How to
    prevent users overwiting each others changes
    edit symultaneously

One way to prevent users overwiting each other would be to make them edit the files on DiveHQ directly and have driveHQ lock the file while they are open. Now DriveHQ does not do this I guess because that would mean some files could be locked forever (when they are not saved back). It might be whoth the hassle though if you provided a unlock option.

Another way would be for DriveHQ to always save to another version (It might do this I dont know yet). But there is still a problem - you don't know when this has happened so don't notice it. But DriveHQ could notice if when you save back there has been an update sunce you took a copy.

In general DriveHQ could know the version that each user last took and warn them when they are makeing a new version if the version they took was not the latest.

Chad

Hi, you brought up some very good points!

Lock a file on the Internet is definitely a bad way; not only it consumes a lot of server resources; more importantly, HTTP connection is really "connection-less", meaning the file could be locked even if the connection is dropped. When this happens, files could be locked for a long time before they become editable again.

Now if you use WWWBackup, it always saves new files as new versions. ( There is a limit of 10 versions by default. )

When you use FileManager's folder synchronization feature, if two users changed the same file on two different computers at the same time, then assume User1's change gets saved before user2's. When it is synchronizing user2's file, it will prompt the user: whether to overwrite local or remote.

Overall, the chance for two users editing the same (Shared) file is small. If this happens, special caution needs to be taken.