Those OS X iPods? They're Already Here!  Pixo, ARM, and the Mac OS
Speculation has run rampant over how Apple might bring iPhone technologies to its iPod line. Will the next generation of iPods look like the iPhone and run the same software? It turns out I stumbled upon the answers six months ago. Now I've discovered additional proof. You’ll be surprised to find that much of what we all thought we knew about the iPod was wrong.
[Warning: this article has proven to be confusing to those skimming its surface. It involves some subtlety [which has been struck out so as not to distract from the point of the article]. If you would like to read the core essence of this article at a simpler reading level [written for comic effect], proceed to THIS LINK. If you can handle a more complex presentation, you are welcome to proceed.]
The iPod’s ARMs
Back in January, John Gruber of the Daring Fireball posted an article “At ARM’s Length,” which pointed out that Apple was distinguishing between Mac OS X and the iPhone's OS X. He also suggested that the iPhone's ARM processor was something Apple hadn't dealt with since the 1994 - 1998 Newton Message Pads.
In the article “Inside the iPhone: Mac OS X, ARM, and iPod OS X,” I pointed out that the Apple has been using ARM processors since 2001, wrapped up inside the iPod. In fact, most iPods have two ARMs, which I coyly referenced in the headline of an article about iPod games, “Apple’s New Dual Processor Game Console.”
I thought it was weird that Apple was distinguishing between Mac OS X and OS X on the iPhone; they are really the same thing, just running on different processor architectures.
Stumbling on to Something.
I then suggested that OS X had been the secret iPod OS all along:
“It is actually possible that iPods have used a subset of Mac OS X code for some time already, in secret. Apple has never made any comment on what operating system existing iPods run, ever since the company moved from Pixo, the operating system that ran the very first iPods.”
I drew a parallel between Apple's secret maintenance of Mac OS X for Intel, which wasn’t revealed until WWDC in the summer of 2005, just six months ahead of the release of new Intel Macs in January 2006.
“Now, six months ahead of the iPhone’s release,” I wrote back in January, “Apple may similarly be ready to reveal a parallel secret: that Mac OS X software, ported to the ARM processor architecture, has actually powered iPods for years.”
It turns out the only thing I was really wrong about was the iPod’s “Pixo operating system,” a key part of the story of the iPod and widely assumed to be a well known fact. The problem is that it isn’t.
Pixo: Just The Icing.
Apple never officially made any announcements about the iPod’s operating system architecture, and provides no developer documentation on how it works internally. The idea that the iPod runs an operating system called Pixo was assembled from a variety of sources:
  1. Early iPods credited Pixo software in their About iPod menu.

  2. Pixo, Inc was founded by Paul Mercer and other developers from Apple's Newton project.

  3. In 2004, the San Francisco Chronicle reported “Pixo was on board to help Apple create an operating system that would run the user interface of the iPod.”

