Communal computing

Dear Steve,

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.

An apology…

Until Gizmodo publicly apologizes to Gray Powell, this is going to be in my /etc/hosts and in all of the DNS servers under my control:

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 instead of

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!

Benchmarking in your lap

It’s been a little over 2½ years since I last looked at the performance of Apple’s mobile devices. A lot has changed with the software and hardware since then, let’s take a look at how the new iPad compares to the devices we’re more familiar with.

Native performance

Test iPad/3.2 iPhone 3GS/3.0 Faster by
100,000 iterations 0.000035 secs. 0.000137 secs. 3.91x
10,000 divisions 0.000010 0.000018 1.8x
10,000 sin(x) calls 0.000012 0.000018 1.5x
10,000 string allocations 0.004321 0.007915 1.83x
10,000 function calls 0.000338 0.000600 1.78x

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

Test iPad/3.2 iPhone 3GS/3.0 Faster by
100,000 iterations 0.011 secs. 0.017 secs. 1.55x
10,000 divisions 0.006 0.012 2.00x
10,000 sin(x) calls 0.009 0.024 1.85x
10,000 string allocations 0.007 0.017 2.43x
10,000 function calls 0.005 0.006 1.20x

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

Test iPad/3.2 iPhone/2.0 Faster by
100,000 iterations 0.000035 secs. 0.015 secs. 428x
10,000 divisions 0.000010 0.004 400x
10,000 sin(x) calls 0.000012 0.105 8,750x
10,000 string allocations 0.004321 0.085 20x
10,000 function calls 0.000338 0.004 12x

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:

Kind Bytes Megabytes
Physical (HW_PHYSMEM) 258,998,272 247 MB
User (HW_USERMEM) 210,284,544 200.5 MB

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