File size changes on Vista file system?

Discussion in 'General Technical' started by ryanbuckner, Mar 20, 2007.

  1. ryanbuckner


    Mar 20, 2007
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    I have a strange situation that I'd like to see if anyone else has seen. Here's how the issue is replicated.

    1) Create a file in Office Word 2007 and save as 1997-2003 format -or-

    1) Save 1997-2003 file to a Vista machine

    2) Email the file to an XP machine

    3) Save to XP file system

    The file started out as 500KB when it was emailed and when it is saved to the XP file system it appears as 5MB. Please note:

    1) I saved the same file to an XP machine before emailing and it remained unchanged.

    Has anyone seen something like this?
    ryanbuckner, Mar 20, 2007
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  2. ryanbuckner


    Feb 20, 2007
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    Yes indeed. Usually this is down to the cluster size that the partition is formatted in, also it makes a difference if one system is FAT and the other NTFS, to try to explain take this example. A file is 40K in size and the cluster size is 4K theoretically there will be 10 clusters taken so the size reported is 40K, you transfer that to a FAT or other system with a typically 16K cluster size and it needs 2.5 clusters to store the information, you can't use the half cluster left (known as file slack) so the 40K file is reported as using 3 16K clusters which is 48K apparently a larger file, actually not just stored on a less efficient system.

    This only a simple explanation, not because I think it's the only way you'll understand it but because it's actaully far more complicated than that and too lengthy an example would get me lost never mind you. Basically it's not a concern and something quite normal. Sometimes if you save a complex archivelike a RAR file or a UHARC file the resulting difference can be quite alarming, just remeber the files are exactly the same size, it just takes more hard drive space because of the way it's formatted and how the system stores files.

    Hope you can get the general idea from this, it can be quite easy knowing why a thing happens but an entirely different thing trying to explain it.

    cyclic, Mar 21, 2007
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