PeteM PeteM

Niner since 2007


  • Windows Vista "Time Warp": ​Understandi​ng Vista's Backup and Restore Technologies

    Strangely TimeWarp seems have an effect of warping time - changes seem to be made to previous and not current versions of the file.  It is mighty confusing.

    • I have an application which stores its data in a Jet MDB.
    • A User of the application goes in and makes changes then quits
    • A user goes into the application again and changes are viewable (All normal so far)
    • The date and timestamp of the MDB file has not changed on disk (The puzzle begins)
    • A binary compare of the file on disk shows that it is unchanged since the version which was installed (The riddle deepens)
    • Delete the MDB (Sanity lost from this point forward)

    The user runs the app again - lo and behold it no longer works crikey it still works even though its data file has been deleted!  If the user goes into the options in the application to choose the data file then they clearly see the file which has been deleted and which is not visible by Exploring to the folder. 

    My conclusion is that my application (at least for this one user - will all other users link to the same 'previous' version which contains current data?) is using a previous version.  Certainly not what I would have envisaged.

    What *exactly* is going on here? How can I control all of this? More's to the point - how can I possibly rely on my operating system not playing with my sanity?

    Only further point to add - This scenario has the MDB located in a sub-folder of Program Files - I am upgrading my app to work under Vista where the data file should be held elsewhere.  I was testing the 'existing XP user upgrading to Vista' scenario expecting that they would get an error when the MDB was opened since it *should* have been read-only as a result of being in Program Files.