, but withhold in mind that you exigency Snow Leopard to purchase and download Lion for the first time. I suspect the license agreement will exist updated once Lion has been out for a while.

    There's likewise another appealing clause in the license, from that selfsame section:

    (iii) to install, exhaust and race up to two (2) additional copies or instances of the Apple Software within virtual operating system environments on each Mac Computer you own or control that is already running the Apple Software.

    Putting it replete together, Apple says you're allowed to race up to three copies of Lion—one real, two inside virtual machines—on every Mac that you own, replete for the low, low price of $29. Not a infamous deal.

    The installer itself is deceased simple, foreshadowing the pervasive simplification in Apple's recent OS. There are no optional installs and no customization. The only response the user provides is agreeing to the obligatory EULA, and the only configurable install parameter is the target disk.


    But wait a second—how exactly is this going to work? Surely an entirely recent operating system can't exist installed on top of the currently running operating system by an application stored on the selfsame volume. Without a plastic disc to boot from, how is it even feasible to upgrade a standalone Mac with just one hard drive?

    These questions probably won't occur to an middling consumer, which is sort of the point, I guess. certain enough, if you just nigh your eyes, launch the installer application, and click your way through the handful of screens it presents, your Mac will reboot into what looks enjoy the gauge Mac OS X installer application from years past. When it's done, your Mac will reboot into Lion. Magic!

    Okay, it's not magic, but it is a bit complicated. The first and most lasting amaze is that the Lion installer will actually repartition the disk, carving out a 650MB slice of the disk for its own use.

    Don't worry, replete existing data on the disk will exist preserved. (Mac OS X has had the faculty to add partitions to existing disks without destroying any data for many years now.) replete that's required is enough free space to reshuffle the data as needed to Make leeway for the recent partition.

    Here's an sample from my testing. I started with a solitary 250GB hard drive split into two equal partitions: the first named "Lion Ex," currently running Snow Leopard, and the intended target of the Lion install, and the second named "Timex," the Time Machine backup volume for Lion Ex. The output from the diskutil list command appears below.

    /dev/disk1 #: kind appellation SIZE IDENTIFIER 0: GUID_partition_scheme *250.1 GB disk1 1: EFI 209.7 MB disk1s1 2: Apple_HFS Lion Ex 125.0 GB disk1s2 3: Apple_HFS Timex 124.6 GB disk1s3

    Now here's that selfsame disk after installing Lion, with the recent partition highlighted:

    /dev/disk1 #: kind appellation SIZE IDENTIFIER 0: GUID_partition_scheme *250.1 GB disk1 1: EFI 209.7 MB disk1s1 2: Apple_HFS Lion Ex 124.5 GB disk1s2 3: Apple_Boot Recovery HD 654.6 MB disk1s3 4: Apple_HFS Timex 124.6 GB disk1s4

    The recent partition is actually considered a different type: Apple_Boot. The Recovery HD volume won't exist automatically mounted upon boot and therefore won't issue in the Finder. It's not even visible in the Disk Utility application, appearing only as a tiny blank space in the partition map for the disk. But as shown above, the command-line diskutil program can view it. Diskutil can mount it too.

    Doing so reveals the partition as a established HFS+ volume. The top plane contains a directory named which in whirl contains a few wee files related to booting along with an invisible 430MB internally compressed disk image file named BaseSystem.dmg. Mount that disk image and you find a 1.52GB bootable Mac OS X volume containing Safari, most of the contents of the gauge /Applications/Utilities folder (Disk Utility, Startup Disk, Terminal, etc.), plus a Mac OS X Lion installer application. In other words, it looks a lot enjoy a gauge Mac OS X installer DVD.

    A subset of the files copied to the recovery partition is likewise copied to the installation target disk by the installer and blessed as the recent bootable system. This is what the Lion installer reboots into. The files to install will exist read from the Lion installer application downloaded earlier from the Mac App Store. After the installation is complete, the temporary boot files are removed, but the Recovery HD partition remains on the disk. Hold down ⌘R during system startup to automatically boot into the Recovery HD partition. (Holding down the option key during startup—not a recent feature in Lion—will likewise demonstrate the Recovery HD partition as one of the boot volume choices.)

    Booting from the recovery partition really means mounting and then booting from the BaseSystem.dmg disk image on the recovery partition. Doing so presents a list of the traditional Mac OS X install disc options, including restoring from a Time Machine backup, reinstalling Mac OS X, running Disk Utility, resetting your password, and so on. There's likewise an option to Get waiton online, which will launch Safari. Including Safari on the recovery partition is a nice touch, since most people's first desist when diagnosing a problem is Google, not the Genius Bar.

    The upshot is that after replete the file compression magic added in Snow Leopard to reduce the footprint of the OS, Lion steals over half a gigabyte of your disk space as portion of its installation process, and never gives it back. The partition's appellation makes Apple's intent clear: it's meant as a last-ditch mechanism to diagnose and repair a Mac with a hosed boot volume. (Hosed, that is, in the software sense; existing as it does on the boot disk itself, the recovery partition won't exist much exhaust if the disk has hardware problems.)

    Apparently Apple has decided that the faculty to boot a Mac into a known-good (software) state is well worth sacrificing a wee amount of disk space. MacBook Air owners or other Mac users with diminutive solid-state disk drives may disagree, however. In that case, the disk space can exist reclaimed by some judicious repartitioning with Disk Utility (or the diskutil command-line tool) while booted from another disk. But don't exist surprised when the fellow at the Genius Bar frowns a dinky at your aberration from the Apple Way.

    Reconsidering fundamentals

    The user-visible changes in Lion are legion. You'll exist hard-pressed to find any portion of the user interface that remains completely unchanged from Snow Leopard, from the peek and feel replete the way down to basic behaviors enjoy application and document management. In Lion, Apple has taken a hard peek at the assumptions underlying the last ten years of Mac OS X's development—and has decided that a lot of them exigency to change. Get ready.

    Lion's recent look

    Let's ease into things with a tour of Lion's revised user interface graphics. Though Apple noiseless uses the appellation "Aqua" to advert to Lion's interface, the peek is a far weep from the lickable, candy-coated appearance that launched the brand. If you can imagine three dials labeled "color," "contrast," and "contour," Apple has been turning them down slowly for years. Lion accelerates that process.

    The shapes enjoy started to change, too. The traditional capsule shape of the gauge button has given way to a squared-off, Chiclets-style appearance. The tubular shape of the progress bars, a fixture since even before the dawn of Mac OS X, has been replaced with a vaguely puffy stripe of material. Radio buttons, checkboxes, slider thumbs, segmented controls, "tab" controls—nearly everything that used to protrude from the screen now looks as if it was pounded down with a rubber hammer.

    Finder sidebar: grayFinder sidebar: gray

    Even the elements that peek identical, enjoy the unpretentious gray window title bars, are slightly different from their Snow Leopard counterparts. The recent peek is not a radical departure—everything hasn't gone jet black and grown fur, for example—but this is the first time that nearly every ingredient of the gauge GUI has been changed in a way that's identifiable without a color meter or a magnifying glass.

    For the most part, the recent peek speaks in a softer voice than its predecessor. The total removal of blue highlights from several controls (e.g., pop-up menus, combo boxes, slider thumbs, and tab controls) makes most interfaces issue slightly less garish. On the other hand, the additional green in the blue highlights that noiseless attain exist makes those controls issue more saccharine.

    Apple says that its goal with the Lion user interface was to highlight content by de-emphasizing the surrounding user interface elements. You can view this most clearly in sidebar and toolbar icons, which are now monochromatic in most of the famous bundled applications. But this has the luckless side consequence of making interface elements less distinguishable from each other, especially at the wee sizes typical in sidebars. I'm not certain the "increased emphasis on content" is enough to poise out the loss, especially in applications enjoy the Finder.

    LionLion Snow LeopardSnow Leopard

    Appearance changes can enjoy effects beyond emphasis, fashion, and mood. recall the "traffic light" red, yellow, and green window widgets, for example. As you can view in the images on the right, they've gotten smaller in Lion. Or rather, the colored portion has gotten smaller; the actual clickable belt has lost only one pixel in height and five pixels in total width across replete three widgets.

    But the psychological consequence of the shrunken appearance is something else entirely. Despite the tiny incompatibility in the functional size, I find myself being ever-so-slightly more observant when targeting these widgets in Lion. It's a dinky annoying, especially since it's not lucid to me how the new, smaller size fits into Lion's recent look. Does such a wee reduction in size really serve to better emphasize window content? After all, None of the other controls enjoy gotten any smaller.

    Other aspects of the recent peek enjoy clearer intentions. The flatter, more matte peek of most controls, and especially the squared-off shape of the gauge button, replete bring to mind the peek of Apple's other operating system, iOS. One control in particular takes the iOS connection even further.

    Finally, there's Apple's budding enjoy lookout with a particular linen texture. It made its first appearance on the backside of some Dashboard widgets. More recently, it was used as the background pattern for the notifications sheet in iOS 5. In Lion, it's featured even more prominently as the background for the newly restyled login screen, now featuring circular frames for user icons. (Also note the subset of menu bar status icons noiseless visible in the top-right corner of the screen.)

    Linen for your login screen Enlarge / Linen for your login screen Scroll bars

    Scroll bars, which Apple likes to summon "scrollers" these days, are among the least-changed interface elements in Mac OS X. While the comfort of the Aqua interface was refined—edges sharpened, pinstripes removed, shines flattened—scrollbars stubbornly retained their original Aqua peek for over a decade.

    A scroll bar from Mac OS X DP3, released in 2000A scroll bar from Mac OS X DP3, released in 2000 A scroll bar from Mac OS X 10.6, released in 2009A scroll bar from Mac OS X 10.6, released in 2009

    Scroll bars haven't been entirely static in Mac OS X, however. For many years, iTunes has had its own custom scroll bar look.

    A scroll bar from iTunes 10.2.2, released in 2011A scroll bar from iTunes 10.2.2, released in 2011

    When these recent scroll bars were first introduced in iTunes 7 in 2006, there was some speculation that this was a tribulation race for a recent peek that would soon spread throughout the OS. That didn't happen. But now, five years later, scroll bars are finally changing system-wide in Mac OS X. Here's a scroll bar from Lion:

    A scroll bar from Mac OS X 10.7 LionA scroll bar from Mac OS X 10.7 Lion

    The smeared gradient and fuzzy edges of the iTunes scroll thumb are nowhere to exist seen. Instead, they enjoy a narrow, monochrome, sharp-edged lozenge. Just enjoy the window widgets, the scroll thumb appears slightly smaller than its Snow Leopard counterpart. (In this case, total scroll bar width and the clickable belt are actually the selfsame as in Snow Leopard.)

    The change in appearance might distract you from what's really different: where are the scroll arrows? You know, the dinky buttons on either linger of the scroll bar (or grouped together on one end) that you click to scramble the scroll thumb a bit at a time? Well, they're gone.

    But wait, there's more. Here's a Finder window.

    The complete contents of Lion's Applications folder…or is it?The complete contents of Lion's Applications folder…or is it?

    Though I can assure you that Lion comes with more than eight applications, you wouldn't know it from looking at this screenshot. Forget about the arrows, where are the scroll bars?

    Placing the cursor into the window and using the scroll wheel on the mouse or two-finger scrolling on a trackpad reveals what you might enjoy already guessed based on the shape and appearance of the recent scroll thumbs. Extremely thin, monochrome scroll thumbs fade in as the scrolling begins, and evaporate shortly after it ends. These momentary scroll thumbs issue on top of the window's content, not in alleys reserved for them on the edges of the window.

    Initiating scrolling (via mouse wheel or trackpad) reveals overlay scroll bars. More applications below!Initiating scrolling (via mouse wheel or trackpad) reveals overlay scroll bars. More applications below! An iOS scroll barAn iOS scroll bar

    These ghostly overlay scroll bars are straight out of iOS. When they were introduced in 2007 on the iPhone's 3.5-inch screen, they made perfect sense. Dedicating one or more finger-width strips of the screen for always-visible, touch-draggable scroll bars would enjoy been a colossal consume of pixels (and anything less than a finger's width of pixels would enjoy been too narrow to comfortably use). Overlay scroll bars were essential in iOS, and completely in keeping with its direct manipulation theme. In iOS, you don't exploit an on-screen control to scroll, you simply grab the whole screen with your finger and scramble it.

    Apple isn't (yet) asking us to start poking their fingers at their Mac's screen, but it does now ship every Mac with some kindly of touch-based input device: internal trackpads on laptops, and external trackpads or touch-sensitive mice on desktops. Lion further cements the dominance of palpate by making replete touch-based scrolling drudgery enjoy it does on a touchscreen. Touching your finger to a control surface and affecting it downwards will scramble the document downwards, revealing more content at top and hiding some of the content that was previously visible on the bottom. This sounds perfectly logical, but it likewise happens to exist exactly the opposite how scrolling has traditionally worked with mouse scroll wheels. The consequence is extremely disconcerting, as their fingers unconsciously flick at the scroll-wheel while their eyes view the document affecting the "wrong" way.

    Scroll direction setting in the Mouse preference pane. Checked means the recent
 Lion scrolling direction is in effect.Scroll direction setting in the Mouse preference pane. Checked means the recent Lion scrolling direction is in effect.

    Thankfully, there is a preference to restore the conventional mapping of finger movement to scroll direction. There's a second setting in the Trackpad preference pane, phrased in the opposite way. Unfortunately, the settings are linked; you can't enjoy different values for each kindly of input device.

    Though the unification of scrolling gestures is logical, it's difficult to Get used to after so many years of doing things the other way. The most common scrolling direction is downwards, and the most natural finger movement is curling inwards. These two things align when using a mouse wheel with the "old" scrolling direction setting. conventional habits aside, it may exist that the incompatibility between touching a screen directly and touching a sever device on a horizontal surface in front of the screen is just too much to warrant a solitary input vocabulary.

    Either way, there's certain to exist an uncomfortable transition era for everyone. For example, the two-finger swipe to the left or right used to switch between screens in Launchpad (described later) feels "backwards" when the scroll direction preference is set to the traditional, pre-Lion behavior. Perhaps just seeing a screen covered with a grid of icons unconsciously triggers the "iOS expectations" region of their brains. (And if you set the scroll direction to "feel right" for two-finger swiping in Launchpad, then the four-finger swipe between Spaces feels backwards! Sigh.)

    Scroll bars attain more than just let us scroll. First, their state tells us whether there's anything more to see. A window with "inactive" (usually shown as dimmed) scroll bars indicates that there is no content beyond what is currently visible in the window. Second, when a document has more content than can fortunate in a window, the scroll bars narrate us their current position within that document. Finally, the size of the scroll thumb itself—or the amount of leeway the scroll thumb has to scramble within the scroll bar, if you want to peek at it that way—gives some hint about the total size of the content.

    Classic Mac scroll barsClassic Mac scroll bars

    Most computer users aren't conscious of such subtleties, but their combined effects are profound. Long-time Mac users might bethink a time when scroll thumbs were perfectly square regardless of the total size of a window's content. When I think back to my time using those scroll bars, I don't recall any problems. But just try using these so-called "non-proportional" scroll bars today. The modern computer user's mind revolts at the lack of information, usually treating it instead as delusive information about the total size of a window's content. ("This window looked enjoy it had pages and pages of content, but when I dragged the tiny square scroll thumb replete the way from the top to the bottom, it only revealed two recent lines of text!") Only when this cue is gone attain you realize how much you've been relying on it.

    And withhold in mind that proportional scroll thumbs are the most subtle of the cues that scroll bars provide. The others are even more widely relied upon. The complete lack of visible scroll bars leaves a huge information void.

    Let's achieve aside the close for a moment. In the absence of scroll bars, are there other visual cues that could provide the selfsame information? Well, if truncated content appears at the edge of a window, it's usually a safe wager that there's more content in that direction. The prevalence of whitespace (between icons in the Finder, between lines of text, etc.) can Make such truncation less obvious or even undetectable, but at least it's something. For total content size and position within the document, there's no alternative even that good.

