"Bruce Chambers" wrote:

> Abel Chan wrote:
> > Hi all,
> >
> > I have a Win2K server.  It’s C: drive is in FAT.
> >
> > When I go to C:\WINNT properties, it shows the Size is 1.81 GB and Size on
> > disk is 2.69 GB. 
> >
> > Could you tell me the difference between Size and Size on disk?  2.69 GB
> > seems to be the actual disk space used, right?
> >
>
>
>     "Size" refers to the actual total of the sizes of all of the individual
> file sizes, while "Size on Disk" refers to the total amount of disk
> space occupied by those files.  The difference is because some of the
> files do not occupy an entire cluster.  For instance, a 1 Kb file is
> occupying a single 4 Kb (or 8 Kb or 16 KB) cluster.  Clusters cannot be
> shared by different files, so there will always be some wasted space
> whenever a file doesn't completely fill a cluster.  If there are a lot
> of small files, the wastage becomes quite noticeable.
>
>     You've said that the partition is using the FAT file system, but I
> assume that you meant FAST32, as FAT partitions are very limited in
> size.  While FAT32 allows much larger partitions, it is still quite
> wasteful of space, if the partition exceeds 8 Gb in size.  This is due
> to FAT32's designed cluster sizes:
>
> Volume Size        FAT16         FAT32        NTFS
>             Cluster Size    Cluster Size    Cluster Size
> 2 GB–4 GB        64 KB        4 KB        4 KB
> 4 GB–8 GB        Not supported    4 KB        4 KB
> 8 GB–16 GB        Not supported    8 KB        4 KB
> 16 GB–32 GB        Not supported    16 KB        4 KB
> 32 GB–2 terabytes    Not supported    32 KB?        4 KB
>
>     So, on a modern hard drive with large partitions, you can see how a
> small file can easily "consume" a great deal of disk space.  The same
> thing occurs on an NTFS partition, of course, but to a much small
> extent, due to NTFS's smaller cluster size.
>
>
>
>
> --
>
> Bruce Chambers
>
> Help us help you:
> http://dts-l.org/goodpost.htm
> http://www.catb.org/~esr/faqs/smart-questions.html
>
> You can have peace. Or you can have freedom. Don't ever count on having
> both at once. - RAH
>

"Abel Chan" <awong@newsgroup.nospam> wrote in message
news:5DA30AE5-E443-40EA-96E8-6C11708F9AAD@microsoft.com...
> Hi all,
>
> I have a Win2K server.  It's C: drive is in FAT.
>
> When I go to C:\WINNT properties, it shows the Size is 1.81 GB and Size on
> disk is 2.69 GB.
>
> Could you tell me the difference between Size and Size on disk?  2.69 GB
> seems to be the actual disk space used, right?
>
> On another Win2K servers which has NTFS on its C: drive, the Size on disk
is
> greater than Size.  This is confusing.  ?
>
> Is this because of FAT and NTFS file system issue?
>
> Thanks.
>
> Abel Chan
>

"Colon Terminus" wrote:

>
> "Abel Chan" <awong@newsgroup.nospam> wrote in message
> news:5DA30AE5-E443-40EA-96E8-6C11708F9AAD@microsoft.com...
> > Hi all,
> >
> > I have a Win2K server.  It's C: drive is in FAT.
> >
> > When I go to C:\WINNT properties, it shows the Size is 1.81 GB and Size on
> > disk is 2.69 GB.
> >
> > Could you tell me the difference between Size and Size on disk?  2.69 GB
> > seems to be the actual disk space used, right?
> >
> > On another Win2K servers which has NTFS on its C: drive, the Size on disk
> is
> > greater than Size.  This is confusing.  ?
> >
> > Is this because of FAT and NTFS file system issue?
> >
> > Thanks.
> >
> > Abel Chan
> >
>
> That's because the smallest amount of data that can be written to the disk
> is 1 "cluster". Size on disk is always going to be larger than Size unless
> Size is an exact multiple of cluster size in which case they'll be
> identical.
>
> See this article for how default cluster size is determined:
> http://support.microsoft.com/default.aspx?scid=kb;en-us;140365
>
> See this article to see how to find out your cluster size(s):
> http://support.microsoft.com/default.aspx?scid=kb;en-us;245436
>
>
>
>