Windows Vista Forums

Maximum number of characters in file name extension

  1. #1


    pc nerd Guest

    Maximum number of characters in file name extension

    Does Vista (& XP) set a limit on the maximum number of characters in a file
    name extension? I know that XP will open files with 4 characters (for
    example, .html). So, is there a maximum number of characters in a file name
    extension? Does Vista (& XP) allow numeric characters or punctuation marks or
    other typable characters? Does Vista (& XP) allow a combination of alphabetic
    & numeric & alphanumeric characters in a file name extension?

    Thank you.

      My System SpecsSystem Spec

  2. #2


    Andrew McLaren Guest

    Re: Maximum number of characters in file name extension

    "pc nerd" <pcnerd@xxxxxx> wrote ...

    > Does Vista (& XP) set a limit on the maximum number of characters in a
    > file
    > name extension? I know that XP will open files with 4 characters (for
    These limits are defined by the NTFS file system. Windows XP, Server 2003
    and Vista all use version 3.1 of the NTFS file system.

    NTFS naming convensions are described here:

    Naming a File
    http://msdn2.microsoft.com/en-us/library/aa365247.aspx

    The total length of the filename (basename plus extension) is 255 chars.
    There is not specific limit on the extension length (eg you could have say,
    200 char basename and 55 char extension, or even 1 char basename and 254
    char extension).

    All pathnames must generally fit within MAX_PATH, which is 260 chars
    includng the final NUL char.

    Some other handy references:

    How NTFS Works
    http://technet2.microsoft.com/window....mspx?mfr=true

    Making Room for Long Filenames
    http://msdn2.microsoft.com/en-us/library/ms810456.aspx

    Different conventions apply for FAT and FAT32 file systems, obviously. These
    are pretty much in the legacy class, except for removable media like USB
    drives. Vista SP1 will introduce support for the exFAT file system, for
    flash drives and similar scenarios.

    Hope it helps,

    --
    Andrew McLaren
    amclar at optusnet dot com dot au



      My System SpecsSystem Spec

  3. #3


    davidfowler2000 Guest

    Re: Maximum number of characters in file name extension


    Does Windows set a limit on file extension length?

    Not as such. Filename extensions are just the bit after the dot and
    Windows just uses it as a guide as to what program to pass the file to
    to open it. The whole thing counts as the file name. As long as the
    filename (INCLUDING the directory path) doesn't exceed 255 characters
    then you can have whatever you want).


    > Does Vista (& XP) allow numeric characters or punctuation marks or
    > other typable characters?
    The operators like * / \ ? " <> aren't allowed because they are wild
    cards (used by programs / command prompts to perform actions e.g. - *
    means all - *.mp3 is all files ending with .mp3)

    > Does Vista (& XP) allow a combination of alphabetic
    > & numeric & alphanumeric characters in a file name extension?
    >
    What about .mp3? Last time I checked, XP could open my music files



      My System SpecsSystem Spec


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