On your desktop, multitasking means that any application or process can run at the same time as another. Technically, there’s no reason why the same can’t be done on a mobile device. However, from a more practical point-of-view, there is one good reason why you don’t want this: a running app uses energy that decreases your battery life. Running fewer apps means you can listen to music longer, make more phone calls, or call up Maps at the end of the day to find a place for dinner.

At the same time, there are certain types of app that must run in the background in order to be useful. Apple has identified three categories of apps:

• Audio – Apps that plays audible content while in the background. The poster child for this type of application is Pandora.
• VOIP – When you’re making or receiving phone calls over an Internet connection, you’re using a “Voice Over Internet Protocol” app that runs in the background. Skype is a good example.
• Location – Some applications need to run in the background so they can keep track of your current location. An app that logs GPS coordinates while you take a walk or run would need to do this.

Additionally, apps can tell iOS 4 that they need additional time to complete a task or want the user to be notified at a specific time. This lets apps finish a long download or pop up the little blue window like an incoming SMS message.

These simple rules cover a wide variety of situations, but there are still some cases that aren’t covered. The main shortcoming is with apps that need to periodically refresh data. Social networking apps, chat programs, news readers, and other utilities that check the Internet for changing data don’t fit into any of the above categories. Developers have proposed solutions to these problems, but there’s no solution for today’s software.

Part of the confusion with multitasking comes from Apple’s excellent implementation of “task switching”. When you double-tap on the home button and start another application, the previous application is “frozen” and put into a state where it’s not running but can be restarted quickly. A part of the freezing process also reduces the amount of memory being used: allowing more applications to fit in freezer.

The next time you tap on the app’s icon, it is “thawed out” and put back on your iPhone’s screen while the previous app is frozen. This process is repeated each time you launch an app.

This sleight of hand makes it feel like you’re running many more applications than you actually are. It also explains how your iPhone can continue to have great battery life while you interact with many different apps. Most of your apps will be frozen and not using power: only the app on your screen is active. And even with audio, phone or GPS apps that are running in the background, you won’t be using more than one of those at a time (go ahead and try to listen to Pandora and the iPod apps at the same time!)

Hopefully this short explanation helps you understand that the developer of your favorite app isn’t being lazy about doing refreshing in the background! If you feel strongly about this situation, the best thing you can do is give Apple some feedback.

Updated July 1st, 2010: Matt Neuburg has written an in-depth explanation of fast app switching at TidBITS.

APR 23 SO THIS GUY @MACGUITAR GETS IN THE HOT TUB AND SAYS HE WANTS TO SHOW ME HIS THINGS WHAT A WEIRDO MADE @GRUBER JEALOUS TO

APR 24 @jsnell BE CAREFUL OR I WILL MAKE YOU GET IN THE HOT TUB WHAT KIND OF WHINE DO YOU LIKE

MAY 8 WELL LOOK WHOS SHOWN UP AND HE BROUGHT SOME READING MATERIAL COULD IT GET ANY HOTTER IN THIS TUB I HOPE SO

MAY 9 NOW THAT @SIRACUSA HAS FINALLY SHUTUP ABOUT HIS DEEP FEELINGS FOR LARRY WALL WERE GOING TO LEARN ABOUT THE BLINK TAG FROM JEFFRAY PARTY ON

MAY 13 OK WHO LET THE CHICKS IN I TELL YOU WHAT IF SHE STARTS UP WITH THE POETRY SHELL BE LOOKING FOR A WORD THAT RHYMES WITH PALM

MAY 16 WHO THE HELL LET THE KID INTO THE HOT TUB BOY BE CAREFUL OF THE GUY BEHIND YOU HELL WANT TO SHOW YOU HIS THINGS YOU CAN LEAVE YOUR HAT ON TO

MAY 19 I THOUGHT CATS DIDNT LIKE WATER THAT SNEEKY BASTARD @SOCKINGTON IS PROBABLY GOING AFTER MY WHINE

May 21st Looks like Twitter’s avatar uploading is broken. Again.