    But panic not, gentle scroller. enjoy the scroll direction, scroll bar visibility has a dedicated preference (in the general preference pane):

    Scroll bar settings in the general preference paneScroll bar settings in the general preference pane

    The default setting, "Automatically based on input type," will exhaust overlay scroll bars as long as there's at least one touch-capable input device attached (though the trackpad on laptops doesn't matter if any other external pointing devices are connected). If you don't enjoy this kindly of second-guessing, just pick one of the other options. The "When scrolling" option means always exhaust overlay scroll bars, and the "Always" option means always demonstrate scroll bars, using the appearance shown earlier.

    Lion includes recent APIs for briefly "flashing" the overlay scroll bars (i.e., showing them, then fading them out). Most applications included with Lion briefly demonstrate the scroll bars for windows that enjoy just appeared on the screen, enjoy just been resized, or enjoy just scrolled to a recent position (e.g., when showing the next match while searching within a document). This helps soften the blow of the missing information previously provided by always-visible scroll bars, but only a little.

    Extra UI in the scroll bar areaExtra UI in the scroll bar area

    Applications with other UI elements whose rectify placement relies on the existence of a reserved 16-pixel stripe for the scroll bar outside the content belt of the window may exist forced to array what Apple calls "legacy" scroll bars. (Apple's term for non-overlay scroll bars tells you replete you exigency to know about which way the wind is blowing on this issue.) You can view an sample of one such UI ingredient in the image on the right. The document scale pop-up menu (currently showing "100%") pushes the horizontal scroll bar to the left to Make leeway for itself. Clearly, this will not drudgery if the scroll bar overlays the content belt and is hidden most of the time. Apple suggests that such applications find recent homes for these interface elements, at which point the AppKit framework in Lion will allow them to array overlay scroll bars.

    Lion's scroll bars are a microcosm of Apple's recent philosophy for Mac OS X. This is definitely a case of reconsidering a fundamental portion of the operating system—one that hasn't changed this radically in decades, if ever. It's likewise nearly a straight port from iOS, which is in keeping with Apple's professed "back to the Mac" mission. But most importantly, it's a concrete sample of Apple's newfound dedication to simplicity.

    In particular, this change reveals the tremendous weight that Apple gives to visual simplicity. A complete lack of visible scroll bars certainly does Make the middling Mac OS X screen peek a lot less busy. A lack of visual clutter has been a hallmark of Apple's hardware and software design for years, and iOS has only accelerated this theme. Also, practically speaking, the sum of replete those 16-pixel-wide stripes reserved for scroll bars on window edges may add up to a nontrivial augment in the number of pixels available for displaying content on a Mac's screen.

    But there is a price to exist paid for this simplicity; one person's noise is another person's essential source of information. Visual information, enjoy the size and position of a scroll thumb, is one of the most efficient ways to communicate with humans. (Compare with, say, numeric readouts showing document dimensions and the current position as a percentage.)

    These sacrifices were an essential portion of the iPhone's success. The iPad, though larger, is clearly portion of the selfsame touch-based family of products, and is wisely built on the selfsame foundation. But the Mac is a different kettle of fish—and not just because the screen sizes involved may exist vastly larger, making the space savings of hidden scroll bars much less important.

    The Mac user interface, with its menus, radio buttons, checkboxes, windows, title bars, and yes, scroll bars, is built on an entirely different interactivity model than iOS. The Mac UI was built for a pixel-accurate circuitous pointing device; iOS was built for direct manipulation with one or more fingers. The visual similarity of on-screen elements and the technical feasibility of porting them from one OS to the other should not blind us to these essential differences.

    It's appealing that replete of the scrolling changes in Lion enjoy preferences that allow them to exist reverted to their pre-Lion behaviors. The defaults clearly argue the direction that Apple wants to go, but the settings to invert them—public, with actual GUIs, rather than undocumented plist hacks—suggest caution, or perhaps even some internal strife surrounding these features.

    Such caution is well-founded. Hidden scroll bars in particular enjoy trade-offs that change dramatically based on the size of the screen and the input device being used. enjoy many features in Lion, the scrolling changes are most useful and confiscate on the Macs that are closest to iOS devices in terms of size and input system (the 11-inch MacBook Air being the best example). But on a Mac Pro with dual 27" 2560x1440-pixel displays attached, Lion's scrolling defaults Make far less sense.

    Window resizing Resize widgetResize widget

    A lack of traditional scroll bars likewise means the elimination of the wee patch of pixels in the lower-right corner of a window where the upright and horizontal scroll bars meet. Since 1984, this belt has been home to the one and only control used to resize a window. Setting the scroll bar appearance preference to "always visible" restores the clickable actual estate, albeit sans the traditional "grip lines."

    Despite the unpretentious appearance, this resize control works as expected; what's unexpected is the cursor change that accompanies the action. The double-arrow cursor has been used in other operating systems for years, mostly to differentiate two-axis resizing (width and height) from single-axis resizing (height only or width only). When there's only one resize control per window, it's obvious that it can exist used to change both the width and the height. Lion's recent cursor can sordid only one thing…

    Window resizing from replete
 edges (composite image)Window resizing from replete edges (composite image)

    That's right, long-suffering switchers, Lion finally allows windows to exist resized from any edge and from replete four corners, with a special cursor for each of the eight starting points. (When a window is at its size limit, the cursors demonstrate an arrow pointing in a solitary direction—a nice touch.)

    As you can view from the image above, what Apple hasn't done is add borders to the windows. So where, exactly, attain they "grab" when resizing from a borderless window edge? There's no way around it: some pixels must exist sacrificed to the gods of Fitts's law.

    A few pixels within the outer edge of the content belt of the window (two to three, depending on where you matter from) are commandeered for window resizing purposes. You can noiseless click on these areas, and the click event will correctly propagate to the application that owns the window, but you'll exist clicking with a resize cursor instead of a established arrow cursor.

    Two to three pixels doesn't Make for a very wide target, however, which is why Apple has chosen to confiscate pixels from both sides of the window border. Four to five pixels outside the content belt of the window are likewise clickable for window resizing purposes. Clicks in these areas don't Get sent to the window (they're out of the window's bounds) and they don't Get sent to whatever happens to exist behind the lively window—you know, the thing that you ostensibly just clicked on. Effectively, Lion windows enjoy thin, invisible borders around them used only for resizing. (Unlike Mac OS 8 and 9 windows, which had real, visible borders, Lion windows can't exist dragged by their borders.)

    When overlay scroll bars are in use, the replete 16x16 pixel home of the traditional resize widget in the lower-right corner is clickable, making this noiseless the easiest target for window resizing, whether it's visible or not.

    Unzoom widgetUnzoom widget Zoom widgetZoom widget

    Lion has a few more surprises on window edges, one of which is window size-related. Windows belonging to applications that champion Lion's recent full-screen mode may demonstrate an embossed double arrow icon on the far-right side of their title bars. Clicking it will antecedent the window to fill the entire screen. Other windows, the Dock, and even the menu bar are hidden in this mode. The window's title bar likewise disappears, making it unclear how to exit this mode. But just stab the cursor at the top of the screen and the menu bar slides back down into view, containing replete the expected menus plus a reversed version of the double arrow symbol. Click the inward-facing arrows to recall the current window out of full-screen mode.


    Mac OS X has always used animation in its user interface, starting with the genie consequence over a decade ago, and really ramping up with the introduction of the Core Animation framework three years ago. Lion continues this trend. In nearly replete recent or changed applications in Lion, if something conceivable can exist animated, it is. The Finder is a Good example. Even features whose functionality hasn't actually changed in Lion, such as dragging multiple items from one window to another, are given a fresh coating of animation and fades.

    At its best, animation explicitly communicates information that was either absent or only implied before. For example, the genie animation tells the user where a window goes when it's minimized. In other cases, such as the water ripple consequence in Dashboard, animation can add a bit of fun to an interface.

    But danger lurks. A newly discovered animation might delight the user the first time it's shown, but the 350th time might not seem quite so magical. This is especially genuine if the animation adds a dilatory to the task, and if that chore is done frequently as portion of a time-sensitive overall task. The Dashboard water ripple is acceptable because adding a recent widget to the screen is an infrequent task. But if the screen rippled every solitary time a recent window appeared anywhere in the OS, users would revolt.

    Well, guess what happens every time a recent window appears on the screen in Lion? No, it's nothing as garish as a water ripple, but there is an animation. Each window starts as a tiny dot centered on the window's eventual position on the screen, then quickly animates to its replete size.

    This animation conveys no recent information. It does not narrate the user where a window came from, since the animation starts at the final position of the window. Whether or not the animation actually delays the opening of the window, it certainly feels enjoy it does, which is even more important. This kind of animation can Make Lion feel slower than Snow Leopard. And when an animation enjoy this stutters or skips a few frames due to cumbersome disk i/o or CPU usage, it makes your whole Mac feel slower, enjoy you're playing a 3D game with an inadequate video card. And for what? For what someone at Apple hopes will exist a lasting feeling of delight?

    Perhaps it could exist argued that the animation catches the eye more than a window that appears instantly (though that probably depends on the size of the window and what's behind it on the screen). For "unexpected" windows enjoy mistake dialog boxes, that could exist a benefit. But for "expected" windows (i.e., those that issue in response to deliberate user input), the powerful, primordial tug of these affecting images is an unwelcome distraction, not a benefit.

    It's conceivable that this animation could delight some users, but I enjoy a hard time believing that the enjoyment will last much past the first week. (Interestingly, this animation does not play in invert when a window is closed. This, perversely, makes window closing feel faster than window opening in Lion.)

    Unlike the scrolling behaviors discussed earlier, there are no user-visible preferences for these recent animations, which makes it replete the more famous for Apple to strike a Good balance. In my estimation, Lion crosses the line in a few places; the recent window animation is the most egregious example. I peek forward to discovering a way to disable it. [Update: here it is: defaults write NSGlobalDomain NSAutomaticWindowAnimationsEnabled -bool NO]

    Here's to the crazy ones

    Bruce Tognazzini, founder of the Apple Human Interface Group and 14-year Apple veteran (1978-1992), is best known as the man behind the publication of the Apple Human Interface Guidelines. In 1992, he published a bespeak of his own: Tog on Interface. Most of the examples in the bespeak were taken from his drudgery at Apple. Here's an excerpt from pages 156-157:

    Natural objects enjoy different perceivable characteristics, among which people can easily discriminate. recall the bristlecone pine. The oldest animate thing on earth, it has been formed and shaped by the wind and scarred by thousands of years of existence. The youngest school kids peek at it and know there must exist a lot of wind around there. They know the pine may exist even older than their father. They likewise know, to a certainty, that it is a tree.

    Hypercard "Home" iconsHypercard "Home" icons

    Kristee Kreitman Rosendahl, liable for not only the realistic design of HyperCard, but likewise much of its spirit, created a collection of Home icons that shipped with the product.

    No one has ever shown confusion at seeing various dinky houses on various cards. Never once has someone turned around and said, "Gee, this dinky house has three windows and seems to exist a Cape Cod. Will that recall me to a different Home card than that two-story bunk house back in the other section?" People are designed to exploit multiplexed meanings gracefully, without conscious thought.

    In System 7, they multiplexed the sense of system extensions, by developing a characteristic "generic" extension look, to which developers can add their own unique peek for their specific product. As the "bandwidth" of the interface increases, these kinds of multiplexings will become more and more practical.

    System 7 extension iconsSystem 7 extension icons

    This is Tog, godfather of the old-school Apple Human Interface Guidelines, stating emphatically that interface elements attain not enjoy to peek exactly the selfsame in order for their role to exist discerned. In fact, in the final sentence, Tog predicts that increased computing power will lead to more diverse representations. The increased "bandwidth" of user interfaces that Tog wrote about almost 20 years ago has now approach to pass, and then some.

    Examples of "multiplexed meanings" in Mac OS X are not hard to find. peek at the Dock, which has changed appearance several times during the history of Mac OS X while noiseless remaining immediately identifiable. And, as discussed earlier, nearly every gauge GUI control has changed its appearance in Lion. As Tog notes, people are excellent at discarding unimportant details and focusing on the most remarkable aspects of an item's appearance.

    Now, keeping replete this in mind, I invite you to peer upon this screenshot of the version of iCal that ships with Lion.

    A stitch in time saves…something, presumably

    Enlarge / A stitch in time saves…something, presumably

    When this change was first revealed in the second developer preview of Lion, there was much gnashing of teeth. But question yourself, is the role of every control in the toolbar clear? Or rather, is it any less lucid than it would exist if iCal used the gauge Mac OS X toolbar appearance?

    The immediate, visceral negative reaction to the rich Corinthian leather appearance had dinky to attain with usability. What it came down to—what first impressions enjoy these always seem to approach down to—is whether or not you think it's ugly. People will recall "really cool-looking but slightly harder to use" over "usable but ugly" any day.

    But there's something much more famous than the change in appearance going on here. Lion's iCal doesn't peek different in an arbitrary way; it's been changed with purpose. After the initial stitched-leather shock wore off, Apple watchers everywhere leapt on the recent iCal's deeper sin: its skeuomorphic design. From Wikipedia (emphasis added):

    A skeuomorph is a derivative protest that retains ornamental design cues to a structure that was necessary in the original. Skeuomorphs may exist deliberately employed to Make the recent peek comfortably conventional and familiar, such as copper cladding on zinc pennies or computer printed postage with circular town appellation and cancellation lines. An alternative definition is "an ingredient of design or structure that serves dinky or no purpose in the artifact fashioned from the recent material but was essential to the protest made from the original material."

    Apple has been down this road before, most notably with the QuickTime 4.0 player application which included radiant ideas enjoy a "dial" control for adjusting the volume. Dials drudgery much in the real, physical world, and are certainly close to most people. But a dial control in the context of a 2D mouse-driven GUI is incongruous and maladroit at best, and completely incomprehensible at worst.

    The brushed metal appearance of the QuickTime player would later inspire an officially supported Mac OS X window appearance starting in version 10.2, only to exist dropped completely five years later in 10.5's magnificient interface unification. Now, three years after that, the pendulum is swinging in the other direction again—and hard.

    In the case of iCal, Apple has aped the appearance of an analogous physical protest (a tear-off paper calendar) but retained the behavior of gauge Mac OS X controls. This avoids the problems of the QuickTime 4.0 player's dial control, but it's far from a clean win.

    The grief is, the recent iCal looks so much enjoy a close physical protest that it's effortless to start expecting it to behave enjoy one as well. For example, iCal tries very hard to sell the tear-off paper calendar illusion, with the stitched binding, the tiny remains of already-removed sheets, and even a page curl animation when advancing through the months. But can you grab the corner of a page with your mouse and tear it off? Nope, you enjoy to exhaust the arrow buttons or a keyboard command, just enjoy in the previous version of iCal. Can you scribble in the margins? Can you cross off days with a pen? Can you riffle through the pages? No, no, and no.

    At the selfsame time, iCal is noiseless constrained by some of the limitations of its physical counterpart. A paper calendar must pick a solitary way to crash up the days in the year. Usually, each page contains a month, but there's no judgement for a virtual calendar to exist limited in the selfsame way. When dealing with events that span months, it's much more convenient to view time as a continuous stream of weeks or days. This is especially genuine on big desktop monitors, where zooming the iCal window to replete screen doesn't demonstrate any more days but just makes the days in the current month larger.

    The recent version of Address bespeak in Lion is an even more egregious example.

    These graphics are writing checks this interface can't cash Enlarge / These graphics are writing checks this interface can't cash

    Address bespeak goes so far in the direction of imitating a physical analog that it starts to impair the identification of gauge controls. The window widgets, for example, are so integrated into the design that they're effortless to overlook. And as in iCal, the grotesque detail of the appearance implies functionality that doesn't exist. Pages can't exist turned by dragging, and even if they could, the number of pages on either side of the spine never changes. The window can't exist closed enjoy a book, either. That red bookmark can't exist pulled up or down or removed. (Clicking it actually turns the page backwards to disclose the list of groups. Did you guess that?) The three-pane view (groups → people → detail) is gone, presumably because a bespeak can't demonstrate three pages at once. Within each paper "page" sits, essentially, an excerpt from the user interface of the previous version of Address Book. It's a mixed metaphor that sends mixed signals.

