Learn more about Apple ID. If you use a different Apple ID for iTunes and iCloud, and want to restore from a backup, first enter your Apple ID for iCloud. After your device restarts, you'll be asked to enter the Apple ID that you use with the iTunes Store, App Store, or iBooks Store.
File system repository. The file system repository allows access to files which have been uploaded (e.g. via FTP) into designated folders on the server. A file system repository may be available site wide for everyone or within an individual course (set up by admin) or for an individual administrator.
A RAR file (short for a Roshal Archive Compressed file) is a compressed file, or data container, that holds one or more other files and folders inside of it. Think of a RAR file like a regular folder on your computer, where there are sometimes many other files and folders inside of it for the purpose of organizing them. However, unlike a normal folder, a RAR file needs special software (more on this below) to open and extract out the contents.