Sounds like a great idea, but not exactly revolutionary.  In the 80&#x27;es I saw at least one implementation of this which migrated between tapes(!), hard drives, and memory.  I always wanted this.<p>CODA [1] implemented parts of this as well.<p>Unfortunately, Dropbox has unencrypted access to all files and is too expensive, otherwise I&#x27;d be all over this.  I&#x27;d rather allocate funds towards an open source implementation (I think something interesting would be done based on idea from CODA and NFSv4).<p>[1] <a href="http:&#x2F;&#x2F;www.coda.cs.cmu.edu&#x2F;" rel="nofollow">http:&#x2F;&#x2F;www.coda.cs.cmu.edu&#x2F;</a>