    These newly redesigned Mac OS X applications are clearly inspired by their iOS counterparts, which stand similar graphical flourishes and skeuomorphic design elements. (Address bespeak in particular is a deceased ringer for the Contacts app on the iPad.) In iOS, the inability to whirl pages with the flick of a finger or yank out that tantalizing red bookmark is even more frustrating. In both environments, when the behaviors seemingly promised by the graphical design aren't delivered, replete this artwork that was so clearly labored over fades into the background. The application trains us to ignore it. What was once, at best, a momentary amusement is reduced to visual noise.

    In 2011, we're far past the point where computer interfaces exigency to reference their forebearers in the physical world in order to exist understandable (though it's feasible Apple thinks the familiarity of such designs is noiseless an effective way to reduce intimidation, especially for novice users). At the selfsame time, hardware and software enjoy advanced to the point where there's now ample "bandwidth" (to exhaust Tog's term) to champion visual and functional nuances beyond the bare necessities.

    Interface designers are faced with the challenge of how best to exhaust the glut of resources now at their disposal. As Lion's iCal and Address bespeak applications demonstrate, an alternate description of this situation might exist "enough rope to hang yourself."

    Window management

    Over the years, Apple has added several features that could loosely exist defined as "window management aids." The first, and arguably most successful, was Exposé, introduced in Panther back in 2003. Two years later, Tiger shipped with Dashboard, which provided a dedicated screen for wee "widget" windows, keeping them off the main screen. In 2007, Leopard brought official champion for virtual desktops to Mac OS X under the appellation Spaces.

    Each of these features came with its own set of configurable keyboard shortcuts, burning screen corners, and (eventually) multi-touch gestures. While each was understandable and useful in isolation, it was up to each user to device out how best to incorporate them into a workflow. In Lion, Apple has taken a stab at consolidation under the umbrella appellation of Mission Control. Each individual feature noiseless exists, albeit in slightly more limited forms, but activating one thing now provides access to them all.

    Using any one of the supported Mission Control activation methods—a keyboard shortcut, a burning screen corner, or a four-finger upwards swipe—causes the current desktop picture to retreat slightly into the center of the screen, revealing behind it their conventional friend the linen pattern. Overlaid on this are groups of windows, badged by the icons of the applications to which they belong. Along the top of the screen sit replete open Spaces. (In Lion, each full-screen window creates a recent Space, so those windows issue at the top rather than grouped with the other windows from the selfsame application.) Dashboard is likewise (optionally) given its own Space.

    Mission Control: Exposé + Spaces + Dashboard Enlarge / Mission Control: Exposé + Spaces + Dashboard

    A surprising number of things can exist done from this screen. As with Exposé, clicking on any window will bring it to the front. Windows can likewise exist dragged into any of the available Spaces (excluding Dashboard and those that accommodate a solitary full-screen window). affecting the cursor (or dragging a window) to the upper-right corner of the screen causes a panel with a "+" character to appear; clicking this creates a recent space. Holding down the option key makes Dashboard-style "close" widgets issue on any non-fullscreen-window Spaces (except the original Desktop Space, which can never exist closed).

    The biggest limitation of this recent arrangement is that Spaces are now confined to a one-dimensional line of virtual desktops. Four-finger swiping between spaces feels great, but there's no wrap-around when you hit the end.

    As expansive a step down as this is from the much more flexible grid arrangement of Spaces in earlier versions of Mac OS X, the recent limitations are probably a Good idea. The recent behavior of full-screen windows and the surprisingly natural-feeling four-finger swipes used to switch between them and enter Mission Control means that many more Mac users will likely find themselves using these recent features than ever used the combination of Exposé and Spaces in earlier versions of the OS. A simple line of spaces with no wrap-around provides a safe, understandable environment for replete these recent Spaces users.

    For the experts, well, consolidation always has its price. In this case, as in many others, Apple has decided that the Good of the many outweighs the Good of the few.

    Application management

    For replete its warts, the radical simplification of application management brought to Mac OS X by the Dock really has benefitted the platform. As I wrote in my ten year Mac OS X retrospective, "For every user who continues to exist frustrated by the Dock's limitations, there are thousands of others who are buoyed in their computing efforts by its reassuring simplicity and undemanding design."

    But the Dock falls short, especially for novice users, as an application launcher. Or rather, it falls short if the application to exist launched isn't actually in the Dock. Most novice users I know want to enjoy every application they are likely to exhaust available in the Dock at replete times. As these users gain experience, the Dock can become a very crowded place. But why are these increasingly Mac-savvy users stuffing their Docks to the gills rather than limiting its contents to just the applications they exhaust most frequently?

    The reply lies in how applications not in the Dock are located and launched. Choices comprehend the Finder, Spotlight, or (I suppose) a Terminal window. affecting from an always-visible line of colorful icons that's front and center on the screen to any one of those alternatives represents a huge augment in conceptual and mechanical complexity.

    If you don't understand how typing the appellation of an application into a search box can exist so much more difficult than clicking an icon in the Dock, I insinuate that you enjoy not spent enough time with novice users. Such users often don't even know the appellation of the application they want—or if they do, they don't know how to spell it. That's before considering the frequent disorientation caused by the rapid-fire search results refinement animation in the Spotlight menu, or the existence of multiple files whose contents or names accommodate the string being searched for. And this replete assumes novices know (or remember) what Spotlight is and how to activate it in the first place.

    The jump in complexity from the Dock to the Finder, I think, needs less explanation. As a general rule, novice users just don't understand the file system. They don't understand the hierarchy of machines, devices, and volumes; they don't grasp the concept of the current working directory; they don't know how to identify a file or folder's position within the hierarchy. panic of the file system practically defines novice users; it is usually the last and biggest hurdle in the journey from timorous experimentation to basic technical competence.

    To achieve it another way, your dad can't find it if it's not in the Dock. (Well, my dad can't, anyway. Sorry to replete the Mac-savvy dads out there; I am one, after all.)

    In Lion, Apple aims to fill that gap with an application launching interface that's meant to exist as effortless to exhaust as the Dock while providing access to every application on the system. It's called Launchpad, and you'll exist forgiven for thinking that it looks enjoy yet another interface ingredient shamelessly ported from iOS.

    Launchpad: iOS’s SpringBoard on your Mac Enlarge / Launchpad: iOS’s SpringBoard on your Mac

    Launchpad can exist activated with a Dock icon (which, importantly, is in the Lion Dock by default), a multitouch signal (a moreorless maladroit pinch with the thumb and three fingers), or by dragging the mouse cursor to a designated corner of the screen. The grid of application icons that appears doesn't just peek enjoy iOS's SpringBoard, it likewise behaves enjoy it, right down to the "folders" created by dragging icons on top of each other.

    Holding down the option key makes replete the icons sprout nigh widgets as they start to wiggle. Swiping right and left on the touchpad or with a click and drag of the mouse will scramble from screen to screen, accompanied by a close iOS-like dotted page indicator.

    Launchpad “folders” Enlarge / Launchpad “folders”

    Launchpad will find applications in the gauge /Applications folder as well as ~/Applications (i.e., a folder named "Applications" in your home directory), and any subfolders within them. Applications in the ~/Downloads folder or on the desktop are not detected, which may actually exist a problem for Mac users who enjoy not yet figured out how to perform drag-and-drop application installations—yet another belt where the Mac App Store will waiton Make things simpler.

    Mac App Store download progressMac App Store download progress

    Speaking of which, when purchasing an application in the version of the Mac App Store that ships with Lion, the application icon leaps out of the Mac App Store window and lands in the next available position in the Launchpad grid, with an iOS-like progress bar overlaid on the recent application's icon. If the Launchpad icon is in the Dock, it displays a similar progress bar and the icon bounces once when the download finishes.

    Both serve as examples of animation that conveys useful information. "Here's where the application you just purchased has 'landed' on your Mac," the animation says. "To find it again, click the icon that just bounced in your Dock."

    Given the wealth of excellent third-party application launchers available for the Mac, I'm not certain there's any judgement for an expert user to exhaust Launchpad instead of their current favorite alternative. But unlike, say, the Dock, Launchpad is easily ignored. whirl off the gesture, deactivate the burning corner, and remove the icon from the Dock and you'll never enjoy to view it.

    For everyone else, however, Launchpad will provide a huge improvement in usability. Even expert users should exist excited about its arrival because it should Make telephone or e-mail-based family technical champion a bit easier.

    Document model

    Lion introduces what Apple calls, with characteristic conviction, a "modernized" document model. I'm inclined to correspond with this word choice. enjoy so many other aspects of Lion, document management is attempting to shed its legacy baggage—and there's plenty to shed. The conventions governing the interaction between users, applications, and documents enjoy not changed much since the personal computer became common in the early 1980s.

    Apple first attempted a minor revolution in this belt with OpenDoc in the 1990s. Instead of launching an application in order to create a document, OpenDoc promised a world where the user would open a document and then drudgery on it using an interchangeable set of components created by multiple vendors. In other words, OpenDoc was document-centric rather than application-centric.

    The changes in OpenDoc promised to radically shift the poise of power in the application software market. But powerful software companies enjoy Microsoft and Adobe were not particularly motivated to crash their popular, full-featured applications into smaller components that customers could fuse and match with components from other vendors. At the time OpenDoc was released, Apple was nearing the nadir of its popularity and influence in the industry. Predictably, OpenDoc died on the vine.

    Fast-forward to today, where a much more powerful and confident Apple takes another crack at the selfsame area. The most pressing problem, today's Apple has decided, is not the interaction between application code and document data, but rather the interaction between the user and the computer.

    Despite decades of public exposure to personal computers, human expectations and habits enjoy stubbornly refused to align with the traditional model of creating, opening, and saving documents. The tales of woe enjoy become clichés:

  • The student who writes for an hour without saving and loses everything when the application crashes.
  • The businessman who accidentally saves over the "good" version of a document, then takes it upon himself to independently reinvent version control—poorly—by compulsively saving each recent revision of every document under slightly different names.
  • The Mac power user who reflexively selects the "Don't Save" button for one document after another when quitting an application with many open windows, only to accidentally lose the one document that actually had famous changes.
  • The father who swears he saved the famous document, but can't, for the life of him, bethink where it is or what he called it.
  • At this point, they can no longer summon this a problem of education. We've tried education for years upon years; children enjoy been born and grown to adulthood in the PC era. And yet even the geekiest among us enjoy lost data, time, or both due to a "stupid" mistake related to creating, opening, and saving documents.

    And so Apple's decree in Lion is as it was on the original Macintosh in 1984, and as it is on iOS today: the machine must serve the human, not the other way around. To that end, Apple has added APIs in Lion that, when used properly, enable the following experience.

  • The user does not enjoy to bethink to save documents. replete drudgery is automatically saved.
  • Closing a document or quitting an application does not require the user to Make decisions about unsaved changes.
  • The user does not enjoy to bethink to save document changes before causing the document's file to exist read by another application (e.g., attaching an open document with unsaved changes to an e-mail).
  • Quitting an application, logging out, or restarting the computer does not sordid that replete open documents and windows enjoy to exist manually re-opened next time.
  • Earlier versions of Mac OS X supported a shape of automatic saving. If you had an open TextEdit document with unsaved changes, TextEdit would (eventually) save a backup copy of the file with the text " (Autosaved)" appended to the file name. If the application crashed or the Mac lost power, you could retrieve (some of) your unsaved changes by finding the autosaved file and opening it.

    Lion introduces a variant of this practice: autosave in place. Rather than creating a recent file alongside the original, Lion continuously saves changes directly to the open document. It does this when there are big document changes, during idle times, or on claim in response to requests from other applications for access to the document's data.

    For replete of this to work, applications must exist updated to exhaust the recent APIs. In particular, a recent File Coordination framework must exist used in order for an application to notify another that it wants to access a document that's currently open. The application that has the document open will then trigger an autosave to disk before allowing the requesting application to reference the document's data. Attaching a document to an e-mail or using Quick peek in the Finder are two examples of when this might happen.

    At this point, a dinky bit of "geek panic" might exist setting in. For those of us who understand the pre-Lion document model and enjoy been using it for decades, the understanding that they are no longer in control of when changes to open documents are saved to disk seems insane! What if I accidentally delete a huge swath of text from a document and then Lion decides to autosave immediately afterwards?

    Not every change is meant to exist saved, after all. The practice of speculatively making radical changes to a document with the console of knowing that None of those changes are permanent until they hit ⌘S is something experienced Mac users recall for granted and may exist loath to give up.

    The artist formerly known as “Save”The artist formerly known as “Save”

    I confess, I omitted one detail from the list of changes enabled by Lion's modern document model. Here it is:

  • The user does not enjoy to manually manage multiple copies of document files in order to retrieve conventional versions.
  • If you noiseless don't Get it, check out the detail in the File menu formerly known as "Save." It now reads "Save a Version" instead. Every time a Lion-savvy application autosaves a document, it stores a copy of the previous version before it overwrites the file with the recent data. A pop-up menu in the title bar of each document window provides access to previous versions.

    A menu in the title bar provides access to previous versions of a fileA menu in the title bar provides access to previous versions of a file

    Select the "Browse replete Versions…" menu detail to enter a Time Machine-like space-themed screen showing replete previous versions of the file. Using this interface, the document can exist reverted to any earlier version, or snippets of data from earlier versions may exist copied and pasted into the current version. Though the star field background and surrounding timeline interface are provided automatically, the document windows themselves are actual windows within the application. They can exist scrolled and manipulated in any way allowed by the application, though the contents of previous versions may not exist modified.

    Document version browser…in spaaaaace! Enlarge / Document version browser…in spaaaaace!

    The gauge Cocoa document framework will manage many of the details for application developers, including automatically purging very conventional versions of files. The document versioning interface shown above is likewise integrated with Time Machine, showing both locally stored file versions and older versions that only exist on the Time Machine backup volume. Going forwards or backwards in the document timeline is accompanied by a super star-field "warp" animation.

    Restoring the document to an earlier state actually just pushes a duplicate of that state to the front of the stack of replete changes. In other words, restoring a document to its state as of an hour ago does not discard replete the changes that happened during that hour.

    Returning to the title bar pop-up menu, the "Revert to last Saved Version" menu detail returns the document to its last explicitly saved state (i.e., what it looked enjoy the last time the user typed ⌘S or selected the "Save a Version" menu item). "Duplicate" will create a recent document containing the selfsame data as the current document. Finally, the "Lock" detail will forestall any further changes to the document until it is explicitly unlocked by the user. Documents will likewise automatically exist locked if they're not modified for a dinky while. The auto-lock time is configurable in the "Options…" screen of the Time Machine preference pane (of replete places), with values from one day to one year. The default is two weeks.

    The auto-lock dilatory setting, cleverly hidden in the Time Machine preference paneThe auto-lock dilatory setting, cleverly hidden in the Time Machine preference pane

    There is no graphical interface to previous versions of documents outside of an application. Previous versions can't exist viewed or restored from within the Finder, for example. Forcing replete version manipulation to exist within the application is limiting, but it likewise neatly solves the problem of how to present document contents with replete fidelity—beyond what Quick peek offers—when looking at past revisions.

    One unexpected implication of autosave is that it makes quitting applications much less painful. If you've ever had to quickly log out or shut down a Mac that has been up and working hard for weeks or months, you know how abominable it is to enjoy to wade through umpteen dialog boxes, each demanding a conclusion about unsaved changes before allowing you to continue.

    These are not effortless questions, especially for files that may enjoy been open for a long time. achieve aside deciding whether the changes are worth saving; can you even bethink what the unsaved changes are? Were they intentional, or did you accidentally lanky on the keyboard and delete a selected detail some time last week? Now multiply this pickle by the number of open documents with unsaved changes—and imagine you're in a hurry. It's not a pleasant experience.

    Autosave eliminates these hassles. Quitting an application that supports autosave happens instantly, with no additional user input required—always.

    Of course, by quitting an application (or quitting replete applications by logging out or restarting) you're likewise losing replete of your accumulated state: replete your open documents, the size and position of their windows, scroll positions, selection state. Losing state can prove even more painful than playing "20 questions" with a swarm of "unsaved changes" dialog boxes. Assuming you can bethink what documents you had open, can you find them again?

    Lion offers recent APIs to address this problem as well. A suite of recent state encoding/decoding hooks allow Lion applications to save and restore any and replete aspects of document state. Upon relaunch, an application is expected to restore replete the documents open when it was last quit, with replete their state preserved.

