5 Cool Technical Morsels in Apple’s OS X Mavericks Document

| John Martellaro's Blog

Back in June, Apple released a public document that outlines the interesting technical features of OS X, updated for OS X 10.9 Mavericks. It's what Apple calls a Core Technologies Overview, and it explains in solid but readable technical language what OS X and new core features of Mavericks are all about.

The 35 page document is in PDF format and includes a detailed table of contents. I was pleased to see that the document opens with language that Apple's technical users have come to appreciate in the past.

With millions of users -- consumers, scientists, animators, developers, and system administrators -- OS X is the most widely used UNIX® desktop operating system. In addition, OS X is the only UNIX environment that natively runs Microsoft Office, Adobe Photoshop, and thousands of other consumer applications -- all side by side with traditional command-line UNIX applications."

What's notable there is that Apple appears ready, once again, to celebrate the UNIX basis, heritage and features of OS X that those technical professionals named above have come to love. The tenor of the document reinforces the WWDC demo of Craig Federighi: a celebration of what makes OS X so much better, a UNIX technical elegance combined with terrific usability. Combined with the WWDC announcement of an awesome new Mac Pro, the atmosphere created by this software and hardware pair will be most welcome to many technical customers.

Even so, you don't need to be a UNIX guru to appreciate the document. In typical Apple style, the writing is clear and insightful, not obfuscatory or arrogant. You can learn a lot about your favorite operating system just by curling up with this short, 35 page document and come away feeling a bit more of an OS X expert. Plus, it could come in very handy someday when you're deep into troubleshooting.

Here are just a few of the highlights to whet your appetite.

1. Compressed Memory. "When your system’s memory begins to fill up, Compressed Memory automatically compresses the least recently used items in memory, compacting them to about half their original size. When these items are needed again, they can be instantly uncompressed."

2. App Nap. "App Nap puts applications that you’re not using into a special low-power state that regulates their CPU usage as well as network and disk I/O." This is one of the power saving features of Mavericks, and the explanation is short and easy to digest. It also mentions an item that has been of concern to some—developers can invoke a special API that makes an app ineligible for App Nap. That's so you can put a serious number crunching app in the background, and it will continue to exercise the CPU so that results are ready ASAP.

3. Launchd Recapp. Apple's Launch daemon, developed early in the development of OS X, is one of the things that sets OS X apart from other flavors of UNIX. While not a new Mavericks feature, the explanation here is excellent and somehting every OS X user should understand. Launchd promotes simplicity, interoperability with other OS X features and boot reliability. While it can temporarily throw Linux administrators into a tizzy, because it replaces init, cron, xinetd and /etc/rc, time has proven it to be a superior technology.

4. Sandboxing. For those who aren't developers, the section on Sandboxing, Access Controls, Code Signing and Entitlements clears up some of the mysteries of Mountain Lion and Mavericks security. For those who may have been wondering just exactly what's going on with Gatekeeper (System Preferences -> Security & Privacy -> General -> Allow applications downloaded from:) this section is basically a nifty WWDC session in a box. It's a sumptuous, clearly written explanation of the security Apple has added to OS X.

5. Network Access. Notable here is a section that provides an overview of IPv6 support, the next generation Internet Protocol, in Mavericks. Apple has included the "Happy Eyeballs" algorithm (RFC 6555) for "intelligently selecting between IPv6 and IPv4 addresses when both are available."

This document, in general, summarizes the core technologies of OS X better than any blog article because it's written by Apple. Yet, it is pleasantly crisp, well organized and not too long.  I noted that also included is how to recover access to applications that depend on Java and X11. While it adds, in a few places, some of the new technologies of Mavericks such as Compressed Memory, Timer Coalescing and App Nap, it's not an overview document for all the new Mavericks user technologies announced at WWDC. For that, go to Apple's Mavericks overview page.

Even so, this concise tutorial will provide a handsome summary of all that makes OS X tick. It's also a great way to learn (or relearn) some of the language surrounding OS X as the action heats up prior to the release of Mavericks this fall..

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John Dingler, artist

What’s not nifty is the new X; It looks desiccated, weak, and recessive whereas the previous X looked robust, ready to combat.

Lee Dronick

John, speaking of surfing, the Mavericks X is kind of like San Diego’s much maligned Cardiff Kook. http://thecardiffkook.org/

Mike Weasner

Thanks for the tip on the doc.  Reading it now.  Came across this item on page 7:

“• Is multicore aware. Unlike traditional virtual memory, Compressed Memory can run in parallel on multiple CPU cores, achieving lightning-fast performance for both reclaiming unused memory and accessing seldom-used objects in memory.”

The phrase “lightning-fast” seems more marketing than technical.  Just how is “lightning-fast” defined or measured?  As fast as lightning?  186000 miles per second?  Or just the speed of the lightning bolt?  Or perhaps just the speed of sound of the thunder from the lightning?

I wonder how many more such marketing terms are in this technical document?

John Martellaro

Mr. Weasner:  That document also says, “Compressed Memory is incredibly fast, compressing or decompressing a page of memory in just a few millionths of a second.”

Mike Weasner

Thanks John.  Quoting from the article at http://van.physics.illinois.edu/qa/listing.php?id=533,

“The “leader”, the first stroke of a lightning discharge, actually proceeds in steps—lengthening by about 30 meters at a time, taking about a microsecond (one millionth of a second) to do each step.”

I guess maybe it really IS lightning-fast then.

John Dingler, artist

Hi Lee,
Just checked out the surfer statue. The execution is as weak as the new X. Both pieces deserve malignment and both artists and their bosses who gave the OK deserve opprobrium. But a huge problem with public art of low quality kind is because the local gov. is not willing to pay for good work and the advisory committee is mostly staffed by experts at business not art.

I just hope that the weak and uninspired X—it’s actually quite conservative like Microsoft or any other self-satisfied company—does not portend the same for Apple.

John Dingler, artist

Yeah, I want a muscular X. Oh, I think we had one.


There’s no pleasing some people.

Mike, for ordinary users, “lightning fast” means “very fast” and is perfectly easy to understand. For developers, you either measure it, or you don’t. Easy as that.

Chris Wortman

Having used all of the developer previews I can say this is almost as fast or as fast as 10.6 in it’s current state. They stated they want to get it almost Tiger fast by release. They don’t want anything to come between you and your applications. They want OS X to be invisible to you, and I for One can vouge for it, it is truly very fast.

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