MAY 21 OR MAYBE IT WAS JUST THAT @ATEBITS AND ME BEING IN THE SAME TUB WAS TO HOTT TO HANDLE

MAY 21 IN MORE IMPORTANT NEWS TWITTER FIXED THERE SERVER SO THE CACTUS FITS IN THE HOTT TUB AND @GRUBER THOUGHT SITTING IN MY LAP WAS PRICKLY

MAY 29 SO ITS BIKINIS ON MONDAY AND WOLFS SHIRTS ON TUESDAYS WHAT ARE WE GOING TO WEAR THE REST OF THE WWDC WHEN WERE NOT IN THE HOTT TUB

MAY 29 AN IMPORTANT AVATER UPDATE IS NOT WORKING AND NO IM NOT WEARING A BIKINI IN IT BUT ITS BETTER

MAY 31 HEY HEY IT LOOKS LIKE THAT FOXY @TJW DUDE LOST HIS HAT ON THE WAY TO THE HOTT TUB AND WHAT THE HELL DOES INMO MEAN http://twitpic.com/59r88

JUN 3 WHO LET THE DOGS OUT THIS HOTT TUBB IS FULL OF PARTY ANIMALS NOW MOOF MOOF MOOF MOOF http://bit.ly/QNz2G AND DONT SPILL MY WHINE

JUN 4 I LOVE TO CUDDLE WITH TEDDY BEARS ESPECIALLY IN THE HOTT TUBB WONDER WHO LET HIM OFF THE FARM IN THAT KEEWEE COUNTRY

JUN 4 OH CRAP ANOTHER BEAR SHOWED UP BUT THIS ONES CANADAIAN AND HES GOT HIS EYES ON MY DRINK HES ALMOST A FRENCHIE TO

JUN 5 WHOA SOMEONE AND THERE ROCK HARD ASS JUST SHOWED UP IN THE HOTT TUBB NEVER SEEN SUCH FANCY SWIM TRUNKS EITHER WHAT AN PARTY ANIMAL

JUN 5 THE HOTT TUBB IS GETTING SO FULL WERE ONLY ALLOWING SUBATOMIC PARTICLES FROM THE HARDON COLLIDER MAYBE HIS EXISTENCE PROOFS THE THEORY

JUN 5 @Curvyboom YOU CHICKS SPEND ALL YOUR TIME ON FACEBOOK PLANNING LUNCH AND WAITING IN LINE FOR THE TOILET NO TIME TO PARTY WITH US ANIMALS

JUN 6 WITH ALL THE CHICKS SHOWING UP FOR WWDC I KNEW ONE OF THEM WOULD TRY TO SNEAK INTO THE HOTT TUBB GOOTEN MORGEN MINE FRAULINE ICH HABEN CHOCK

JUN 6 IT LOOKS LIKE SOMEONE WITH A TELETYPE SHOWED UP TO THE HOTT TUBB ID KICK HIM OUT BUT HIS PALMS LOOK DELICIOUSLY FLESHY

JUN 6 @dsandler ITS EASY TO EXPLAIN JUST SAY THAT ITS PINK AND WARM

JUN 7 ANOTHER DAY ANOTHER CHICK IN THE HOTT TUBB SHES ALMOST AS PINK AS I AM AND I THINK SHES LAUGHING AT US NOT WITH US WONDER IF SHES MARRIED

JUN 7 @AmyJane ILL MAKE SURE TO WHISPER POPS IN HIS EAR WHEN WE HAVE OUR ANUAL SNUGGLE

JUN 8 YOU LOSERS WHO DIDNT COME OVER TO THE YERBO BUENO HOTT TUBB MISSED OUR SURPRIZE GUEST DURING THE KEYNOTE @GRUBER WAS SO EXCITED HE PEED