    So, how's that "geek panic" now? noiseless there, huh? Well, let me try to reassure you. As a committed user of a much Mac text editor that, years ago, implemented its own version of almost replete the document management features described so far, I can narrate you that you Get used to it very quickly. Spoiled by it, in fact. Ruined by it, some would say. Yes, it's a very different model from the one we're replete used to. But it's likewise a better model—not just for novices, but for geeks too.

    Think about it: never lose data because you forgot to save. Quit applications with impunity. Retrieve conventional versions of documents at any time, in whole or in part. Build up a nice arrangement of open documents and windows, knowing that your hard drudgery will not exist trashed the next time you quit the application or exigency to restart for an OS security update.

    The final piece of the puzzle is not strictly document-related, but it puts the bow on the package. When logging out or restarting, Lion presents an option (selected by default) to restore replete open applications when you next log in. And relaunching a Lion-savvy application, of course, causes it to restore its open documents.

    Putting it replete together, this means that you can log out or shut down your Mac without being asked any questions by needy applications and without losing any of your data or window state. When you next log in, the screen should peek exactly the selfsame as it did just before you logged out. (In fact, Lion appears to "cheat" and briefly presents a static image of your earlier screen while it works on relaunching your apps and restoring your open documents. Sneaky, but an effective way to Make state restoration feel faster than it really is.)

    Process model

    If you were flipping out over the document changes described in the previous section, buckle up, because the discomfort plane is about to climb yet again.

    The wee indicator lights shown beneath running applications in the Dock are now optional in Lion.

    Three of these applications are runningThree of these applications are running

    In pre-release builds of Lion, replete applications in the Dock looked exactly the same, running or otherwise. At the last minute, it seems Apple chickened out and enabled the indicator lights by default.

    Dock indicator lights preferenceDock indicator lights preference

    Apple's message with this feature is a simple one, but likewise one that the nerdly mind rebels against: "It doesn't matter if an application is running or not. You shouldn't care. desist thinking about it." Geek panic!

    Remain calm. Let's start with the APIs. Sudden Termination, a feature that was introduced in Snow Leopard, allows applications to argue to the system that it's safe to abolish them "impolitely" (i.e., by sending them SIGKILL, causing them to terminate immediately, with no haphazard for potentially time-consuming clean-up operations to execute). Applications are expected to set this bit when they're certain they're not in the middle of doing something, enjoy no open files, no unflushed buffers, and so on.

    This feature enables Snow Leopard to log out, shut down, and restart more quickly than earlier versions of Mac OS X. When it can, the OS simply kills processes instead of politely asking them to exit. (When Snow Leopard was released, Apple made certain its own applications and daemon processes supported Sudden Termination, even if third-party applications didn't.)

    Lion includes a recent feature called Automatic Termination. Whereas Sudden Termination lets an application narrate the system when it's okay to terminate it with extreme prejudice, Automatic Termination lets an application narrate the system that it's okay to politely question the program to exit.

    But wait, isn't it always okay for the OS to politely question an application to exit? Isn't that what's always happened in Mac OS X on logout, shutdown, or restart? Yes, but what makes Automatic Termination different is when and why this might happen. In Lion, the OS may terminate applications that are not in exhaust in order to reclaim resources—primarily memory, but likewise things enjoy file descriptors, CPU cycles, and processes.

    You read that right. Lion will quit your running applications behind your back if it decides it needs the resources, and if you don't issue to exist using them. The heuristic for determining whether an application is "in use" is very conservative: it must not exist the lively application, it must enjoy no visible, non-minimized windows—and, of course, it must explicitly champion Automatic Termination.

    Automatic Termination works hand-in-hand with autosave. Any application that supports Automatic Termination should likewise champion autosave and document restore. Since only applications with no visible windows are eligible for Automatic Termination, and since by default the Dock does not argue whether or not an application is running, the user might not even notice when an application is automatically terminated by the system. No dialog boxes will question about unsaved changes, and when the user clicks on the application in the Dock to reactivate it, it should relaunch and issue exactly as it did before it was terminated.

    This is effectively a deprecation of the Quit command. It also, perhaps coincidentally, solves the age-old problem of former Windows users expecting applications to terminate when they no longer enjoy any open windows. When Automatic Termination is enabled in an application, that's exactly what will happen—if and when the system needs to reclaim some resources, that is.

    As if replete of this isn't enough, Lion features one final application management twist. When an application is terminated in Lion, replete the accustomed things issue to happen. If the running application indicator is enabled, the wee dot will evaporate from beneath the application's Dock icon. Assuming it's not a permanent resident, the application icon will evaporate from the Dock. The application will no longer issue in the command-tab application switcher, or in Mission Control. You might therefore conclude that this application's process has terminated.

    A quick trip to the Activity Monitor application or the "ps" command-line utility may dissuade you of that notion. Lion reserves the right to withhold an application's process around just in case the user decides to relaunch it. Upon relaunch, the application appears to start up instantly—because it was never actually terminated, but was simply removed from replete parts of the GUI normally occupied by running applications.

    That's right, gentle readers. In Lion, an ostensibly "running" application may enjoy no associated process (because the operating system automatically terminated it in order to reclaim resources) and an application may enjoy a process even when it doesn't issue to exist running. Applications without processes. Processes without applications. Did Lion just blow your mind?

    The pitch

    The application and document model changes in Lion are a radical crash with the past—the past of the desktop, that is. Everything described above has existed since day one on Apple's mobile platform. Indeed, iOS is the most compelling dispute in favor of the changes in Lion. For every objection offered by a long-time personal computer aficionado, there are millions of iOS users countering the dispute every day with their fingers and their wallets.

    These changes in Lion are meant to reduce the number of things the user has to trust about. And while you may think you really attain exigency to trust about when your documents are saved to disk or when the reminiscence occupied by an application is returned to the system, you may exist surprised by how dinky you think about these things once you become accustomed to the computer managing them for you. If you're an iOS user, think about how often you've wanted a "Save" button in an app on your iPhone or iPad, for example.

    So that's the pitch: Lion will bring the worry-free usability of iOS application and document management to the Mac. For the vast majority of Mac users, I think it will exist an effortless sale.

    The reality

    There's a common thread running through replete of the application and document model features described above: they're replete opt-in, and developers must add code to their applications to champion them. Apple has some faculty to hasten the transition to Lion-savvy applications through evangelism, positive reinforcement (the carrot), and the increasing popularity of the Mac App Store (the stick). But no matter what Apple does, the idyllic image of an iOS-like suffer on your Mac will recall a long time to materialize.

    In the meantime, it's effortless to envision a frustrating hodgepodge of conventional and recent Mac applications running on Lion, making users second-guess their hard-won computing instincts at every turn. What I think will actually happen is that the top-tier Mac developers will quickly add champion for some or replete of these recent features and users will start to peek down on applications that noiseless behave the "old way." I'm certain that's how Apple hopes things whirl out, too.


    The previous release of Mac OS X focused on internal changes. My review did the same, covering compiler features, programming language extensions, recent libraries, and other details that were mostly invisible to end-users.

    Lion is most definitely not an internals-focused release, but it's likewise expansive enough that it has its share of famous changes to the core OS accompanying its more obvious user-visible changes. If this is your first time reading an Ars Technica review of Mac OS X and you've made it this far, exist warned: this section will exist even more esoteric than the ones you've already read. If you just want to view more screenshots of recent or changed applications, feel free to skip ahead to the next section. They nerds won't think any less of you.


    Apple's approach to security has always been a bit unorthodox. Microsoft has spent the last several years making security a top priority for Windows, and has done so in a very public way. Today, Windows 7 is considered vastly more secure than its widely exploited ancestor, Windows XP. And despite the fact that Microsoft now distributes its own virus/malware protection software, a burgeoning market noiseless exists for third-party antivirus software.

    Meanwhile, on the Mac, Apple has only very recently added some basic malware protection to Mac OS X, and it did so quietly. Updates enjoy been similarly quiet, giving the impression that Apple will only talk about viruses and malware if asked a direct question about a specific, actual piece of malicious software.

    This approach is typical of Apple: don't announce anything until you enjoy something meaningful to say. But it can exist maddening to security experts and journalists alike. As for end-users, well, until there is a security problem that affects more than a tiny minority of Mac users, it's hard to find an sample of how Apple's policies and practices enjoy failed to protect Mac users at least as well as Microsoft protects Windows users.


    Just because Apple is quiet, that doesn't sordid it hasn't been taking actual steps to ameliorate security on the Mac. In Leopard, Apple added a basic shape of sandboxing to the kernel. Many of the daemon processes that Make Mac OS X drudgery are running within sandboxes in Snow Leopard. Again, this was done with dinky fanfare.

    Running an application inside a sandbox is meant to minimize the damage that could exist caused if that application is compromised by a piece of malware. A sandboxed application voluntarily surrenders the faculty to attain many things that a established process race by the selfsame user could do. For example, a established application race by a user has the faculty to delete every solitary file owned by that user. Obviously, a well-behaved application will not attain this. But if an application becomes compromised, it may exist coerced into doing something destructive.

    In Lion, the sandbox security model has been greatly enhanced, and Apple is finally promoting it for exhaust by third-party applications. A sandboxed application must now comprehend a list of "entitlements" describing exactly what resources it needs in order to attain its job. Lion supports about 30 different entitlements which range from basic things enjoy the faculty to create a network connection or to listen for incoming network connections (two sever entitlements) to sophisticated tasks enjoy capturing video or noiseless images from a built-in camera.

    It might seem enjoy any nontrivial document-based Mac application will, at the very least, exigency to declare an entitlement that will allow it to both read from and write to any directory owned by the current user. After all, how else would the user open and save documents? And if that's the case, wouldn't that entirely subjugate the purpose of sandboxing?

    Apple has chosen to solve this problem by providing heightened permissions to a particular class of actions: those explicitly initiated by the user. Lion includes a trusted daemon process called Powerbox (pboxd) whose job is to present and control open/save dialog boxes on behalf of sandboxed applications. After the user selects a file or directory into which a file should exist saved, Powerbox pokes a hole in the application sandbox that allows it to perform the specific action.

    A similar mechanism is used to allow access to recently opened files in the "Open Recent" menu, to restore previously open documents when an application is relaunched, to exploit drag and drop, and so on. The goal is to forestall applications from having to request entitlements that allow it to read and write arbitrary files. Oh, and in case it doesn't scramble without saying, replete sandboxed applications must exist signed.

    Here are a few examples of sandboxed processes in Lion, shown in the Activity Monitor application with the recent "Sandbox" column visible:

    Sandboxed processes in LionSandboxed processes in Lion

    Earlier, the Mac App Store was suggested as a way Apple might expedite the adoption of recent Lion technologies. In the case of sandboxing, that has already happened. Apple has decreed that replete applications submitted to the Mac App Store must exist sandboxed, starting in November.

    Privilege separation

    One limitation of sandboxing is that entitlements apply to an entire process. A sandboxed application must therefore possess the superset of replete entitlements required for each feature it provides. As we've seen, the exhaust of the Powerbox daemon process prevents applications from requiring arbitrary access to the file system by delegating those entitlements to another, external process. This is a specific case of the general principle called privilege separation.

    The understanding is to crash up a tangled application into individual processes, each of which requires only the few entitlements necessary to perform a specific subset of the application's total capabilities. For example, deem an application that needs to play video. Decoding video is a tangled and performance-sensitive process which has historically led to inadequate protection against buffer overflows and other security problems. An application that needs to array video will likely attain so using libraries provided by the system, which means that there's not much a third-party developer can attain to patch vulnerabilities where they occur.

    What a developer can attain instead is segregate the video decoding chore in its own process with severely reduced privileges. A process that's decoding video probably doesn't exigency any access to the file system, the network, the built-in camera and microphone, and so on. It just needs to accept a stream of bytes from its parent process (which, in turn, probably used Powerbox to gain the faculty to read those bytes from disk in the first place) and revert a stream of decoded bytes. Beyond this simple connection to its parent, the decoder can exist completely walled off from the comfort of the system. Now, if an exploit is create in a video codec, a malicious hacker will find himself in control of a process with so few privileges that there is dinky harm it can attain to the system or the user's data.

    Though this was just an example, the QuickTime Player application in Lion does, in fact, delegate video decoding to an external, sandboxed, extremely low-privileged process called VTDecoderXPCService.

    QuickTime Player with its accompanying sandboxed video decoder processQuickTime Player with its accompanying sandboxed video decoder process

    Another sample from Lion is the Preview application, which completely isolates the PDF parsing code (another historic source of exploits) from replete access to the file system.

    Putting aside the security advantages of this approach for a moment, managing and communicating with external processes is kindly of a pain for developers. It's certainly less convenient than the traditional approach, with replete code within a solitary executable and no functionality more than a role summon away.

    Once again in Lion, Apple has provided a recent set of APIs to encourage the adoption of what it considers to exist a best practice. The XPC Services framework is used to manage and communicate with these external processes. XPC Service executables are contained within an application's bundle. There is no installation process, and they are never copied or moved. They must likewise exist portion of the application's cryptographic signature in order to forestall tampering.

    The XPC Service framework will launch an confiscate external process on demand, track its activity, and pick when to terminate the process after its job is done. Communication is bidirectional and asynchronous, with FIFO message delivery, and the default XPC process environment is extremely restrictive. It does not inherit the parent process's sandbox entitlements, Keychain credentials, or any other privileges.

    The reward for breaking up an application into a collection of least-privileged pieces is not just increased security. It likewise means that a crash in one of these external processes will not recall down the entire application.

    We've seen this kindly of privilege separation used to much consequence in recent years by Web browsers on several different platforms, including Safari on Mac OS X. Lion aims to extend these advantages to replete applications. It likewise makes Safari's privilege separation even more granular.

    Safari in Lion is based on WebKit2, the latest and greatest iteration of the browser engine that powers Safari, Chrome, and several other desktop and mobile browsers. Safari in Snow Leopard already separated browser plug-ins such as glance into their own processes. (Adobe should not deem this an insult; Apple does the selfsame with its own QuickTime browser plug-in.) As if to further that point, WebKit2 separates the entire webpage rendering chore into an external process. The number of excuses for the Safari application to crash is rapidly decreasing.

    As the WebKit2 website notes, Google's Chrome browser uses a similar approach to segregate WebKit (version 1) from the comfort of the application. WebKit2 builds the separation directly into the framework itself, allowing replete WebKit2 clients to recall handicap of it without requiring the custom code that Google had to write for Chrome. (Check out the process architecture diagrams at the WebKit2 site for more circumstantial comparisons with pre-Lion WebKit on Mac OS X and Chrome's exhaust of WebKit.)

    Automatic Reference Counting

    Since 2005, I've been very publicly concerned about the long-term prospects of Apple's programming language and application framework, Objective-C and Cocoa, going so far as to speculate about a feasible technological pass a few years in the future.

    When the future arrived, I revisited the issue of Apple's language and API future in light of Apple's histrionic entrance into the mobile market and the unprecedented growth this has enabled. You can read my conclusions for yourself, but the bottom line is that I'm noiseless concerned about the issue—and think Apple should exist too. Success hides problems, and Apple has been so very successful in recent years.

    Enter (and exit) garbage collection

    Apple has done a tremendous amount of drudgery to modernize its progress platform, including completely replacing its compiler, overhauling its IDE, and adding features and recent syntax to the Objective-C language itself.

    All of these things are great, but None address my specific concerns about reminiscence management. Apple did eventually view fortunate to add garbage collection to Objective-C, but my panic that Apple wouldn't really consign to garbage collection in Objective-C turned out to exist well-founded. Today, years after the introduction of this feature, very few of Apple's own applications exhaust garbage collection.

    There's a Good judgement for this. Runtime garbage collection is simply a indigent fortunate for Objective-C. For replete its syntactic simplicity and long, distinguished history, the C programming language is actually a surprisingly tangled beast, especially when it comes to reminiscence management. In C, any correctly aligned pointer-size bit pattern in reminiscence can potentially exist used as an address; the language explicitly allows casting from void * to a typed pointer, and vice versa. Objective-C, as a superset of C, inherits these charming properties. In exchange for this sacrifice, Objective-C code can exist compiled alongside unpretentious C code and can link to C libraries with ease.

