Late to the party but let me throw in a few bits of info.

I've been using SFFS for years and it is a very nice application and works very well. Tobias provides great support and the product is being continually improved. I can't see where it does partial backups though and can't see how it can, as is?

RSync type applications are of no use where the source and destination files are on the same PC, even if the destination is on an external hard drive. RSync is a client/server program and its purpose is to minimize the amount of data (traffic) that needs to be sent between two computers in order to synchronize files. The client and server read the files in their entirety, several times in fact and send data back and forth to determine what parts of the files have changed. The client finally sends just the parts that have changed to the server. So the data going down the wire is minimal but the CPU and Disk use at each end is higher than a simple Copy (Backup) process.

Also note that RSync et.all. are useless where the content of files changes dramatically over time. For example lets say you have a 100 files and only two have changed. RSync will perform very well here. But if you Zip up these 100 files and use RSync on the zipped file you will probably find the entire file is sent down the wire. This is simply because most every bit in the source and destination zip files have changed. Encrypted files such as TrueCrypt containers similarly won't work effectively.

Re. Surfulater. I'm slowly working a database synchronization where only the changes are sent between copies of Surfulater.

HTH.

cthorpe, a very good review. It would have been good if your screen cast went on to show the layer being deactivated and activated. A small quibble though.

I tried SVS a month or so back and found the UI very unhelpful and unintuitive and in the end gave up. I should give it another shot. It certainly seems like a great way for people to evaluate software without their PC being modified in any way. I'm sure this is the main reason why so many people have problems with Windows, because they install so much crap and uninstalling doesn't always remove everything. I use VMWare Workstation for this and for testing my own software and it is invaluable.

There is a lot happening with virtualization right now and interesting times lay ahead. I've recently written a lengthy article XEN and the art of Virtualization about XenServer which DC readers might find of interest.

I'm very interesting in knowing more about how the code works and possibly helping in its development. There is a definite need for this sort of capability. ie. The ability to run apps without them touching the users PC in any way. This is something I want to do for my program, Surfulater. Unfortunately I don't have much time to help in testing though.