JUN 9 ITS GOT SO CROWDED IN THE HOTT TUBB LAST NIGHT I HAD SOME GOLDEN GATES INSTALLED SO YOU CAN ALL LEAVE NOW

JUN 10 SOMEONE TURNED UP THE HEAT ON THE HOTT TUBB LAST NIGHT AND IM STILL FEELING A BIT WOOZY ALSO SEEING GRUBER SWEAT IS NASTY

JUN 10 OOOOOOHHH FUZZY BALLS ARE TICKLING MY NOSE IN THE HOTT TUBB AFTER FREE BEER AT THE MAC WORLD

JUN 11 YEAH ITS TRUE I MAY BE GETTING OUT OF THE HOTT TUBB TO PERFORM AT A BASH WORKING OUT DETAILS WITH THE LAWYERS

JUN 11 FRICKEN LAWYERS WONT MEAT MY DEMANDS FOR THE YERBO BUENO SHOW MAY HAVE TO GET A FAMILY MEMBER TO DO IT STAY TUNED FOR OFFICIAL CHOCK ROCK

JUN 11 BTW DONT FOR GET TO USE CHOCKROCK WHEN LOCALIZING FOR JAPAN

JUN 11 IF YOUR LOOKING FOR THE HOTT TUBB ITS CONVENIENTLY LOCATED NEAR THE FOUNTAIN AND KEGS LOOK FOR GRUBER IN HOTT PANTS

JUN 11 YES I AM LIVE TWEETING THE BASH TURN OFF YOUR FRICKEN PHONE SO I GET SIGNAL LOOSER

JUN 11 HOTT TUBB http://yfrog.com/5hgdgtj

JUN 11 CAKE IS BEING SERVED IN THE HOTT TUBB BEER TO

June 12th For me, there will never be a beer bash as special as the one this evening.

JUN 24 AND YOU THOUGHT I WAS JOKING ABOUT MY BUDDY STEVE BEING IN THE HOTT TUBB http://bit.ly/Y8MCf A MAGIC MOMENT

For those of you asking for PDF or Ebook editions, you can order them now directly from O’Reilly. The printed version will be available in a couple of weeks. The “Look Inside” feature at Amazon.com will give you an idea of what the book covers. I’ve also written an overview of each chapter. (And for those of you who are dying to know, the CHOCKLOCK first appears on page ix.)

If you think you know everything about iPhone development, this book will probably prove you wrong. I learned a lot while writing it, and it’s my sincere hope that you’ll benefit from reading it.

First, let me congratulate you and everyone at Apple on the release of the iPad. From my dealings with your company, I know it wasn’t easy. Thanks to everyone for busting their asses: a lot of very complex puzzle pieces came together during those last 60 days!

I recently had an encounter with Bill Atkinson. I told him that “I haven’t had this much fun with a computer since 1984.” He laughed, said “Thanks!”, and went back to working on his iPad app. We, and many other developers like us, are completely smitten with this new device.

After owning an iPad for a little over three weeks, it feels like we’re dealing with something much bigger than that Mac we all got excited about over 25 years ago. I’ve been struggling to define exactly what that is: beyond the technical specifications like the beautiful screen with its large multi-touch surface. Those specifications define what the device can do, but not what it means in our lives. I want to understand the magic.

Last week, much of that meaning came into clearer focus at a birthday party for my brother, niece and nephew (April is birthday month in our family!) My wife had loaded our iPad with photos from a recent trip to see the desert wildflowers in Anza Borrego and my 50th birthday party from the week prior.

Predictably, people’s initial reaction was “Wow, that’s the new iPad!” But that quickly faded as I opened the Photos app and passed the device around. My family was more interested in sharing the photos than talking about the new technology.

I was particularly interested in how my mother, the quintessential technophobe, would react to the device. She picked up on things quickly and was flipping through photos in no time. It astonished me how the interface disappeared for her: at one point she subconsciously licked her finger before “flipping” to the next photo.

As interesting as it was to see someone non-technical use the device, the real eye opener was how several people could interact with the iPad at once. Much of my mother’s fear of computers was overcome because she was looking at the pictures alongside my sister-in-law who helped her out when she got stuck. Learning was organic.

