Windows 7 dual versions of same file simultaneously present

Discussion in 'Windows 64bit' started by miktro, Aug 24, 2010.

  1. miktro

    miktro Guest

    I am running Windows 7 Ultimate 64bit.

    I have a situation in which two versions of a file are simultaneously
    present and available to programs.

    Thre is a text file in a program directory from which error message are
    read.

    When I run the program I get an error message "Error 1234".
    When I edit the message file in a text editor this line does not exist.
    There is a new line present "New Error mesage 1234" - as there is suppose
    to be as I have just copied across the latest updated files.

    However if I edit the file using a cygwin command (e.g. 'ed' then the new
    lines are not present but the oldones are!

    Thsi duality seems to hold true for many commands.
    Regular Windows programs see the new file contents,
    cygwin and other 'non-regular' windows programs see the old contents.

    It also holds true after a soft restart, hard reboot and after turning
    off write caching on all discs.

    This also goes even deeper.
    If I delete the file in Windows Explorer then all windows program compain
    tha t the file no longer exists
    but all cygwin programs carry on happily procdessing the old version.

    If I delete this old version using the cygwin comand 'rm' then cygwinalso
    compains the file does not exist.
    Adn if I now copy across a new version then all sets of programs proces
    the same, new version.

    How is this dual presence of a file possible?
     
    miktro, Aug 24, 2010
    #1
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  2. miktro

    Steve Foster Guest

    miktro wrote:

    > I am running Windows 7 Ultimate 64bit.
    >
    > I have a situation in which two versions of a file are simultaneously
    > present and available to programs.
    >
    > Thre is a text file in a program directory from which error message
    > are read.
    >
    > When I run the program I get an error message "Error 1234".
    > When I edit the message file in a text editor this line does not
    > exist. There is a new line present "New Error mesage 1234" - as
    > there is suppose to be as I have just copied across the latest
    > updated files.
    >
    > However if I edit the file using a cygwin command (e.g. 'ed' then the
    > new lines are not present but the oldones are!
    >
    > Thsi duality seems to hold true for many commands.
    > Regular Windows programs see the new file contents,
    > cygwin and other 'non-regular' windows programs see the old contents.
    >
    > It also holds true after a soft restart, hard reboot and after
    > turning off write caching on all discs.
    >
    > This also goes even deeper.
    > If I delete the file in Windows Explorer then all windows program
    > compain tha t the file no longer exists
    > but all cygwin programs carry on happily procdessing the old version.
    >
    > If I delete this old version using the cygwin comand 'rm' then
    > cygwinalso compains the file does not exist.
    > Adn if I now copy across a new version then all sets of programs
    > proces the same, new version.
    >
    > How is this dual presence of a file possible?


    Because Windows protects certain locations from users. The most notable
    example being Program Files.

    It's called File Virtualization.

    The net effect is that attempts by accounts with inadequate privileges
    results in files being created/edited in the users own profile space
    (rather than wherever the user/application thinks the file is), and the
    applications that made the attempts think they were successful. The
    original file is left intact.

    --
    Steve Foster
    For SSL Certificates, Domains, etc, visit.:
    https://netshop.virtual-isp.net
     
    Steve Foster, Aug 24, 2010
    #2
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  3. miktro

    Guest

    "Steve Foster" <> wrote in
    news:-september.org:

    > miktro wrote:
    >
    >>
    >> This also goes even deeper.
    >> If I delete the file in Windows Explorer then all windows program
    >> compain tha t the file no longer exists
    >> but all cygwin programs carry on happily procdessing the old version.
    >>
    >> If I delete this old version using the cygwin comand 'rm' then
    >> cygwinalso compains the file does not exist.
    >> Adn if I now copy across a new version then all sets of programs
    >> proces the same, new version.
    >>
    >> How is this dual presence of a file possible?

    >
    > Because Windows protects certain locations from users. The most notable
    > example being Program Files.
    >
    > It's called File Virtualization.
    >
    > The net effect is that attempts by accounts with inadequate privileges
    > results in files being created/edited in the users own profile space
    > (rather than wherever the user/application thinks the file is), and the
    > applications that made the attempts think they were successful. The
    > original file is left intact.
    >


    Thanks Steve - that sounds like one of the scenarios I suspected.

    My problem now is - how do I tell when this has happened - so I can check
    whether I am using the file I should be using.
    I will need a search condition or test program to flag files where
    virtualisation has occurred.

    Any suggestions would be appreciated.
     
    , Aug 25, 2010
    #3
  4. miktro

    Steve Foster Guest

    wrote:

    > "Steve Foster" <> wrote in
    > news:-september.org:
    >
    > > miktro wrote:
    > >
    > >>
    > >> This also goes even deeper.
    > >> If I delete the file in Windows Explorer then all windows program
    > >> compain tha t the file no longer exists
    > >> but all cygwin programs carry on happily procdessing the old

    > version. >>
    > >> If I delete this old version using the cygwin comand 'rm' then
    > >> cygwinalso compains the file does not exist.
    > >> Adn if I now copy across a new version then all sets of programs
    > >> proces the same, new version.
    > >>
    > >> How is this dual presence of a file possible?

    > >
    > > Because Windows protects certain locations from users. The most
    > > notable example being Program Files.
    > >
    > > It's called File Virtualization.
    > >
    > > The net effect is that attempts by accounts with inadequate
    > > privileges results in files being created/edited in the users own
    > > profile space (rather than wherever the user/application thinks the
    > > file is), and the applications that made the attempts think they
    > > were successful. The original file is left intact.
    > >

    >
    > Thanks Steve - that sounds like one of the scenarios I suspected.
    >
    > My problem now is - how do I tell when this has happened - so I can
    > check whether I am using the file I should be using.
    > I will need a search condition or test program to flag files where
    > virtualisation has occurred.
    >
    > Any suggestions would be appreciated.


    http://support.microsoft.com/kb/927387

    is a useful KB article that explains some of this, and has links to
    further information.

    --
    Steve Foster
    For SSL Certificates, Domains, etc, visit.:
    https://netshop.virtual-isp.net
     
    Steve Foster, Aug 25, 2010
    #4
  5. miktro

    Guest

    "Steve Foster" <> wrote in
    news:-september.org:

    >> My problem now is - how do I tell when this has happened - so I can
    >> check whether I am using the file I should be using.
    >> I will need a search condition or test program to flag files where
    >> virtualisation has occurred.
    >>
    >> Any suggestions would be appreciated.

    >
    > http://support.microsoft.com/kb/927387
    >
    > is a useful KB article that explains some of this, and has links to
    > further information.
    >


    Thanks again - a very useful article.
     
    , Aug 25, 2010
    #5
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