    This means that the runtime garbage collector is expected to traverse reminiscence allocated by an arbitrary conglomeration of Objective-C and unpretentious conventional C code and Make the rectify decision—every time—about what reminiscence may safely exist collected. Apple's Objective-C garbage collection is a global switch. It can't exist enabled just for the clean, object-oriented Objective-C code that application developers write; it applies to the entire process, including replete the frameworks that the application links to.

    It seems sensible for garbage collection to recall a hands-off approach to any reminiscence allocated outside Objective-C's gated object-oriented community. Unfortunately, reminiscence allocated "the old-fashioned way" in unpretentious C code routinely makes its way into the world of Objective-C, and vice versa. In theory, replete such code could exist annotated in such a way that it works correctly with garbage collection. In practice, Mac OS X contains way too much code—much of it not written by Apple—to exist able to properly vet every line of it to ensure that a runtime garbage collector has enough information to Make the right decisions in every case.

    And, in fact, despite Apple's bold claims of readiness, there enjoy been and continue to exist cases where even code within Apple's own frameworks can confuse the Objective-C garbage collector. These kinds of bugs are particularly insidious because they may only manifest themselves when the collector runs within a certain window of time. The garbage collection compatibility outlook for third-party libraries is even more grim.

    Long chronicle short: garbage collection for Objective-C is out. (It's noiseless supported in Lion, but I wouldn't matter on Apple putting a tremendous amount of exertion into it going forward. And don't exist surprised if it goes the way of Rosetta in a few years.) In its place, Apple has created something called Automatic Reference Counting, or ARC for short. But to understand ARC, you should first understand how reminiscence management in Cocoa has traditionally worked.

    Cocoa reminiscence management

    Cocoa uses a reminiscence management technique called reference counting. Each protest has a reference matter associated with it. When some portion of an application takes ownership of an object, it increments the object's reference matter by sending it a retain message. When it's done with the object, it decrements the reference matter by sending a release message to the object. When an object's reference matter is zero, it is deallocated.

    This allows a solitary protest to exist used by several different parts of the application, each of which is liable for bookending its exhaust of the protest with retain and release messages. If retain is sent to an protest more times than release, then its reference matter will never compass zero and its reminiscence will never exist freed. This is called a reminiscence leak. If release is sent more times than retain, then a release message sent after the object's reference matter has reached zero will find itself looking at the region of reminiscence formerly occupied by the object, which may now accommodate anything at all. A crash usually ensues.

    Finally, there's the autorelease message which means "release, but later." When an protest is sent an autorelease message, it's added to the current "autorelease pool." When that pool is drained, replete objects in it are sent one release message for each time they were added to the pool. (An protest may exist added to the selfsame autorelease pool multiple times.) Cocoa applications enjoy an autorelease pool that's drained at the linger of each event loop, but recent pools can exist created locally by the programmer.

    Simple, right? Just Make certain your retain and release/autorelease messages are balanced and you're golden. But as straightforward as it is conceptually, it's actually surprisingly effortless to Get wrong. Experienced Cocoa programmers will narrate you that retain/release reminiscence management eventually becomes second-nature—and it does—but programmers are only human. Accurately tracking the lifecycle of replete objects in a big application starts to shove the limits of human mental capacity. To help, Apple provides sophisticated developer tools for tracking reminiscence allocations and hunting down leaks.

    But education and tools only scramble so far. Cocoa experts may not view retain/release reminiscence management as a problem, but Apple is looking towards the future, towards recent developers. Other mobile and desktop platforms don't require this sort of manual reminiscence management in their top-level application frameworks. Based on Apple's past efforts with garbage collection, it seems lucid that Apple believes it would exist better for the platform if developers didn't enjoy to manually manage memory. Now, finally, Apple believes it has create a solution that it can really Get behind.

    Enter ARC

    To understand how ARC works, start by picturing a traditional Objective-C source code file written by an expert Cocoa programmer. The retain, release, and autorelease messages are sent in replete the right places and are in perfect balance.

    Now imagine editing that source code file, removing every instance of the retain, release, and autorelease messages, and changing a solitary build setting in Xcode that instructs the compiler to achieve replete the confiscate reminiscence management calls back into your program when the source code is compiled. That's ARC. It's just what the appellation says: traditional Cocoa reference counting, done automatically.

    Xcode's ARC setting (highlight added)Xcode's ARC setting (highlight added)

    Before explaining how ARC does this, it's famous to understand what ARC does not do. First, ARC does not impose a recent runtime reminiscence model. Code compiled under ARC uses the selfsame reminiscence model as unpretentious C or non-ARC Objective-C code, and can exist linked to replete the selfsame libraries. Second, ARC provides automatic reminiscence management for Objective-C objects only (though note that blocks likewise happen to exist Objective-C objects under the covers). reminiscence allocated in any other way is not touched and must noiseless exist managed manually. (The selfsame goes for other resources enjoy file handles and sockets.) Finally, ARC is not garbage collection. There is no process that scans the reminiscence image of a running application looking for reminiscence to deallocate. Everything ARC does happens at compile time.

    What ARC does at compile time is not magic. There is no abysmal synthetic intelligence at drudgery here. ARC doesn't even exhaust LLVM's sophisticated static analyzer to device out where to achieve the retains and releases. The static analyzer takes a long time to run—too long to exist a mandatory portion of the build process; it can likewise bear untrue positives. That's fine for a instrument meant to detect feasible bugs, but reliable reminiscence management requires certainty.

    What allows ARC to drudgery is the selfsame thing that enables people to (eventually) become expert Cocoa programmers: conventions. Cocoa has rules about the transfer of ownership that takes situation during common operations enjoy getting or setting an protest attribute, initializing an object, or making a mutable copy. Furthermore, the methods that implement these operations succeed a set of naming conventions. ARC knows replete these rules and uses them to pick when to retain and when to release.

    In fact, ARC follows the rules in a more academic manner than any human ever would, bracketing every operation that could possibly exist influenced by protest ownership with the confiscate retain and release messages. This can bear a huge number of reminiscence management operations. Luckily, Apple has an excellent optimizing compiler called Clang (since rechristened by Apple's marketing geniuses as the Apple LLVM Compiler 3.0). Clang sweeps through this sea of mechanically generated code, detecting and eliminating redundancies until what remains looks a lot enjoy what a human would enjoy written.

    Conventions were made to exist broken, of course. But what ARC lacks in semantic sophistication it makes up for in predictability and speed, speed, speed. In cases where the human really does know best, ARC can exist told exactly what to attain thanks to a comprehensive set of recent attributes and macros that allow the developer to annotate variables, data structures, methods, and parameters with specific instructions for ARC. But the understanding behind ARC is that these exceptions should exist rare.

    To ensure that ARC can attain what it's designed to attain in a rectify manner, a few additional language restrictions enjoy been added. Most of them are esoteric, existing on the boundaries between Objective-C and unpretentious C code (e.g., C structs and unions are not allowed to accommodate references to Objective-C objects). Compatibility with existing C code is one of Objective-C's greatest strengths. But since ARC is a per-compilation-unit feature and ARC and non-ARC code can exist mixed freely, these recent language restrictions Make ARC more reliable without compromising interoperability.

    ARC versus garbage collection

    Apple's Objective-C garbage collection came with some drawbacks. As alluded to earlier, the programmer has dinky control over when the garbage collector will run, making protest reclamation non-deterministic. A garbage-collected application with a reminiscence management bug may crash or not depending on when the collector actually runs. Since garbage collection only runs periodically, the "garbage" (memory) may start to pile up in between runs. This can augment the so-called "high water mark" of an application. Finally, the garbage collection process itself can tamper with the execution of the application.

    Even on a multicore CPU where the collector can race on a sever thread, it must noiseless interact with the running application's reminiscence image, sometimes (briefly) blocking its progress while it cleans up the garbage. On relatively weak, often single-threaded mobile CPUs, this interference can manifest itself as stutters or glitches in the user interface.

    ARC offers a very different value proposition. To start, it suffers from None of the disadvantages of Objective-C's runtime garbage collection. ARC is deterministic; replete the reminiscence management code is baked into the executable and does not change at runtime. reminiscence management is integrated directly into the program flow, rather than being done in batches periodically. This prevents execution stalls, and it can likewise reduce the tall water mark.

    Most forms of automatic reminiscence management incur some kindly of performance hit. Not ARC. To Make up for any feasible augment in the number of reminiscence management messages generated by ARC, retain and release is 2.5 times faster in Lion; autorelease pools are 6 times faster; and to top it off, established Objective-C message sending is 33 percent faster. Furthermore, since it's the compiler, not the programmer, inserting the reminiscence management code, the generated retain and release code does not enjoy to peek exactly enjoy a established compiled Objective-C message send. The compiler has a much more intimate relationship with the Objective-C runtime, and can therefore optimize those operations in ways that a programmer cannot (well, should not, anyway).

    Finally, unlike garbage collection, ARC is a per-compilation-unit setting. Using ARC in your application does not sordid that every library you link to will likewise race under ARC. This means that you don't enjoy to worry about whether or not every solitary one of Apple's libraries works correctly under ARC. Only Apple has to worry about that, and it can pick on a case-by-case basis which should exist compiled with ARC and which should not. ARC and non-ARC code can exist mixed freely.

    Objective-C garbage collection does, however, enjoy one leg up on ARC. The garbage collector can detect and correctly reclaim protest graphs with cycles in them. Under reference counting, if protest A has a reference to protest B, and protest B has a reference to protest A, then both A and B enjoy a reference matter of at least one. Even if no other protest in the entire application has a reference to A or B, they will not exist deallocated when running under ARC because they both, eternally, enjoy nonzero reference counts.

    ARC requires the programmer to explicitly exploit these situations, either manually breaking the cycles by removing one or more references or by using another Objective-C feature called "zeroing frail references." (A frail reference is a reference that doesn't contribute to an object's reference count.) For example, in a typical parent/child relationship, the parent might enjoy a reference to the child and the child would enjoy a frail reference back to the parent. When the application no longer references the parent or child, the child will enjoy a reference matter of 1 (the parent noiseless references it) but the parent will enjoy a reference matter of 0 and will therefore exist deallocated. That then leaves the child with a reference matter of 0, and it will exist deallocated. Et voilà, no reminiscence leak.

    The "zeroing" portion means that frail references will exist set to nil when the protest they reference is deallocated. (Under ARC, replete protest pointers are initially set to zero.) Under established circumstances, an protest shouldn't exist deallocated if there are noiseless outstanding references to it. But since frail references don't contribute to an object's reference count, an protest can exist deallocated when there are outstanding frail references to it. When this happens, the automatic zeroing of the outstanding frail references prevents them from becoming dangling pointers. (In Objective-C, sending a message to nil is a no-op.)

    ARC versus the world

    Now they approach to the 65,536 byte question. Does ARC achieve Apple back on an even footing with its competitors when it comes to programming language abstraction? The answer, I'm afraid, is no. ARC takes trust of almost replete the mundane Objective-C reminiscence management tasks, but everything outside of Objective-C remains as it was. Furthermore, ARC does very dinky to address the other pillar of modern, high-level programming: reminiscence safety.

    For replete its auto-zeroing pointers and automatic protest deallocation, ARC-enabled Objective-C is noiseless a superset of C, and developers remain just a solitary infamous pointer dereference away from scribbling replete over their application's reminiscence space. This is a far weep from the garbage collected, cycle-detecting, memory-safe, and sometimes even dynamically typed languages available on other platforms, both mobile and desktop.

    This brings us back to my six-year-old set of premises: that programming language abstraction increases over time; that Apple's competitors exhaust languages that enjoy a higher plane of abstraction than Objective-C; and that Apple has yet to accountfor how or when it's going to nigh the gap. ARC may not achieve parity with the likes of Java, C#, and JavaScript, but it does, finally, provide some insight into how Apple plans to withhold its progress platform technologically competitive.

    The first thing ARC reveals is that Apple does correspond that there's a gap to exist closed. It chose to attack the lowest-hanging fruit first, the one thing about Apple's progress environment most likely to stand out as primitive and backwards to programmers coming from other platforms or even fresh out of school: manual reminiscence management. But while doing so, Apple was not willing to sacrifice any of Objective-C's historic strengths. Objective-C with ARC retains its compatibility with existing code and libraries and remains lean, mean, and as fleet as ever—faster, in some cases.

    Right now, Apple seems committed to these two platform pillars: compatibility and performance. Compatibility is essential to protect Apple's considerable investment in its APIs and developer tools. (Apple even went so far as to enable ARC to drudgery on Snow Leopard, albeit without the zeroing frail references feature.) Performance remains a competitive handicap for Apple's mobile devices, not just in terms of interface responsiveness and stutter-free animations, but likewise in power usage. Those runtime garbage collectors and virtual machines on other platforms can thrash caches and withhold more mobile CPUs cores working longer and harder.

    Apple may enjoy danced with runtime garbage collection, but it's going home with compile-time automation. There is no clearer indicator of Apple's commitment than the fact that ARC is now the default for replete recent projects created in Xcode; garbage collection never was.

    The most intriguing aspect of ARC is what it might portend for Apple's future. ARC shows that Apple is willing to add restrictions to the language in exchange for developer convenience and safety. It likewise implies that Apple believes that compile-time automation and optimization is, if not preferable to, then at least as Good as the runtime solutions available elsewhere, especially on mobile platforms.

    One thing that Apple does not apparently envision in its platforms' future is a traditional virtual machine, for replete the reasons previously stated: performance, compatibility, and power usage. Runtime garbage collection is similarly off the table for now. (It's not that Apple believes that garbage collection necessarily precludes much performance; it's just a indigent fortunate for Objective-C and Cocoa.)

    What Apple has instead is a cutting-edge traditional compiler built on a framework that supports many of the selfsame concepts (e.g., bytecode, JIT), but at a lower level.

    Putting it replete together, it's not hard to imagine a future in which Apple's developers write code in a memory-managed, memory-safe language that incorporates only the highest-level aspects of Objective-C, but remains binary compatible with Objective-C libraries and code. This approach has been described as "Objective-C without the C," and that's not far off. They could arrive at this destination through a chain of incremental changes—ARC being the latest—which slowly add optional (but recommended) features and restrictions to Objective-C, only the last of which would exist touted as introducing a "new language."

    Apple has invested a lot of time and manpower in getting off of gcc and onto a faster, more capable compiler. Now that the transition is over, Apple's attention can whirl towards adding innovative features. The next few years of WWDC could exist interesting.

    The state of the file system

    The file system implementation is not something most Mac users think about—nor should they. But enjoy any other portion of an operating system, there's some expectation that it will ameliorate over time. And enjoy any piece of technology, there comes a point where incremental improvements are no longer enough and a fresh start is required.

    Mac OS X itself was one such fresh start, albeit one derived from an existing product that was only slightly newer than the one it was replacing. But Mac OS X's file system, HFS+, was carried over from classic Mac OS directly into Mac OS X. It didn't Get a fresh start when the comfort of the OS did.

    Hopes were tall for a recent file system back in 2006 when Apple publicly declared its interest in a port of Sun's innovative ZFS file system. The next year, Sun's CEO announced that ZFS would exist portion of Mac OS X 10.5 Leopard—obviously without consulting Apple first.

    It didn't happen; Leopard shipped with HFS+. Two years after that, in 2009, Apple itself listed ZFS as a feature of Snow Leopard Server, only to later remove replete references to ZFS from its Snow Leopard webpages. A few months later, Apple shut down its open-source project to port ZFS to Mac OS X.

    In the meantime, HFS+ has certainly been incrementally improved. Apple has added champion for metadata journaling, case sensitivity, access control lists, and arbitrarily extensible metadata. None of these additions changed the basic design of the file system, however. HFS+ is thirteen years old, and is itself an extension of the HFS file system which is more than twenty-five years old. The state of the technique in file system design has advanced a lot since 1985.

    But again, most people don't disburse much time thinking about the file system. They think about files and folders, sure, but not the software that manages how the individual bytes are arranged on the storage device. My longstanding preoccupation with the nitty-gritty of file storage has often been met with indifference or even derision. "Who cares about a recent file system?" question the scoffers. "HFS+ works fine. It stores and retrieves my files just fine. What's the problem?"