My niece also discovered some of the games I had on the device. One, Abca, was a hit because many people could play it at once. I’ve always played the game by myself and was surprised at how much fun it was to have other people guessing words simultaneously. A group of people transformed the software into something no developer had ever expected.

All of this led to the revelation that we’ve begun a new age of “communal computing.” The desktop revolution centered around empowering individuals: this new revolution will extend that empowerment to groups of people.

The iPad was naturally passed around amongst the partygoers. Many people interacted with it during the evening, and I lost track of who had it at any given time. And therein lies a fundamental problem.

My iPad has a lot of personal information on it: email, business documents, and financial data. When you pass it around, you’re giving everyone who touches it the opportunity to mess with your private life, whether intentionally or not. That makes me uneasy.

It’s hard to fault Apple for this shortcoming. The secrecy of the project undoubtedly limited the amount of group interaction your designers and engineers would experience with their new creation. The social aspects of this device is probably just as much as revelation to them as it is to me.

I can envision several ways to solve this problem: either with a traditional login screen or with something new like folders that require a passcode to open. I have no doubt that your designers can find something elegant that gives me peace of mind as I share my iPad with friends and family.

Thanks for your time and consideration,

Craig Hockenberry

Updated April 30th, 2010: I filed Radar #7922808 for this issue and it was marked as a duplicate of Radar #7584426.

127.0.0.1	gizmodo.com
127.0.0.1	www.gizmodo.com
127.0.0.1	m.gizmodo.com
127.0.0.1	gawker.com
127.0.0.1	www.gawker.com
127.0.0.1	m.gawker.com

The person at fault is the shithead who stole the phone, not some overworked engineer drinking beer.

Please vote with your attention and do the same. Thanks!

(Thanks to @sebastianlewis for the idea.)

Update: I can’t believe there are some people defending Gizmodo’s actions. Let’s put the shoe on your foot:

1. You’re drinking beer with some friends.
2. You leave your wallet behind at the bar.
3. Some stranger finds your wallet and opens it up. Inside is a naked picture of your partner.
4. That stranger finds a website that wants to post the picture and they sell your wallet intact for $1.
5. Your partner finds their naked body on the Internet. Shit hits the fan. HARD.
6. The site that posted the pictures looks at the ID in the wallet and calls up with an offer to return the wallet. “Don’t worry, all the money’s still there!”
7. Then that website posts another article saying how dumb you were for leaving your wallet behind. And instantly millions of people associate your name with a stupid mistake.

How do you feel now?

Update: If you’re the kind of person who forgets that you edited your hosts file, use Marco Arment’s IP address of 66.135.33.106 instead of 127.0.0.1.

Update: For those of you who don’t feel comfortable with the Terminal, here’s a Cocoa application that runs an AppleScript to block Gizmodo. Thanks @digdog!

Native performance

This first benchmark compares the native performance of the iPad against the iPhone 3GS. The version of the iPhone OS is the one originally released with both devices (3.2 and 3.0, respectively.) The application used to test the devices was a release (optimized) build for ARM v7.

On average, the iPad is about twice as fast as the iPhone 3GS when executing native (Cocoa Touch) applications. Great news for developers, because it gives us much more flexibility when creating our apps.

JavaScript performance

Oddly, the same 2x improvement is not seen for the same benchmarks when executing JavaScript code in web pages. Again, the iPad with 3.2 is compared against the iPhone 3GS with 3.0. Things have definitely improved, but there was a wide variation in results when performing the tests. I suspect that just-in-time compilation or other similar types of caching are affecting the results.

The raw numbers really don’t matter anyway: the browser experience on the iPad is exceptional (and will only get better.)

Native performance: Original iPhone vs. iPad

The most remarkable change is when you compare the original iPhone to the iPad. Using the numbers from my original tests and the results above reveals an improvement of several orders of magnitude in just over 2½ years. I believe the technical term for this is “Holy crap!”

