We were discussing document libraries including OneDrive and OneDrive for business. OneDrive for Business is different from OneDrive for users. The former is an integral part of Office 365 or Sharepoint Server and provides place in the cloud where users can store, share and sync their work files.  It is managed by the organization with the help of Sharepoint services and is virtually isolated from any or all personal storages of users such as OneDrive personal accounts.  That said, the files are easy to be moved from one to the other if the users have setup access using corresponding accounts.
Sharepoint services is however different from OneDrive for Business. While both are offered through Office365 business plans, OneDrive for Business evolved from Sharepoint workspace and before that Groove whereas Sharepoint online is a Cloud-based version of the Sharepoint Service that dates back to Office XP. Both are powered by Sharepoint. While one is referred to as location, another is referred to as team site. All files in the former default as private while those in the latter inherit the permissions of the folder they are uploaded in. The interface is also different between the two where the former is exclusive to the user and the latter has a theme shared by the organization.

File Synchronization services allow files to be sync’ed between local desktop and the cloud. The Microsoft Sync framework is actually well known in this space. It is a comprehensive synchronization platform that can synchronize any type of data, using any protocol over any network. It uses a powerful metadata model that enables peer to peer synchronization of file data with support for arbitrary topologies. One of the main advantages for the developers is that they can use it to build file synchronization and roaming scenarios without having to worry about directly interacting with the file system.

Some of the features of this system include incremental synchronization of changes between two file system locations specified via local or UNC path, synchronization of file contents, file and folder names, file timestamps, and attributes. It provides support for optional filtering of files based on filenames/extensions, sub-directories or file attributes. It provides optional use of file-hashes to detect changes to file contents if file timestamps are not reliable. It provides reliable detection of conflicting changes to the same file and automatic resolution of conflicts with a no-data-loss policy. It allows for limited user undo operation by optionally allowing file deletes and overwrites to be moved to the recycle bin. It supports Preview mode which provides a preview of the incremental synchronization operation without committing changes to the file system. It lets user start synchronization with equal or partially equal file hierarchies on more than one replica. It supports graceful cancellation of an ongoing synchronization operation such that the remaining changes can be synchronized later without having to re-synchronize changes that were already synchronized.