What's left for Apple's OS X to grab from iOS?

Apple's upcoming Mountain Lion software update for the Mac certainly isn't bashful about borrowing features from iOS, but what the company chose not to add is a story in itself.

As we covered before, the release is largely a collection of new software that came as part of iOS 5, software Apple released for the iPhone, iPad and iPod Touch in October. That includes software like Reminders, iMessage, and Notification Center, all of which now come pre-installed on the Mac and ready to sync up with their iOS counterparts.

But not everything came along for the ride. There are still a handful of features that Apple's left out. Below are four notable omissions.

Note: Apple says Mountain Lion is still a work in progress, and that features may change ahead of its release. There could also be a surprise or two that weren't ready to go today.

Siri
Siri, the voice assistant feature introduced as part of the iPhone 4S, is not a part of the Mountain Lion preview. That's a curious thing given Siri's role on the iPhone 4S. There it's tied into a handful of apps that are now a part of Mountain Lion, including Notes, Reminders, and Messages, as well as software that was there in previous OS X iterations, like Mail, FaceTime, and Apple's Dashboard widgets for checking the weather and stock prices.

But bringing the voice assistant feature to the desktop likely presents a challenge to Apple. Would people feel comfortable talking to their computer, versus something like a phone where they're used to speaking into it to make phone calls? More important, Siri is really a feature that's about skipping people beyond having to fumble to unlock their phone, find an app and start pecking away. On a computer, there are fewer of these hurdles.

But if it were to be added, how much run do you give it of the system? On the iPhone, the Siri software is strongly limited from doing much more than helping you do search queries, create and edit alarms and appointments. Two things it can't do are launch software programs or help you find files--tasks people would be likely to want to use it for on the Mac.

iBooks
Perhaps one of the most glaring omissions in Mountain Lion is iBooks. You can throw this into the pile of things that might come in the final release and is simply not part of this developer preview, but it's peculiar. Why? Apple has a vested interest in expanding the utility of its iBookstore, and purchases people have made on it.

When asked why this wasn't in there during a briefing last week, the company provided no answer--nor any indication that iBooks might arrive at a later date.

Competitor Amazon has run laps around Apple when it comes to e-book availability, bringing versions of its Kindle reading app to multiple platforms--including mobile phones and as native desktop applications on Windows and Mac. Last year the company took it one step further, launching its reader as a Web appthat runs in the browser.

Another reason why I'd expect to see iBooks on the Mac--at least eventually--is that Apple's got an unusual situation on its hands in the sense that people can now create books for the platform on a Mac, but still can't really see how they look. Last month Apple released the iBooks Author software as a way for people to create books and text books, but the software requires the user to own an iPad to give their creations a test run. A proper reading application would solve this problem.

Newsstand
Part of the iBooks/iBookstore ecosystem, Newsstand is the iOS 5-specific feature that lets people read and subscribe to newspapers and magazines that get both delivered and updated in an organized fashion. The obvious reason why it's not a part of Mountain Lion preview would seem that the feature was designed largely to corral news reading apps and self-updating magazines. On a Mac people can get that same news through the browser, and magazines haven't taken hold in app form like they have on Apple's iPad.

Still, the same argument about Apple having a vested interest in bringing a way to view iBooks content on the Mac holds true with this. It's a chicken and egg problem in that there truly needs to be something built for publishers to come. The bigger question is whether Apple would introduce iBooks for the Mac without bringing Newsstand along.

iCloud back-up/restore
One feature introduced in iOS 5 that is not present in Mountain Lion's preview is a built-in back-up and restoration from iCloud. On iOS, this lets you make a nightly snapshot of your gadget for safe storage on Apple's servers. You can then recover that copy back to that device, or another one anywhere you have an Internet connection.

On something like a notebook or desktop, Apple's treated this back-up need with Time Machine, a more advanced tool that takes multiple snapshots of your entire computer's file system and lets you make a full restoration, or just grab a copy of a particular file at a particular time.

The limitation with Time Machine is that you need to be plugged into a hard drive or wireless storage device (like Apple's Time Capsule) to make those off-computer back-ups; you can't just connect to Apple's servers. Apple does, however, offer a built-in Internet Recovery feature that will return your computer to the stock version of Mac OS X.

The simple reason that isn't here is space. iCloud's been designed to store and ferry over individual files and settings, but the available storage there is nowhere close to what desktop users might need for Time Machine-style back-ups. For instance, its low-end plans bring the storage up to 15GB at a price of $20 a year, maxing out at $100 a year for the 55GB plan. By comparison, Apple's entry level notebook, the MacBook Air, ships with 64GB of built-in storage.

Apple's taken some steps here with deeper integration of storing those files in iCloud, but it's a different paradigm from the comprehensive solution found with Time Machine. Will something like that arrive sometime in a future version of OS X? Perhaps, but don't count on it in Mountain Lion.