Note: I don’t remember if the original tests were optimized builds, or if it was even possible to get gcc to do them with a jailbreak toolchain. Even if they weren’t optimized like the current tests, the performance increases are still stunning.

All-in-all, a remarkable achievement by Apple’s engineers, especially when you consider that the battery life of these devices has gone up, rather than down.

iPad hardware

When using sysctl() to query the amount of memory available to the iPhone OS, the following values are reported:

Again, it’s likely that the device is using 256 MB memory chips with a portion of the total being used for other purposes, such as video memory. Also, developers have noted that all of the 200 MB of user memory is not available for use by apps. The OS and background apps make use of a large portion of that memory.

And last, and unfortunately least, we have the CPU speed reported by sysctl() using HW_CPU_FREQ. It’s zero: the A4 chip is truly magical. I guess that means we have to trust the spec sheet :-)

So hats off to the engineers in Cupertino: the iPad is an inspiring achievement no matter how you benchmark it!

P.S. Check out Twitterrific for iPad to see how we’re putting this processing power to use with our first app for this new platform.

P.S.S. If you’d like to perform these tests on your own, I invite you to download PantsTest.zip.

An important observation that I’ve made with the iPhone is that it’s perfect for “relaxed” computing. I use it while lying in bed, watching TV, waiting for my wife to try on a new outfit, driving through the middle of the desert, and a myriad of other situations where I’m not working.

There’s an inherent benefit to only doing one thing at a time: the load of worrying about other tasks is lifted. Knowing that there isn’t anything else competing for your attention is quite liberating.

Of course, the iPad is an extension of this.

What I find most interesting is the inclusion of the iWork applications. I suspect that we’ll all benefit from working in Pages, Numbers and Keynote without the distractions of the web, Twitter or chat. And in the long run, we’ll prefer it.

The problem started when Pickin’ Time was approved on October 9th. We’ve all been busy working on other projects, so we delayed the launch until October 27th by setting the availability date in iTunes Connect. That gave us time to get the website and other promotional materials finished.

Unknowingly, it also gave us plenty of time to shoot ourselves in the foot. iTunes uses the date of approval as the “release date”, not the day you set for availability.

The result is that there’s no sign of Pickin’ Time in any of the “new” application lists: the casual browsers aren’t finding the app. There’s none of the momentum that’s so important in the App Store.

It’s frustrating that success, after months of hard work, can hinge on something unknown and completely out of our control. The customers who have found the product, are leaving great reviews [iTunes link]. It’s not a question of the game’s quality, it’s a problem of being lost in quantity.

Hopefully, this post will help another developer avoid this unenviable situation. We’d also appreciate any help in getting the word out about Pickin’ Time. Thanks!

iPhone 3G?

It’s entirely possible that Apple will keep the same name as the previous version. There’s precedence in the Mac product line: we’ve had MacBook Pros for several years now with various ways of distinguishing different product iterations (”Late 2008″, “Unibody”, etc.)

Given Apple’s reluctance to publish any of the device’s hardware capabilities, this would seem to make sense.

Except for one small problem. It’s likely that the new iPhone will have a faster processor and more memory. Some applications will be written to take specific advantage of these improvements. And that, of course, means that you need a way to let iTunes customers know if those applications are compatible with their device.

I don’t see Apple putting “iPhone 3G (2008)” and “iPhone 3G (2009)” anywhere in the iTunes UI. It’s just too confusing.

iPhone 4G?

What about having artificial product designations like they did with PowerPC desktop Macs: “G3″, “G4″ and “G5.”

The problem here is that 3G refers to a network service, not a product generation. If this naming convention is used, customers are bound to wonder if a “4G” product works on their 3G network.

iPhone 3G Plus?

So maybe they do something like we’ve seen with the iPod product line. Using terms like “Classic”, “mini”, “nano” and “shuffle” to differentiate the products.