  4. The Connectix corporate bio of VP of Engineering Mike Neil called him the “lead architect on the Pixo OS that is used in ... the Apple iPod.”
It seemed well established that Apple had outsourced the iPod’s operating system to Pixo back in 2001 in order to deliver the new device as rapidly as possible. What had happened since was unclear, because nobody seemed to know anything about Pixo or anything else inside the iPod, apart from its headline generating batteries.
Was the iPod Even an Apple Product?
Apple critics liked giving the credit for the iPod’s success to anyone else apart from Apple, resulting in the legend that iPod was carried by Pixo. As one blogger wrote, “The more that is divulged about the history of the iPod, the more we understand that Apple merely aggregated various pieces of technology.”
The Chronicle article about Pixo cited Paul Saffo, director of Menlo Park's Institute for the Future as proclaiming that “the fact that Apple went to Pixo suggests ‘that they tried it inside and failed.’”
If the iPod’s success hinged upon Pixo, why hasn’t the company or its other clients done anything interesting? Pixo ended up getting bought up by Sun, which certainly hasn’t shipped anything like the iPod. Sun acquired Pixo for its mobile Java download server.
Mercer went on to develop the interface for Samsung’s Z5, which went nowhere before becoming a casualty of the Zune after Microsoft abruptly abandoned its PlaysForSure partners. This March, Mercer was hired as part of Palm Inc.’s iPhone defense panic.
Perhaps the iPod’s success did have something to do with Apple after all. It turns out that Pixo isn't really an operating system; it’s a graphics and user input layer for mobile devices, similar to the X Window System for Unix or the Mac's Quartz graphics and window management layer, although obviously Pixo is much simpler.
iPod Digging.
If Pixo isn’t running the whole show inside the iPod, is is possible that Apple actually contributed some work toward the device’s success itself? [Update: reader Gavin Lynch found this diagram of the Pixo architecture hiding in the Internet Archive’s Wayback Machine:]
[Update: This passage was regarded by many readers as being poorly written, and “incomprehensibly obtuse in its intermingling of serious points and irony.” To rescue the message from its presentation, I have struck out everything that alluded to Tim Monroe’s spoof. What remains is intended as a serious article. I apologize to anyone who received the original article as confusing or misleading. It was not intended as such.]
Attaching an iPod in disk mode and navigating to the iPod_Control/Device directory, we find:  
-rwxrwxrwx  1 dan     unknown  2872 Jul 12 13:55 Prefs
-rwxrwxrwx  1 dan     unknown   413 Jul 12 05:55 SysInfo
drwxr-xr-x  5 root    wheel     190 Jul 12 08:33 bin
drwxrwxrwt  6 root    wheel     204 Jan 24  2003 cores
dr-xr-xr-x  2 root    wheel     512 Jul  6 13:38 dev
lrwxrwxr-t  1 root    admin      11 Jul  6 13:38 etc
-r--r--r--  1 root    admin  709440 Jul  6 13:38 mach.sym
-rw-r--r--  1 root    wheel  744576 Jul  1 15:21 mach_krn
Oh dear, it turns out the iPod is running Mac OS X--with a Mach kernel and a Unix userland--and has been for years. Add another +100 million iPods to the list of Mac OS X powered devices on the planet. The Windows Enthusiasts are not going to like this!
After years of spoofs about running Mac OS X on the iPod, from a April Fools Joke in 2005, to the  fake YouTube video regularly unearthed to titillate the readers of Digg, it turns out that truth was that iPods have been running OS X all along. Or at least that makes for a good story.
The OS X iPod.
Of course, the iPod isn't a high powered device; various models only have 32 - 64 MB of RAM. That means the iPod can't handle Quartz graphics, which is why it’s running Pixo’s graphics layer instead. In contrast, the iPhone can run Quartz and the rest of Mac OS X within its 128 MB of system RAM and its 700 MB of consumed Flash.
That helps explain why Steve Jobs keeps calling the iPhone “the best iPod we've ever made.” It isn't just marketing fluff about the iPhone having some music playback features; the iPhone actually is an iPod, built using the same ARM processor architecture as the iPod and the Mach and Unix based OS derived from Mac OS X.
Tim Monroe, a member of Apple's QuickTime engineering team, outed this secret years ago in an issue of MacTech. That article was forwarded to me by Layne Lee, a reader in Korea. It was indeed an April Fools joke.
Monroe [update: in his April Fools joke] pointed out that the original iPods's applications were built using a scripting language called SNOJOB, a version of the SNOBOL language with bindings to the Pixo imaging system. He went on to explain how users can write their own iPod applications.
The OS X iPhone.
Over the last several years, that potential for custom iPod applications went untapped, despite the deployment of over 100,000,000 iPods. Either that, or SNOJOB was too difficult.
That may have played a factor in Apple's decision to leave the iPhone closed for custom development, but more likely, Apple never intended custom development for the iPod or the iPhone. Seeing the success of the iPod as an appliance, Apple moved ahead its plans to deploy the iPhone in the same way.
Since it incorporates a rich interface with WiFi access and mobile voice and data connectivity, the iPhone has found a lot more interest among developers. A number of developers targeting the Enterprise are deploying web-based applications for it, and hackers are trying to find their way inside to install their own apps.
There has even been considerable interest in spoofing the activation process in order to use the iPhone as a full featured wireless web browsing iPod.
The Future of OS X.
Apple isn't just ahead of the game in mobile phones with the iPhone. It has a complete mobile and embedded software platform that is turning heads in a number of industries.
Just as Mac OS X delivered--years ahead of schedule--what Microsoft promised to ship with Vista, Apple’s OS X is actually doing what Microsoft promised but failed to do over a decade of WinCE development.
Looking at the range of specific applications Microsoft has promised for WinCE in automotive and handheld devices gives some inkling of the market Apple can grab with OS X.
Given how much attention the iPhone has already captured, and how badly Windows Mobile and its WinCE foundation have performed in the market, it would appear Apple has a lot of potential for new growth in 2008.
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Sunday, July 15, 2007