The sync app replicates the files stored on a local machine or machines with the collection of files stored in the cloud. For a desktop PC with a terabyte harddrive and just 100 GB in the cloud, this isn't a problem. But for a typical tablet with 16 or 32 GB of storage, it's physically impossible for 100 Gbytes of cloud files to be copied down to the tablet. That's the problem the latest Windows 8.1 version of SkyDrive was designed to solve.
In the new Windows 8.1 version, SkyDrive will only cache a portion of the file—a thumbnail of an image file, for example, or metadata that tells PowerPoint what presentation the file contains. If necessary, and if the user is connected, SkyDrive will download the total file so that the local application can access it. (Users can also select files to store offline, as before.) The bottom line is that SkyDrive now caches about 1 percent of a user's data store, dramatically saving local storage.
Mehta wouldn't say whether the same techniques would be applied to the SkyDrive data available to Windows Phone, but it's a likely bet.
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