Inside OS X 10.8 Mountain Lion GM: using iCloud as the smart, automated way to store documents
iCloud's Documents & Data
While iWork's desktop cloud support hasn't yet arrived, other apps Apple bundles with OS X demonstrate iCloud's "Documents in the Cloud" model in Mountain Lion. This support is dependent upon the type of documents and data an app uses.
For example, in Mountain Lion, Safari 6.0 makes transparent use of iCloud to store and display the tabs open on other devices (as noted above), as well as the user's Reading List and other Bookmarks. Reminders and Notes similarly share their data across a user's devices without explicitly saving actual documents, just like Mail, Calendar and Contacts.
Bundled applications that are oriented around saved documents, such as TextEdit and Preview, illuminate how iCloud's "Documents in the Cloud" will function. By default, both apps offer to save new documents to iCloud (as depicted in their Save dialogs, below).
When targeting iCloud as a save location, the disclosure triangle that would normally allow users to browse files and folders in the file system is greyed out. There's also no button to create a new iCloud Folder (you create these like iOS, by dragging file icons together. As on iOS, "Folders" in iCloud are not standard file system subdirectories, but simply organizing features that only exist one level deep.)
In previous builds of Mountain Lion, the disclosure triangle did function, and presented a more complex view of iCloud's files within TextEdit (below), complete with file type options, a button to create a new folder, and a Finder-like sidebar of other locations in the file system. That's all now gone in the latest build.
Rather than trying to make iCloud appear to be an extension of the desktop file system, Mountain Lion treats iCloud as an alternative location outside the file system, and which doesn't work like the file system (no nestled hierarchies of folders, for example). In contrast, OS X has always treated removable devices and remote servers (including MobileMe's iDisk) as if they were an expansion of the file system, rather than a parallel universe of storage. Dropbox cloud storage similarly presents its files as a local folder within the user's home directory. So iCloud's presentation is a new concept.
Stated simply: while iDisk, Dropbox, local servers and removable disks are all presented as in being in a hierarchical structure rooted to the local computer, iCloud and its contents (including documents and organizing folders) exists in an entirely separate world distinct from the local computer's file system.
iCloud without the cloud
In order to explicitly not save files to iCloud, users can simply pick a folder in the local file system (including on a remote server or to a Dropbox folder) instead when saving. The same standard popup menu also allows users to specify saving a file to iOS-style Folders created within iCloud (below, a "Screenshots" Folder is listed as a save target, as well as local disks and Finder sidebar "favorites").
The advantage to saving files to iCloud is that they'll be managed by Apple. You don't have to worry about which desktop you saved a particular file on; as long as your system is connected to iCloud, you'll see the same set of files across all your systems (and mobile devices, in the case of cross platform apps such as iWork titles).
What happens when you work offline with no Internet connection? It appears OS X mirrors all of your iCloud files locally, as even when unplugged from the Internet, you can still see the files you've saved to iCloud. You can also save files to iCloud without a network connection. Of course, they will continue to be cached locally until you again connect to the Internet.
As with the new ultra streamlined, option free iCloud save dialogs (show above), open dialogs showing the files available on iCloud have a simple interface reminiscent of iOS: a distinct, dark linen background with icons that can be selected and grouped into Folders (as depicted below). There are two view options: an icon mode and list mode offering some additional file information.
From on open file dialog, local files you've saved while offline appear with a iCloud "dotted outline" icon. In file icon view, the document's icon is badged "waiting" to indicate that the file hasn't yet synced up with Apple's servers (and therefore won't be accessible from other systems until it does).
iCloud not found in the Finder, but still searchable
iCloud-savvy apps show what documents the user has created and saved to iCloud within these special, simplified save and open file dialogs, but those files don't show up anywhere in the Finder. That is, until you perform a Spotlight search.
If you go looking for an iCloud repository of files in the Finder akin to the previous .Mac/MobileMe iDisk (or Dropbox), you'll come up empty handed. There's nothing pertaining to iCloud in the Finder sidebar, no icons on the desktop, no Dock icon, nor any other clue that there are files you've squirreled away in iCloud. But perform a Spotlight search for an iCloud file and it immediately appears in the results within a Finder window (shown below). Why?
Because iCloud isn't part of the old file system concept that the Finder was intended to put a face on. Jobs wasn't just speaking hypothetically when he asked, back in 2005, "why is the file system the face of the OS!?" While he presided over the development of the original Macintosh Finder back in the early 1980s, he also, with iCloud, helped to conceptually craft the beginning of its demise 30 years later, much the same as he did in both introducing and then later eradicating 3.5" floppies.
The reason iCloud doesn't have a static "spot" in the Finder is because iCloud's "Documents in the Cloud" do not exist as system-wide files. Each application's iCloud files are tied to that application. Graphics and PDFs you work on in Preview and save to iCloud are only visible within Preview. TextEdit files you create and save to iCloud are similarly only visible when you're using TextEdit.
Other applications, including a hypothetical bit of malware designed specifically to erase your local files, can't access TextEdit's iCloud documents because Apple has created a new layer of per-app security that erases the notion of a shared file system that every app can access.
This type of security is similar to the concept of multiuser accounts, where two or more users can securely log into the same Mac, but don't have access to each other's documents saved within their private home directories. Apple has taken the idea of multiuser security (new to Mac OS X a decade ago; the Classic Mac OS didn't offer this in the 1980s and 1990s, even while Unix and Windows NT did) and has applied it to applications.
This "new in Mountain Lion" concept of app-level security isn't new at Apple. It's already been in practice on iOS for the last five years. iOS apps store their own files within their own local sandbox. There's no Finder for iOS, because there's no public file system for users to wade through. Such a design couldn't be imposed upon Macs because the Finder and its wide open file system already exist.
However, iCloud offers a new opportunity for enhancing the security of file access between apps, and for greatly simplifying the user experience of document management without requiring users to deal with the complexities of a file system, including the physical barrier imposed with saving files to a particular device in an era where we now regularly use multiple devices from mobiles to desktops.
On page 3 of 3: Files aren't stuck with a specific app