The problem here, of course, is that there’s only one product on sale. Unless Apple plans to keep the current product on sale (at a reduced price,) this just doesn’t make sense.

I’m not going to make any predictions on the device’s name, but I will be paying close attention. The ultimate choice is likely to offer some subtle clues regarding Apple’s plans to evolve this product in future revisions.

Before I get into the actual prediction, let me say that I’ve come to this conclusion by looking at Apple as a business, not as a supplier of shiny gadgets for our technolust. As much as we love the things they make, their goal as a corporation is to make the stockholder’s happy. They do that by selling lots of products. We’re just a means to that end.

A lot of the speculation regarding the netbook says that it provides functionality in the price gap between a $200 iPhone and a $1000 MacBook. While that’s true, it misses the point.

Apple would rather sell you another device in addition to the ones they already sell. They’re not interested in cutting into (presumably healthy) MacBook sales with a netbook. Likewise, selling a bigger touch device could cut into iPhone sales: keep your crappy cell phone and buy the netbook to throw in your purse or backpack.

One of the things that saved Apple was a simplified product line based around professional and consumer uses. Does it really make sense to have more than one consumer-level device for laptop computing? The MacBook already kicks ass in that department: having another device in that category just muddies the water.

But what if there was a device that could work in conjunction with your other Apple products? Something that extended their capabilities. Something that made each product better for a few hundred dollars.

Apple and their shareholders would love this: you’d buy the iPhone and the “netbook”. And eventually the MacBook. And maybe an Apple TV. And probably an iPod, too.

So what are some of the problems with the current hardware lineup?

• iPhone / iPod touch – Small screen, small keyboard.
• Mac – No touch screen, running Front Row prevents using your Mac for other things.
• Apple TV – crappy remote, no keyboard.
• iPod – Very small screen with no touch screen or keyboard.

So what kind of product could fill in these gaps? I call it “Front Row To Go.” Think of it as a second screen for the current hardware. Something that could:

• Display photos on a larger screen than on the iPhones and iPods. It would also be effective as an adjunct to iPhoto on the desktop: Microsoft’s Surface prototype shows how effective it is to display pictures on a horizontal surface that can be manipulated by multiple viewers.
• Provide a touch screen keyboard for the iPhone and Apple TV: a better input mechanism than hunting and pecking on chiclets. (Maybe this is the reason Bluetooth keyboards aren’t available for the iPhone.)
• Show movies on a larger screen: anyone who’s taken a transoceanic flight knows that looking at the iPhone/iPod screen for more than a couple hours can be quite tiresome. An added benefit is that the player’s battery wouldn’t be consumed by the display’s power needs.
• Provide touch input to desktop applications. Multi-touch is never going to happen on a vertically oriented display, so make a separate device that works horizontally. An obvious benefit to developers is that they don’t have to rewrite code: if it makes sense, multi-touch can be added to enhance current applications.

As with all other Apple products, Front Row To Go could obviously work as a standalone device. Sync your content onto the device and take it with you: no more dragging a laptop to a family reunion just because Aunt Bessie can’t see the tiny photos on the iPhone. Get your bookmarks and feeds from the Mac and surf the web using Front Row To Go’s version of Safari while you’re listening to music or watching TV.

As far as how these features would be implemented, that’s anyone’s guess. There might be an API for developers, or maybe it’s a closed system. The device might be able to play iPhone games or run multiple iPhone applications at once (much like the current Dashboard works in Mac OS X.) With a common base of OS X running throughout the product line, pretty much anything is possible.

And that gets to the real point of this essay: think about what Apple has learned from the halo effect surrounding the iPod (and now the iPhone.) If you have any doubt that this effect is alive and well, drop into an Apple Store on any weekend and take a look around: plenty of customers who are happy with one product and looking at others.

In my opinion, these consumers are the ones that Apple will target with a “netbook,” not the ones that are jonesing for a sexy little machine that fills a perceived gap in the product range. I hope I’m right, because I’d love to be one of those customers lining up to buy Front Row To Go.