    In response to this sentiment, I'd enjoy to proffer some concrete reasons why HFS+ is long overdue for replacement. I believe that Apple understands these problems better than anyone, but that a chain of luckless events has resulted in its next-generation operating system being hamstrung with a previous-generation file system for the past decade. Before discussing whether or not Lion makes any progress in this area, let's recall a hard peek at their conventional friend, HFS+.

    What's wrong with HFS+

    Software is written with certain target hardware in mind. When HFS was created, the top-of-the-line Macintosh came with an 800K floppy drive, the "high-end" storage offered by Apple was a 20MB hard drive the size of a lunchbox, and the CPU was from the Motorola 68000 family. Thirteen years later, HFS+ replaced HFS, the floppy disks were 1.44MB, and Apple's hard drives topped out around 6GB. withhold this context in mind as they deem the following details of HFS+'s implementation.

    When searching for unused nodes in a b-tree file, Apple's HFS+ implementation processes the data 16 bits at a time. Why? Presumably because Motorola's 68000 processor natively supports 16-bit operations. Modern Mac CPUs enjoy registers that are up to 256 bits wide.

    All HFS+ file system metadata read from the disk must exist byte swapped because it's stored in big-endian form. The Intel CPUs that Macs exhaust today are little-endian; Motorola 68K and PowerPC processors are big-endian. (The performance cost of this is negligible; it's mostly just silly.)

    The time resolution for HFS+ file dates is only one second. That may enjoy been enough a few decades ago when computers and disks were slower, but today, many thousands of file system operations (and many billions of CPU cycles) can exist executed in a second. Modern file systems enjoy up to nanosecond precision on their file dates.

    File system metadata structures in HFS+ enjoy global locks. Only one process can update the file system at a time. This is an embarrassment in an age of preemptive multitasking and 16-core CPUs. Modern file systems enjoy ZFS allow multiple simultaneous updates, even to files that are in the selfsame directory.

    The total number of blocks in an HFS+ volume is stored in a 32-bit value. With 4KB blocks, this allows for a maximum disk size of 17TB. That may sound huge to you now, but deem that it's only a sixfold augment over what they enjoy today, and today's largest hard drives are, in turn, a sixfold augment over what they had in 2005. (Apple can, of course, augment the obscure size from 4KB to, say, 8KB, but you can only play that game so long.)

    HFS+ lacks sparse file support, which allows space to exist allocated only as needed in big files. think about an application that creates a 1GB database file, then writes a few bytes at the start as a header and a few bytes at the linger as a footer. On HFS+, slightly less than a gigabyte of zeros would enjoy to exist written to disk to Make that happen. On a modern file system with sparse file support, only a few bytes would exist written to disk.

    Concurrency, metadata written in the rectify byte order, sub-second date precision, champion for massive volume sizes, and sparse file champion are replete common features of Unix file systems. Mac OS X, of course, is built on a Unix foundation. When HFS+ was ported from classic Mac OS to Mac OS X, it needed to exist extended to champion some minimum set of features that are expected from Unix file systems.

    Some of those features were an effortless fit, but others were very difficult to add to the file system without breaking backwards compatibility. One particularly scary sample is the implementation of hard links on HFS+. To withhold track of hard links, HFS+ creates a sever file for each hard link inside a hidden directory at the root plane of the volume. Hidden directories are kindly of creepy to originate with, but the actual scare comes when you bethink that Time Machine is implemented using hard links to avoid unnecessary data duplication.

    Listing the contents of this hidden directory (named "HFS+ Private Data", but with a bunch of non-printing characters preceding the "H") on my Time Machine backup volume reveals that it contains 573,127 files. B-trees or no b-trees, over half a million files in a solitary directory makes me nervous.

    That feeling is compounded by the most glaring omission in HFS+—and, to exist fair, many other file systems as well. HFS+ does not concern itself with data integrity. The underlying hardware is trusted implicitly. If a few bits or bytes Get flipped one way or the other by the hardware, HFS+ won't notice. This applies to both metadata and the file data itself.

    Data corruption in file system metadata structures can render a directory or an entire disk unreadable. (For a double-whammy, think about corruption that affects the "HFS+ Private Data" directory where every solitary hard link file on a Time Machine volume is stored.) Corruption in file data is arguably worse because it's much more likely to scramble undetected. Over time, it can propagate into replete your backups. When it's finally discovered, perhaps years later when looking at conventional baby pictures, it's too late to attain anything about it.

    But how often does data corruption actually occur? The reply seems to exist "more often than you'd think." Here's an excerpt from a 2010 academic paper on data integrity:

    In a recent study of 1.53 million disk drives over 41 months, Bairavasundaram et al. demonstrate that more than 400,000 blocks had checksum mismatches, 8 percent of which were discovered during RAID reconstruction, creating the possibility of actual data loss. They likewise create that nearline disks develop checksum mismatches an order of magnitude more often than enterprise class disk drives.

    Read the whole paper (PDF) for more detail and references. (Here's another sample [PDF] from CERN, and the data integrity section of the ZFS Wikipedia entry contains more information and links.)

    Most of these studies concern themselves with enterprise-scale deployments, but personal storage exhaust today is where enterprise storage was only a few years ago (in terms of capacity, if not throughput). And withhold in mind that replete of these issues only Get worse as the data volume goes up—which it inevitably does, year after year.

    It's rapidly becoming inexcusable for the storage systems they entrust with some of their most precious possessions—something we're actively encouraged to attain by Apple itself—to recall such a cavalier approach to data integrity. The worst portion is that there's dinky a user can attain to Make up for this technological gap; backups only serve to silently spread data corruption.

    I'll desist here, but attain note that I haven't even gotten to many of the other headliner features of modern file systems: constant-time snapshots, transactional updates, data deduplication, and on and on. HFS+ has served Apple well, and probably for far longer than its designers ever imagined it would. But enjoy replete the other Apple-related products and technologies that fortunate this description (e.g., classic Mac OS, Carbon, PowerPC), there comes a time when things once treasured must pass from this world.

    File system changes in Lion

    Finally, they approach to the heart of the matter. In Lion, what does Apple announce to the god of file system death? "Not today."

    That's right, the default and only file system on which you can install Lion is their conventional friend, HFS+. As famed earlier, I'm certain Apple is acutely cognizant of HFS+'s shortcomings and would matter its inability to field a successor among its (rare) recent failings as steward of the platform. But it looks enjoy it will recall a while longer for Apple's file system roadmap to Get back on track after the ZFS near-miss.

    Nevertheless, there are some file system changes in Lion—some significant ones, in fact. The biggest is the introduction of Apple's first actual crack at creating a logical volume manager: Core Storage.

    In earlier versions of Mac OS X (or classic Mac OS, for that matter), a solitary physical disk could accommodate one or more volumes. That is, connecting the disk to a Mac would antecedent one or more recent hard drive icons to issue in the Finder. By far, the most common case is to enjoy just one volume on each physical hard drive. But Mac users with more tangled needs (e.g., people who enjoy to install many different versions of the operating system for testing or review purposes) recall replete handicap of the faculty to carve up a solitary physical disk into multiple independent volumes.

    The role of HFS+ in this fuse is revealed by Apple's nomenclature. HFS+ is a "volume format." It stands to judgement that there must then exist something above HFS+ liable for managing the multiple volumes that may exist on a solitary disk, in the selfsame way that HFS+ manages the multiple files and folders that exist within a solitary volume. And so there is. Apple supports several varieties of what it calls "partition maps." ("Partitions" are the regions of a solitary disk carved out for volumes, one volume per partition. Apple's currently favored partition map is the GUID flavor.)

    Logical volume management is a broad term that usually means allowing more flexible relationships between disks and volumes than traditionally provided by partition maps. In the case of Apple's Core Storage, the key recent feature is the faculty for a solitary volume to span multiple physical disks.

    Somewhat obscuring this is a raft of recent terminology to record the recent layers of the storage stack. At the very top plane is the logical Volume Group, which may accommodate one or more Physical Volumes. A Physical Volume provides storage; it may exist a solitary physical disk, a disk image file, or even a RAID device. A logical Volume Group exports zero or more logical Volume Families. A logical Volume Family contains one or more logical Volumes, each of which presents a blank canvas onto which—finally!—a volume format enjoy HFS+ may reside.

    Got replete that? Don't worry if you haven't. The only thing you exigency to understand for now is that Core Storage provides a much richer set of abstractions above the volume format. The next question is obvious: what does Lion attain with Core Storage?

    If you're entertaining visions of ZFS-style pooled storage, let me nip that in the bud. There is no friendly GUI for creating disk-spanning volumes, and the command-line tools provided are rudimentary and, in my brief testing, don't seem to champion replete of the features ostensibly enabled by Core Storage.

    Core Storage's purpose in Lion is discreetly hidden in the logical Volume Family tier of the layer cake. logical Volume Families don't just export logical Volumes, they likewise accommodate properties that apply to them. One such set of properties in Lion enables replete disk encryption.

    Though Apple is using the appellation FileVault to brand this feature, it has absolutely nothing to attain with the feature of the selfsame appellation from earlier versions of Mac OS X. The earlier incarnation of FileVault encrypted an individual user's home directory by storing it in an encrypted disk image file. This presented replete sorts of complications to common operations, and FileVault earned a horrible reputation for indigent compatibility with existing software (including Apple's own, enjoy Time Machine).

    Lion's FileVault doesn't just encrypt users' home directories, and it doesn't exhaust encrypted disk image files. Instead, it's Apple's implementation of whole disk encryption. This means that every byte of data that makes up the volume is encrypted. Furthermore, this encryption is completely transparent to replete software (including the implementation of HFS+ itself) because it takes situation at a layer above the volume format—a layer that application software does not view at all.

    Having used a third-party whole-disk encryption product for years, I can narrate you that this approach works amazingly well. It really is completely transparent, and the only compatibility issues I've had involved operating system upgrades. (When affecting from Leopard to Snow Leopard, a recent version of the disk encryption software was required. Presumably, this will not exist a problem now that the feature is built into the OS.)

    Enabling whole-disk encryption is effortless in Lion. The FileVault tab in the Security & Privacy preference pane carefully guides a user through the process, presenting lucid explanations along with an extremely generous dose of caution.

    FileVault whole-disk encryptionFileVault whole-disk encryption

    Each user who will exist able to decrypt the drive must enter their password to attain so. Next, an auto-generated "recovery key" is presented, along with a suggestion to "make a copy and store it in a safe place." This is a last go in case a user forgets his or her account password. More dire warnings about data loss accompany this information.

    FileVault recovery key: your last best hopeFileVault recovery key: your last best hope

    Will people really write down that long recovery key and store it in a safe place? Apple has its doubts, it seems, because the next screen asks if you'd enjoy Apple to store the recovery key for you. There is no default choice for this question, which is exactly right, as far as I'm concerned. Most users probably should allow Apple to store their recovery key, but making that the default might exist seen as an overreach by geeks and security nerds.

    If you pick to reliance Apple, you must enter answers to three personal questions of your choice. The dialog claims that no one, not even Apple itself, can access your recovery password without the answers to these questions. We've heard claims enjoy this before, but I'm inclined to believe that Apple has scholarly from the mistakes of others.

    Recovery key escrow: waiton Apple waiton youRecovery key escrow: waiton Apple waiton you

    Finally, Apple insists that a recovery partition exist present on the disk that's about to exist encrypted. If it isn't, and if one can't exist created (e.g., because it uses the wrong kindly of partition map, or because doing so would shift a Boot Camp partition to the fourth position, making it unbootable), encryption won't exist allowed to proceed. (It's kindly of annoying that this check is only made at the very linger of the process.)

    Assuming a recovery partition exists or can exist created, a restart is required to enable encryption. Upon reboot, a screen that looks a lot enjoy the Lion login screen (but only containing the users who are allowed to decrypt the volume) appears instantly. Select a user and enter the rectify login password and the actual boot process begins. Even if auto-login is disabled, you will boot directly into the account whose password was just entered.

    Revisiting the FileVault preference pane shows an rate of the time remaining before the encryption process is complete. Encryption happens transparently in the background, which is a Good thing because it takes a long time. While it's running, you can exhaust applications, logout, reboot, and generally exhaust your Mac as you normally would without perturbing the encryption process.

    If any users on the system are unable to decrypt the disk, they can exist allowed to attain so by having them enter their login password.

    Enable more users to access the encrypted diskEnable more users to access the encrypted disk

    The output of the diskutil list command now looks a bit insane (compare to earlier):

    /dev/disk1 #: kind appellation SIZE IDENTIFIER 0: GUID_partition_scheme *250.1 GB disk1 1: EFI 209.7 MB disk1s1 2: Apple_CoreStorage 124.5 GB disk1s2 3: Apple_Boot Recovery HD 654.6 MB disk1s3 4: Apple_HFS Timex 124.6 GB disk1s4 /dev/disk2 #: kind appellation SIZE IDENTIFIER 0: Apple_HFS Lion Ex *124.2 GB disk2

    What once appeared to the OS as a solitary disk device now registers as two. One contains the two non-encrypted volumes (Recovery HD and Timex) plus the recent Core Storage volume, and the other contains the mounted incarnation of the newly encrypted (well, encrypting, in this case) volume. Using the special Core Storage variant of the list command (diskutil cs list) reveals more detail, most of which should now Make sense after the earlier terminology review.

    CoreStorage logical volume groups (1 found) | +-- logical Volume Group 19566D89-E29A-4C6C-88FA-6B845EF1DEBB ========================================================= Name: Lion Ex Sequence: 1 Free Space: 0 B (0 B) | +-< Physical Volume 1A645A01-E149-48B4-8C79-5FD3E20384F1 | ---------------------------------------------------- | Index: 0 | Disk: disk1s2 | Status: Online | Size: 124509331456 B (124.5 GB) | +-> logical Volume Family 58B532AA-B265-4AC7-B53B-12BB039D97B2 ---------------------------------------------------------- Sequence: 9 Encryption Status: Unlocked Encryption Type: AES-XTS Encryption Context: Present Conversion Status: Converting Has Encrypted Extents: Yes Conversion Direction: forward | +-> logical Volume 8A7ACC28-321B-4653-8E85-94CAF047D1DE --------------------------------------------------- Disk: disk2 Status: Online Sequence: 4 Size (Total): 124190560256 B (124.2 GB) Size (Converted): 2539913216 B (2.5 GB) Revertible: Yes (unlock and decryption required) LV Name: Lion Ex Volume Name: Lion Ex Content Hint: Apple_HFS

    Lion doesn't Make encrypting disks other than the boot disk particularly easy. The Disk Utility application can remove encryption from a volume, change a volume's encryption password, or reformat a volume with encryption enabled (deleting replete the data currently on the volume in the process), but there is no option to transparently encrypt a volume without erasing it.

    Command-line tools to the rescue: diskutil will happily attempt to encrypt any volume you point it at, without erasing it first. Actually, the process is to metamorphose it to a Core Storage volume which may optionally comprehend encryption. Let's encrypt the Timex volume, shown as disk1s4 in the earlier diskutil list output.

    % diskutil cs metamorphose disk1s4 -passphrase mysecret Started CoreStorage operation on disk1s4 Timex Resizing disk to fortunate Core Storage headers Creating Core Storage logical Volume Group Attempting to unmount disk1s4 Switching disk1s4 to Core Storage Waiting for logical Volume to appear Mounting logical Volume Core Storage LVG UUID: B02B86AC-C487-43B3-8C2E-7918CE80ECDF Core Storage PV UUID: 76336EBE-A3B5-4E1E-98B4-8A6873746D86 Core Storage LV UUID: E1F2E293-9952-425E-A597-0954BA734102 Core Storage disk: disk3 Finished CoreStorage operation on disk1s4 Timex Encryption in progress; exhaust `diskutil coreStorage list` for status

    As the command output indicates, the volume is shrunk slightly to accommodate the Core Storage headers, then the layer cake of logical volume management components is created, at the very bottom of which is the recent logical volume. No restart is required to originate the process, which happens transparently in the background just enjoy the one initiated from the GUI. The diskutil cs list command now shows a pair of logical Volume Groups, each of which is declared to exist in the process of encryption. The exact amount of data encrypted and remaining to exist encrypted on each volume is likewise listed.

