Naturally, Microsoft has also updated the built-in Modern-style SkyDrive app in Windows 8.1. Besides some tweaks in tile sizes, for the most part, it works the same as the current SkyDrive app. The most notable addition is that you can now get to your locally stored files. Just click the SkyDrive title at the top left, and choose ‘This PC’ from the drop-down box. It shows the same items that are in the This PC section in the File Explorer on the desktop, such as your personal folders, devices and drives, and network locations. Yes, the new SkyDrive app is your Modern-style File Explorer.
On Windows 8, the Modern-style SkyDrive app is best used for uploading files to and downloading existing files from SkyDrive. For more granular control, especially when you’re working in the desktop environment and if you need offline file access, we recommend installing the desktop SkyDrive app. It creates a SkyDrive folder on your PC, and everything you put in it (and any changes thereafter) will be synced between all your PCs and SkyDrive in the cloud.
For Windows 8.1 however, the desktop SkyDrive app isn’t needed. When you fire up File Explorer on the desktop, you will see a SkyDrive section at the left sidebar, and it’ll be populated with the same folders as your online SkyDrive. At first glance, it looks like the OS has downloaded all your SkyDrive files - but that’s not quite what happens. In a blog post, Microsoft has detailed how it’s able to give you “access to all your SkyDrive files without actually downloading them, using precious local disk space and Internet bandwidth”, through something called "placeholder files". We’ve taken the liberty to quote Microsoft on what this and some of the other key features do below:
Placeholder Files: “Placeholder files look and feel like normal folders and files. You can tap or click a folder and see all the folders and files inside it. You can tap or click a file and it will open, you can edit it and close it. You can move, delete, copy, or rename placeholder files just like you would any folder or file. But we only download the full file when you access it. What we have in its place is a placeholder file containing a thumbnail image along with some basic properties and file content. This means that the placeholder file is significantly smaller in size that the file in SkyDrive, but when you need to use it, we’ll download the full file for you.”
Update (September 27, 2013): Microsoft is renaming placeholder files to smart files.
Smart Thumbnails: “When you flip through photos, we download large thumbnail images instead of the actual files. And we pre-fetch thumbnails to enable fast scrolling. It’s only when you want to edit a photo that we download the full file to the local disk.”
(According to Microsoft, this combination of placeholder files and smart thumbnails allows SkyDrive files to take up less than 5% on the local drive. In other words, if you’ve 20GB worth of files on SkyDrive online, the same files are still available to you on Windows 8.1, but they only take up 1GB of storage locally.)
Offline Access: “With the SkyDrive app, you’ll be able to mark any folders or files you want for offline access. Edits on this device or another device will be synchronized so that you’re always working with the latest file.”
“We always mark files for offline access if you’ve opened or edited them on this device before. We do that because most people tend to open the same files they recently opened, but the files they open often vary across different devices - so we remember those files and make this unique to the device you’re using.”
Opening & Saving Files: “Any Windows Store app can use the Windows file picker to let you open, edit, and save any kind of file. In Windows 8.1, SkyDrive is built into the file picker - so every Windows Store app can save files directly to SkyDrive without any extra work. And the files will quietly get uploaded in the background so you don’t have to wait around.”
“If you were working in a desktop app, you get the same functionality using the Windows common file dialog - opening and saving to SkyDrive is as easy as saving to your PC.”
Searching Files: “SkyDrive files show up in search results just like your local files. For example, if you have a document in your SkyDrive, we extract a few lines of text from the document and provide that to the search indexer on your device so that it can return search results that are more relevant to you. It goes without saying that search works across your entire SkyDrive (including placeholder files).”
With a doubt, the updated SkyDrive (the backend, the apps) is one of the most (if not the most) impressive piece of work Microsoft has done for Windows 8.1. With waist-deep OS integration, it benefits not just Windows 8.1 users, but Windows RT users too, especially in the area of offline file access. The use of placeholder files and smart thumbnails is also a stroke of genius, because let's face it, most mobile devices still come with relatively low-capacity storage. While some may say that all these should be in the original release of Windows 8, at this juncture, we can only say that it’s better late than never.
Windows 8.1 will launch on October 17, 7:00pm Singapore time, and existing Windows 8 users can update for free through the Windows Store. Windows 8.1 will also be available at retail and on new devices starting October 18.
Update (October 1, 2013): Microsoft continues to add new features to SkyDrive before the general availability of Windows 8.1. For example: Bing-powered OCR (optical character recognition) to photos on SkyDrive and smart files OCR search on the desktop in Windows 8.1.