OneSync is a free and open source

Open source

The term open source describes practices in production and development that promote access to the end product's source materials. Some consider open source a philosophy, others consider it a pragmatic methodology...

 sync tool developed by CodeDroids team. It maximizes lightweight synchronization experience and provides both offline synchronization through thumb drive and online synchronization through Dropbox

Dropbox (storage provider)

Dropbox is a Web-based file hosting service operated by Dropbox, Inc. that uses cloud storage to enable users to store and share files and folders with others across the Internet using file synchronization. It was founded in 2007 by MIT graduates Drew Houston and Arash Ferdowsi as a Y Combinator...

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Functionality

The idea of Light-weight Sync is implemented in OneSync. It basically means that for each sync process, only modified and created files are copied over and stored in the intermediate storage. So, if a user has a folder of 10GB, after the first round of sync, because of the Light-weight Sync, only the files that he or she modifies will be copied over. Hence, as long as the user only modifies or creates files which have total file size that is less than 2GB, he or she will be able to sync the 10GB folder through the Dropbox

Dropbox (storage provider)

Dropbox is a Web-based file hosting service operated by Dropbox, Inc. that uses cloud storage to enable users to store and share files and folders with others across the Internet using file synchronization. It was founded in 2007 by MIT graduates Drew Houston and Arash Ferdowsi as a Y Combinator...

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The new Sequential Sync of Multiple Sync Jobs feature is available in the first version of OneSync released in April 2010. With this feature, the user can now easily sync multiple folders in just three simple steps for each computer.