NT4 & backup program - Windows NT

This is a discussion on NT4 & backup program - Windows NT ; Greetings, I am using the default backup program that comes with NT 4. I am launching it from the command line with the hc n flag. My tape drive is an HP Dat24i (which is SCSI). I am using HP ...

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  1. NT4 & backup program

    Greetings,
    I am using the default backup program that comes with NT 4. I am launching
    it from the command line with the hcn flag. My tape drive is an HP Dat24i
    (which is SCSI). I am using HP tapes. The storage capacity is 12GB
    uncompressed,
    and 24GB compressed. When I backup my hard drive (lots of photos, text,
    etc), it
    will only write 18GB to tape, then say the tape is full and needs another.
    Is it possible,
    that the data is already in a compressed form and thats why I can only stuff
    18GB on
    the tape ?

    thanks for any ideas,
    Darryl



  2. Re: NT4 & backup program

    "Darryl" wrote in
    news:j-WdnSUYEtCbZyGiRVn-tw@news.ruraltel.net:

    > Greetings,
    > I am using the default backup program that comes with NT 4. I am
    > launching it from the command line with the hcn flag. My tape drive
    > is an HP Dat24i (which is SCSI). I am using HP tapes. The storage
    > capacity is 12GB uncompressed,
    > and 24GB compressed. When I backup my hard drive (lots of photos,
    > text, etc), it
    > will only write 18GB to tape, then say the tape is full and needs
    > another. Is it possible, that the data is already in a compressed form
    > and thats why I can only stuff 18GB on the tape ?


    You are correct. Tape drive vendors like to advertize a 2:1 compression
    ratio, but it depends entirely on the compressibility of your data.
    Files that are already in a compressed form, such as JPEG and ZIP, will
    not compress further. On the other hand some files will compress much
    more than 2:1 (text files full of spaces for tabular layout, for
    example). I typically get around 1.5 on a file server with all kinds of
    files in an unpredictable mix.

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    A L B E R T A Alfred Falk falk@arc.ab.ca
    R E S E A R C H Information Systems Dept (780)450-5185
    C O U N C I L 250 Karl Clark Road
    Edmonton, Alberta, Canada
    http://www.arc.ab.ca/ T6N 1E4
    http://www.arc.ab.ca/staff/falk/

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