    CoreStorage logical volume groups (2 found) | +-- logical Volume Group 19566D89-E29A-4C6C-88FA-6B845EF1DEBB | ========================================================= | Name: Lion Ex | Sequence: 1 | Free Space: 0 B (0 B) | | | +-< Physical Volume 1A645A01-E149-48B4-8C79-5FD3E20384F1 | | ---------------------------------------------------- | | Index: 0 | | Disk: disk1s2 | | Status: Online | | Size: 124509331456 B (124.5 GB) | | | +-> logical Volume Family 58B532AA-B265-4AC7-B53B-12BB039D97B2 | ---------------------------------------------------------- | Sequence: 9 | Encryption Status: Unlocked | Encryption Type: AES-XTS | Encryption Context: Present | Conversion Status: Converting | Has Encrypted Extents: Yes | Conversion Direction: forward | | | +-> logical Volume 8A7ACC28-321B-4653-8E85-94CAF047D1DE | --------------------------------------------------- | Disk: disk2 | Status: Online | Sequence: 4 | Size (Total): 124190560256 B (124.2 GB) | Size (Converted): 16999776256 B (17.0 GB) | Revertible: Yes (unlock and decryption required) | LV Name: Lion Ex | Volume Name: Lion Ex | Content Hint: Apple_HFS | +-- logical Volume Group B02B86AC-C487-43B3-8C2E-7918CE80ECDF ========================================================= Name: Timex Sequence: 1 Free Space: 0 B (0 B) | +-< Physical Volume 76336EBE-A3B5-4E1E-98B4-8A6873746D86 | ---------------------------------------------------- | Index: 0 | Disk: disk1s4 | Status: Online | Size: 124551483392 B (124.6 GB) | +-> logical Volume Family F02B9A32-10DE-4BDF-9697-00CE1B6F1133 ---------------------------------------------------------- Sequence: 6 Encryption Status: Unlocked Encryption Type: AES-XTS Encryption Context: Present Conversion Status: Converting Has Encrypted Extents: Yes Conversion Direction: forward | +-> logical Volume E1F2E293-9952-425E-A597-0954BA734102 --------------------------------------------------- Disk: disk3 Status: Online Sequence: 4 Size (Total): 124232712192 B (124.2 GB) Size (Converted): 94633984 B (94.6 MB) Revertible: Yes (unlock and decryption required) LV Name: Timex Volume Name: Timex Content Hint: Apple_HFS

    At any point, the encryption process can exist reversed (using Disk Utility, the FileVault tab of the Security & Privacy preference pane, or the diskutil command-line program). The decryption process likewise happens in the background.

    Changing the encryption password for a disk does not require a lengthy decryption and re-encryption process. I assume FileVault in Lion works enjoy other whole disk encryption solutions in that what the password actually unlocks is the actual encryption key for the volume. Changing the encryption password only requires decrypting and re-encrypting the actual encryption key, which is tiny.

    The encryption features that Apple has chosen to provide access to in the GUI disclose a lot about the purpose of this feature. First, it's meant to exist completely transparent. The only change as far as the user is concerned is that the login screen appears to enjoy moved to the very beginning of the startup process. There is no sever password to remember; the user's login password decrypts the disk. The selfsame goes for every other user with an account on the system.

    Login passwords are only tied to a boot disk, however. Using login passwords to encrypt disks that may scramble from one Mac to another could lead to confusion. This partly explains why there's no GUI option for encrypting non-boot disks. The other portion of that conclusion is likely that FileVault is focused on mobile users. None of Apple's laptops enjoy more than one internal drive, and partitioning is rare and probably only done by users who likewise know enough to peek up the command-line utility to enable disk encryption on their non-boot volumes.

    Transparent encryption and decryption, perfect software compatibility, a friendly GUI with ample safety nets for non-geek users—what's not to love? Ah, I'm certain you're wondering about performance. replete forms of whole disk encryption profit from the current imbalance between CPU power and disk speed. In almost replete circumstances, the CPU in your Mac spends most of its time twiddling its thumbs with nothing to do. This is especially genuine for operations that involve a lot of disk access.

    Whole disk encryption takes handicap of this nearly omnipresent CPU cycle glut to sneak in the tiny chunks of drudgery it requires to encrypt and decrypt data from the disk. Apple likewise leverages the special-purpose AES instructions and hardware on Intel's newest CPUs, further reducing the CPU overhead. The linger result is that regular users will exist hard-pressed to notice any reduction in performance with encryption enabled. Based on my suffer with the feature in prerelease versions of Lion, I would strongly deem enabling it on any Mac laptop I draw to travel with.

    File system future

    Disk encryption that actually works, plus some basic logical volume management features—that's replete well and good. But where does this leave us on the file system front? Perhaps things are not as infamous as they seem. The following is replete speculation, but given Apple's information vacuum on replete things file-system-related, it's replete I've got for now.

    Core Storage is probably the most significant file system change in the history of Mac OS X. Let's think about what it does. Core Storage is liable for managing the chunks of data that Make up the individual logical volumes on a disk. To attain so, presumably it has a set of metadata structures for tracking allocated and free space and for remembering which chunks belong to which volumes.

    Now imagine that those chunks originate to shrink until they are the size of, say, individual files. And instead of volumes, imagine those file-sized chunks belonging to directories. Okay, it's a stretch, but again, it's replete they enjoy to scramble on. Assuming Apple is ecstatic with the way Core Storage turned out, it has effectively fielded its first brand-new code that performs some of the selfsame basic functions as a file system. Were Apple so inclined, it seems technically plausible, at least, that it could extend this drudgery into a recent in-house file system project.

    With ZFS out of the picture, Btrfs presumably eliminated due to its licensing, and future progress of ReiserFS uncertain, its hard to view where Apple will Get the modern file system that it so desperately needs other than by creating one itself.

    This is something I've been anticipating for years. I would enjoy certainly welcomed ZFS with open arms, but I was equally confident that Apple could create its own file system suited to its particular needs. That self-confidence remains, but the ZFS distraction may enjoy added years to the timetable.

    In the meantime, a few gallant souls are noiseless determined to bring ZFS to Mac OS X. I wish them luck, but I would much prefer a solution supported by the operating system vendor. Apple, the gauntlet has been thrown down; it's time to deliver.

    Document revisions

    Lion's modernized document model leans heavily on the faculty to manage multiple versions of a solitary document. Viewed solely through the user interface, it appears to exist magic. Unlike earlier incarnations of autosave, you won't view auto-generated files appearing and disappearing alongside the original document. But the data obviously has to exist stored somewhere, so where is it?

    Despite replete its flaws, the Mac OS X file system does enjoy several features that might exist useful for saving multiple versions of files. Version number metadata could exist stored in an extended attribute; the file data itself could conceivably exist stored in named forks; the existing invisibility metadata could exist used to veil the multiple versions.

    Although Apple has gotten religion regarding file system metadata in recent years, leaning heavily on extended attributes in the implementation of Time Machine, downloaded file quarantines, and access control lists, metadata holdovers from classic Mac OS are noiseless out of favor. If Spotlight's implementation has taught us anything, it's that today's Apple prefers to withhold things simple when it comes to the file system.

    Given replete of this, I wasn't surprised to find a /.DocumentRevisions-V100 directory lurking at the root plane of my boot drive, right alongside the /.Spotlight-V100 directory. Inside, you'll find an SQLite database file (/.DocumentRevisions-V100/db-V1/db.sqlite) containing tables for tracking files, the individual versions of those files (which Apple calls "generations"), and the storage location of the data. Here's the schema, for the curious.

    CREATE TABLE files ( file_row_id INTEGER PRIMARY KEY ASC, file_name TEXT, file_parent_id INTEGER, file_path TEXT, file_inode INTEGER, file_last_seen INTEGER NOT NULL DEFAULT 0, file_status INTEGER NOT NULL DEFAULT 1, file_storage_id INTEGER NOT NULL ); CREATE TABLE generations ( generation_id INTEGER PRIMARY KEY ASC, generation_storage_id INTEGER NOT NULL, generation_name TEXT NOT NULL, generation_client_id TEXT NOT NULL, generation_path TEXT UNIQUE, generation_options INTEGER NOT NULL DEFAULT 1, generation_status INTEGER NOT NULL DEFAULT 1, generation_add_time INTEGER NOT NULL DEFAULT 0, generation_size INTEGER NOT NULL DEFAULT 0 ); CREATE TABLE storage ( storage_id INTEGER PRIMARY KEY ASC AUTOINCREMENT, storage_options INTEGER NOT NULL DEFAULT 1, storage_status INTEGER NOT NULL DEFAULT 1 );

    Unlike Time Machine, Apple's file version storage system is not limited to saving a complete copy of each recent revision of a file. A second SQLite database (/.DocumentRevisions-V100/.cs/ChunkStoreDatabase) tracks the individual chunks that disagree from one revision of a file to another. (Examining its schema is left as an exercise for the reader. Just bethink to copy the database file to a recent location and race the sqlite3 program on the copy instead of the actual database, which will likely exist locked anyway.)

    Intelligently splitting files into chunks such that only a few chunks change from one revision to another is actually quite a difficult problem. deem a 10MB file, initially split into ten 1MB chunks. Now imagine that the next revision of the file simply adds two bytes to the very beginning of the file. Were the recent revision to exist naïvely split into ten equal-sized chunks, every chunk would exist different from replete previously created chunks, defeating the entire purpose of splitting files into chunks rather than saving complete copies every time.

    One technique Apple uses to deal with this problem is called Rabin fingerprinting. Chunks of the file are selected based on their content, rather than strictly based on their offset within the file. (The title of the research paper that introduced this technique, A Low-bandwidth Network File System, suggests that it might likewise exist useful for, say, a network-based file storage system. Hmmm.)

    This algorithm is not blindly applied to every file, however. The chunk storage engine knows about the internal structure of many common file formats (e.g., JPEG images, MPEG4 video, PDFs) and can intelligently chunk them based on this knowledge, separating headers and footers, finding the borders between internal elements, and so on. Unlike Spotlight, there doesn't issue to exist a plug-in system for adding specific champion for recent file types. Custom file types saved by third-party applications issue to exist left to the whims of Rabin fingerprinting.

    Very wee files (under, say, 32KB) issue not to exist chunked at all. Chunking is not guaranteed to happen immediately when a file is saved; it may happen at a later time. Very big files are generally split into larger pieces, preventing a situation where a 2GB file produces thousands of chunks. This whole demonstrate is race by a new, private GenerationalStorage.framework which includes a daemon named revisiond.

    (There's an appealing break here for a third-party developer to create an "unauthorized" application for browsing the contents of the generation store, perhaps even hacking in a recent context menu detail in the Finder for listing previous revisions of a selected file. An application enjoy this probably won't exist allowed into the Mac App Store, and it's likely to crash in the next OS revision, but it may noiseless find enough customers to exist worthwhile.)

    Apple's generational storage system is an appealing fuse of tried-and-true technologies (SQLite, daemons, unpretentious files and directories) with just enough cleverness to avoid being an undue tribulation to the system in operation. And remember, every solitary file created on the system is not automatically versioned in Lion. Generational storage is a feature that developers must explicitly use. I certain hope a lot of them attain so.

    Resolution independence

    Resolution independence has been "coming soon to Mac OS X" since 2005. The dream of drawing the selfsame interface elements at the selfsame visible size but with more pixels was so nigh in 2007 that they could tang it. Then Snow Leopard arrived and the Mac's interface scalability features actually regressed. Depressing.

    Meanwhile, Mac OS X's sibling operating system waltzed right into a high-resolution UI on its very first try. iOS's secret? Don't try to champion arbitrary scale factors, just champion one: double resolution. A 50x50-pixel square on a non-retina iPhone screen is exactly the selfsame size as a 100x100-pixel square on a retina display. Graphics that enjoy not been updated for the higher resolution are simply drawn with four-pixel squares in situation of each low-resolution pixel. replete dimensions are nice, even, integer multiples of each other. This is a perfect fortunate for physical screens which, of course, enjoy an integer number of pixels. Fractional measurements necessarily require grim compromises.

    Lion has taken the hint from its younger brother. arbitrary scalability is gone. In its situation is a solitary check box to enable "HiDPI" array modes. (This option is noiseless hidden away in the Quartz Debug application, so it's clearly not an end-user feature. But unlike replete previous incarnations of resolution independence, this one actually works.)

    HiDPI array modes on a 15-inch MacBook Pro (native resolution: 1440x900)HiDPI array modes on a 15-inch MacBook Pro (native resolution: 1440x900)

    After enabling HiDPI, recent array modes will become available. In the screenshot above, the 720x450 mode is half autochthonous screen dimensions, and the 640x400 mode is half the (non-native) 1280x800 setting. After selecting a HiDPI mode, everything is drawn with twice as many pixels as its non-HiDPI equivalent. Here's a screenshot featuring TextEdit, their accustomed interface scalability workhorse.

    TextEdit running in Lion's "HiDPI" mode Enlarge / TextEdit running in Lion's "HiDPI" mode

    It looks pretty good, right? The only flaws are the bitmap graphics that haven't been updated for HiDPI (look closely at the black triangles in the ruler). Unfortunately, there are a lot of these throughout the operating system and its bundled applications. But unlike in replete years past, the framework is finally there for third-party developers and Apple itself to finally Get their applications ready for a world in which 300-dpi desktop and laptop displays are more than just expensive curiosities.

    Unlike iOS, Mac OS X has to contend with a much wider variety of array sizes. Thus far, there has been no Mac equivalent of the iPhone 4, arriving with a double-density array and quickly selling so many units that it represents a significant portion of the installed base. Still, the ease with which iOS developers adapted to the retina array gives me self-confidence that this pixel-doubling approach can drudgery on the Mac as well. They just enjoy to wait a bit longer. By now, they should exist used to it.


    Thanks to the comprehensively revised user interface, most applications that ship with Lion peek new, but a few of them enjoy particularly significant changes. I'm not going to cover replete of them (you'll find more extensive screenshot galleries elsewhere), but here are some highlights.

    The Finder

    The Finder's transition from Carbon to Cocoa in Snow Leopard is starting to pay off in Lion. Several recent APIs added to Cocoa in Lion enjoy been adopted by the Finder. In days past, when the Finder was noiseless a Carbon application, it rarely got the latest and greatest features at the selfsame time as other bundled applications. No more.

    Cocoa in Lion gives developers more control over the image displayed when an detail is dragged from one situation to another. The Lion Finder uses this control to transform multi-item selections from the accustomed ghostly image of the source into a compressed, realigned, list-view representation. This transformation happens a instant or two after the drag begins.

    While this is a fine demonstration of a recent API, the suffer is a bit off-putting. Imagine taking a dish out of the dishwasher and then having it start flopping around enjoy a fish in your hand. This is a rare case of Apple losing sight of what's famous in real-time interaction design. Stability and responsiveness lead to comfort. A transformative animation (instability) that happens after a short dilatory (the appearance of unresponsiveness) does not Make for Good experience. I wonder how many novice users will instinctively release the mouse button and inadvertently terminate the drag operation the first time this animation is triggered.

    Search tokensSearch tokens

    The Finder likewise proudly demonstrates Lion's recent capsule-style search tokens. Free text can exist entered into the search field as usual, but a pop-up menu provides options to confine the scope of the search terms typed so far. The only two options available are "Filename" and "Everything," but the interface is fun and effortless to use, and the potential is there for much more sophistication. (For more tangled searches, the full-fledged Spotlight search with nested boolean logic remains in Lion.)

    By default, at the top of the Lion Finder's sidebar is the recent "All My Files" item. It's a canned search that finds replete documents in the user's home directory and displays the results in a flat list. The sidebar detail representing the computer as a whole, showing replete attached drives and connected servers, is noiseless available, but is not in the sidebar by default. The selfsame goes for the home directory item. The other predefined saved searches (e.g., Today, Yesterday, replete Images, etc.) are no longer available, though they can exist recreated manually.

    All My Files combined with a secondary filter, arranged by kindAll My Files combined with a secondary filter, arranged by kind

    The addition and prominence of "All My Files" is yet another vote of no-confidence in the user's faculty to understand and navigate the file system. If you've ever seen a Mac user try to navigate from the top plane of his hard drive down to his Documents folder, you can originate to understand the challenge Apple is up against here. The "All My Files" detail is just what the doctor ordered. In the increasingly rare cases when novices exhaust the Finder directly, rather than managing their data from within an application enjoy iTunes or iPhoto, replete they want to know is, "Where are replete my files?" Asked and answered.

    Expert users with thousands upon thousands of files will likely find the "All My Files" feature less useful. But if you desist thinking of it as a "location" and start thinking of it as a saved search to which you can apply additional filters with the toolbar's search field, it starts to Get more interesting. The only remaining barrier is performance, which does suffer as the number of files increases.

    All of the existing Finder view styles (icon, list, column, and cover flow) champion a recent "Arrange By" option which sorts items into groups. Each group has a header which "sticks" to the top of the window as the view is scrolled, until the last detail belonging to that group scrolls off the top of the list. The columns in the group headers are frustratingly un-configurable and can't exist individually resized. But those quibbles aside, the feature does add an appealing recent dimension to file browsing.

    A recent sort order has likewise been added to replete views: Date Added. This is an example order for the Downloads folder. Sorting by creation or modification date was always problematic for files that preserved their timestamps through the download process (e.g., zip-compressed Mac applications). This would antecedent "new" downloads to issue in unexpected positions in the list. I'm tempted to declare Date Added sorting as best recent feature in the Finder, but I'm fearful that might seem enjoy damning with faint praise.

    Aesthetically speaking, the Finder, enjoy the comfort of Lion, has been visited by the color vampire. The Finder sidebar doesn't even deference custom folder icons, showing them as generic gray folders instead. That seems a dinky tyrannical, even for Apple.

    The only Good folder is a gray folderThe only Good folder is a gray folder

    This paternalism extends to other aspects of the Finder, as well. Library folders are now invisible in the Finder, removing the temptation for novice users to scramble mucking around in directories they don't understand. The "Go to Folder…" menu command noiseless exists, so customer champion has some way, at least, to Get users there without resorting to a shell prompt. But existing champion documents that comprehend instructions and screenshots that await the Library folder to exist visible will enjoy to exist revised for Lion.

    View optionsView options

    The Finder's destructive fuse of browser and spatial behaviors remains in Lion. The tradition of subtly changing the rules that govern when, where, and how view state changes are applied and honored likewise continues. Just in case anyone thought they had finally figured out how the Snow Leopard Finder decides what view to demonstrate when displaying the contents of a folder in a particular window, Lion changes the rules again.

    The controls at the top of the view options palette now comprehend a mysterious sub-checkbox labelled "Browse in view," where view is the window's current view style. This appears to govern the view used when opening sub-folders from a window where the toolbar is visible, but a dinky experimentation will disclose that the setting is overridden by any "Always open in view" setting of a sub-folder. The linger result is the selfsame as it has ever been: an inscrutable system that users quickly give up any hope of understanding, resigning themselves to manually correcting view styles as needed during every interaction with the Finder.


    Apple's venerable Mail application gets a significant facelift in Lion. Once derided as one of the ugliest bundled applications, it's now been transformed into the classiest. (It doesn't harm that the competition has stumbled a bit.) The screenshot below is dominated by the glossy Apple promotional e-mail for Lion in the right-hand pane, but peek past it at the surrounding interface.

    Mail in Lion: a class act Enlarge / Mail in Lion: a class act

    Or rather, peek at how much of the surrounding interface isn't there. With the exception of the toolbar, this window is completely about the content. There are no external borders, only the barest hint of internal borders, and, as befitting a genuine Lion application, no visible scrollbars. The toolbar and quick-access button bar succeed the monochromatic Lion style while noiseless looking crisp. The cheeky red flag icon is likewise a nice touch.

    After years of unsupported hacks to add a three-pane wide-screen view to Mail, Apple has finally taken the hint and made it official. There's also, naturally, a full-screen mode.

    At last, widescreen three-pane Mail for all Enlarge / At last, widescreen three-pane Mail for all

    Like the Finder, Mail's search field supports Apple's snazzy recent search tokens. These provide the fastest way to attain medium-complexity searches that I've ever seen in any e-mail application. It's too infamous the search field is so narrow and doesn't expand to fill replete available space in the toolbar, however.

    The main viewing pane shows entire threads by default, with each message appearing as a sever virtual piece of paper. Mail aggressively collapses quoted text within messages, displaying an adorable accordion consequence upon expansion.

    Mail plays an accordion animation when expanding quoted text Enlarge / Mail plays an accordion animation when expanding quoted text

    Keyboard champion is excellent, allowing one-handed navigation for most common tasks. Expanding a thread and selecting a solitary message causes it to fill the right-hand pane, leaving behind the egotism that each message is actually a dinky piece of paper.

    Mail has become more capable, as well. Simple rich text editing capabilities enjoy finally been added. Mail is likewise even better about automatically setting up accounts for common services. The account setup screens just question for a name, e-mail address, and password, and will usually attain everything else for you, including (optionally) correctly configuring and integrating calendar and chat services that might exist associated with the e-mail account (e.g., Google Calendar and Talk).

    Rich text editing: let your font flag flyRich text editing: let your font flag fly

    If, enjoy me, you never seriously considered using any of the previous incarnations of Apple's Mail application, the version in Lion is definitely worth taking for a test drive—even if only as a haphazard to suffer an application that so thoroughly embraces the technology and aesthetic of the recent operating system.


    Besides adding champion for another crop of recent Web technologies (MathML, WOFF, CSS3 enhancements), the biggest change in Safari is its aforementioned exhaust of the recent WebKit2 rendering engine, which moves webpage rendering into a separate, low-privilege process. (Previous versions of Safari already isolated plug-ins in sever processes.) This change is invisible to the user, but it should provide an additional layer of protection against browser-based exploits.

    Safari's downloads window has been subsumed into the toolbar and is now displayed as an iPad-style popover. (This is a gauge control available to replete Cocoa applications in Lion.) When starting a download, an icon leaps from the point of the click into the downloads toolbar icon, which then displays a tiny progress bar. It's cute, informative for novices, and keeps the downloads window out of the way.

    Safari downloads in a popoverSafari downloads in a popover

    A wee eyeglasses icon in the bookmarks bar triggers Apple's recent Reading List feature, which saves the currently displayed webpage for later reading. This list of webpages is (or rather, will be) synchronized with Safari in iOS 5. Saved pages issue in the sidebar, accompanied by unattractively scaled favicons.

    Safari's Reading List: save webpages to read later. (High-resolution favicons recommended.)Safari's Reading List: save webpages to read later. (High-resolution favicons recommended.)

    Reading List follows in the moreorless dubious footsteps of other Apple products that enjoy clearly been "inspired," let's say, by common third-party services. As was the case when Safari added rudimentary champion for RSS, Reading List is unlikely to dislodge users who are already comfortable with their existing read-it-later service.

    But most people enjoy never even heard of such a thing. Reading List's prominent placement in Safari will certainly spread awareness. This could translate into more customers for competing services, even as Reading List takes the lion's share (sorry) of users.

    One last note on applications. The Finder, Mail, Safari, TextEdit, and even Terminal replete champion full-screen mode and restore replete their windows when relaunched. Apple is definitely trying to lead by example.

    Grab bag

    As this review winds down, let's relax with a dinky submerge into the conventional grab bag, a magnificient tradition where the smaller features Get their haphazard to shine. As in years past, Apple has its own, much snazzier and more complete incarnation. Check it out if you want a broader overview of Lion's recent features. These are just the ones that piqued my interest.

    System Preferences

    System Preferences enjoy been shuffled, consolidated, and renamed in every major releases of Mac OS X. Lion doesn't disappoint.

    The preference formerly known as Appearance is now called General, and it includes a checkbox to globally disable application state restoration. The Exposé & Spaces preference is now called Mission Control. Security becomes Security & Privacy. Accounts is now Users & Groups—a welcome change because, in my experience, most people don't know what an "account" is. Universal Access moves to the top row. And on and on. Dance, icons, dance!

    Your favorite system preferences: where are they today? Enlarge / Your favorite system preferences: where are they today?

    Individual preference icons can exist manually hidden by the user thanks to the recent "Customize…" menu item. (They will remain accessible from the View menu and via search.)

    Hide the preferences you're not interested in Enlarge / veil the preferences you're not interested in

    Click and hold on the "Show All" button to quickly jump from one preference to another via a drop-down menu. The View menu provided the selfsame functionality in Snow Leopard, but the "Show All" button is closer to where the cursor is likely to be.

    Take a direct flight to your next preference paneTake a direct flight to your next preference pane

    Perhaps surprisingly, the MobileMe preference remains. It's joined by the new, awkwardly named Mail, Contacts & Calendars preference which manages, well, mail, contacts, and calendar accounts for a variety of online services.

    Centralized online service account management Centralized online service account management

    This includes the ever-popular "Other" service, which leads to a set of more generic configuration screens for other protocols and applications.

    Manual configuration and more esoteric account typesManual configuration and more esoteric account types

    The trackpad preference pane allows some, but not replete of the recent gestures in Lion to exist configured in limited ways. For example, the Mission Control signal must always exist an upward swipe, but it can exhaust three or four fingers. replete of the gestures can exist disabled.

    Limited choices for signal
 configurationsLimited choices for signal configurations

    Finally, in case you needed any more evidence of Apple's newfound aversion to color in the Mac OS X interface, recall a peek at the recent time zone selection screen.

    Your world, replete
 silvery in the moonshineYour world, replete silvery in the moonshine Auto-correction

    Lion adds optional iOS-style auto-correction to the gauge Mac OS X text control. It looks and works just enjoy the iOS incarnation from which it's so clearly derived. enjoy the other spelling and grammar checking options, auto-correction can exist enabled on a per-document basis.

    I eagerly await the Compose Text Automatically optionI eagerly await the Compose Text Automatically option System-wide auto-correction: try to resist the press to tap the screenSystem-wide auto-correction: try to resist the press to tap the screen Mobile Time Machine

    Time Machine isn't much waiton when you're on the road with your laptop. None of Apple's portable Macs comprehend more than one internal drive, and making a Time Machine back up to another partition of the selfsame drive kindly of defeats the purpose.

    Lion includes a new, mostly invisible feature whereby Time Machine backups continue even when the backup volume is not mounted. This feature is only lively for laptops, which is a shame (though you can enable it on desktops using the tmutil command-line tool).

    The implementation is strange. The mtmfs (Mobile Time Machine file system) daemon runs an NFS server on localhost which is then mounted at /Volumes/MobileBackups. In it, you'll find the accustomed Backups.backupdb directory structure that Time Machine creates for its backups. The actual copies of recent and changed files—and only those files—are stored in /.MobileBackups by the mtmd daemon.

    This system provides some basic data protection for users on the go, beyond what's offered by applications that champion Lion's autosave APIs. Mobile Time Machine, enjoy regular Time Machine, tracks replete file changes, not just those made by certain applications.

    There is some obvious overlap between Mobile Time Machine and the generational store used to champion document versioning in Lion. Having two entirely sever storage locations and techniques for backup copies of files is suboptimal; perhaps the backends for these two features will merge in the future.

    Lock screen

    Lion's recent lock screen has been restyled to match the login screen, with options to unlock or switch users, and it comes with the selfsame subset of menu bar status icons visible in the top-right corner.

    Lion's recent
 lock screenLion's recent lock screen Emoji

    Lion adds Emoji champion to Mac OS X. So that happened.

    FACE WITH NO Good signal
 (U+1F645); MOON VIEWING CEREMONY (U+1F391); PILE OF POO (U+1F4A9)FACE WITH NO Good signal (U+1F645); MOON VIEWING CEREMONY (U+1F391); PILE OF POO (U+1F4A9) Terminal

    The Terminal application gets a few more graphical frills, sporting a recent parameter for window blur, with sever settings for lively and passive windows. The bundled Silver Aerogel theme demonstrates the effect.

    "I want to know what's behind my terminal window, but I don't want to know every detail.""I want to know what's behind my terminal window, but I don't want to know every detail."

    Terminal also—finally—supports 256 text colors with its recent xterm-256color terminal type. Users of terminal-based text editors will surely approve.

    About This Mac

    The System Profiler application has been renamed System Information and now includes a comprehensive, effortless to understand overview of the entire system. The copious links to champion documents, material preferences, and channels for feedback are fantastic. This will exist the recent go-to location for anyone trying to remotely diagnose a Mac problem. As before, it's most easily accessed by going to the Apple menu and selecting About This Mac, then clicking the "More Info…" button.

    Don't worry, geeks, the conventional System Profiler interface with its much more circumstantial technical information is noiseless accessible via the "System Report…" button. But it's likely that you'll rarely exigency the extra detail. recall a peek at what the recent screens offer.

    Tech specs never looked so goodTech specs never looked so good Did you know that your array has a manual?Did you know that your array has a manual? There certain seems to exist a lot of "other"There certain seems to exist a lot of "other" Unfilled RAM slots are sinful. I am ashamed.Unfilled RAM slots are sinful. I am ashamed. Five ways to Get supportFive ways to Get support An excellent executive summary of warranty information and service optionsAn excellent executive summary of warranty information and service options Recommendations Want an eBook or PDF copy? champion Ars and it's yours.

    Even at Ars Technica, a certain percentage of readers just want to know the bottom line about a recent operating system. Is this a Good release? Is it worth the price and the hassle of installing it? Excluding the first few dog-slow, feature-poor releases of Mac OS X, the reply to replete those questions has always been a resounding "yes." Lion continues this tradition, more than earning its $29 price with a raft of recent technologies and a substantially revised interface and suite of bundled applications.

    The gauge caveats apply about software and hardware compatibility. Don't just race out and upgrade your system as soon as you finish this review. Lion's digital distribution makes hasty upgrades even more likely. Patience! recall a few days—weeks, even—to research replete of your favorite applications and Make certain they replete race fine on Lion. If you're noiseless using some PowerPC applications, don't upgrade until you enjoy replaced them with Intel-native alternatives. And before you upgrade, back up, back up, back up.

    All that you can't leave behind

    Though the Lion appellation suggests the linger of something, the content of the operating system itself clearly marks the start of a recent journey. Seemingly emboldened by the success of iOS, Apple has taken a hatchet to decades of conventional wisdom about desktop operating systems.

    The selfsame thing happened ten years ago in an even more histrionic mode when Apple replaced classic Mac OS with Mac OS X. The recent operating system changed the rules on the desktop, wedding composited graphics, smooth animation, and photorealistic artwork to a solid Unix foundation. Apple tried to leave replete vestiges of its conventional operating system behind—the platinum appearance, the Apple menu, even the desktop itself—but eventually bowed to some demands of long-time Mac users. Lion's changes will no doubt meet with similar resistance from experienced Mac users, but I suspect Apple will remain unmoved this time around.

    In the selfsame way that Mac OS X so clearly showed the comfort of the industry what user interfaces would peek enjoy in the years to come, Apple's own iOS has now done the selfsame for its decade-old desktop operating system. iOS was less shocking to users because it appeared to approach from nothing, and the mobile operating system conventions it defied were ones that nobody liked anyway. The selfsame is not genuine on the desktop, where users cling enjoy victims of Stockholm syndrome to mechanics that enjoy harm them time and again.

    It may exist many years before even half of the applications on a typical Mac behave according to the design principles introduced in Lion. The transition era could exist ugly, especially compared to the effortless uniformity of iOS. In the meantime, let Apple's younger platform serve as a lighthouse in the storm. The Mac will always exist more capable than its mobile brethren, but that doesn't sordid that simple tasks must likewise exist harder on the Mac. Imagine being able to stick a computer neophyte in front of an iMac with the selfsame self-confidence that you might hand that neophyte an iPad today.

    The technical details of Apple's operating system that were once so famous that they practically defined its existence (e.g., reminiscence protection, preemptive multitasking) are now taken for granted. Mainstream reviews of software and hardware alike disburse far less time pondering technical specifications and implementation details than they did only a few years ago.

    This phenomenon extends even to the geekiest among us, those who didn't just skip to the conclusion of this review but actually read the entire thing. Fellow geeks, question yourselves, attain you know the clock hasten of the CPU in the device you're reading this on? attain you know how much RAM it has? What about the reminiscence bus hasten and width? Now deem what your answers might enjoy been ten years ago.

    Over the past decade, better technology has simply reduced the number of things that they exigency to trust about. Lion is better technology. It marks the point where Mac OS X releases desist being defined by what's been added. From now on, Mac OS X should exist judged by what's been removed.

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