size vs size on disk

[Dave]

I have winXP SP2 on a NTFS and I am wondering why is
there sometimes a large difference between a file or
folder size and the size on disk. I have several folders
with .java, text and .class files and the reported size
is as low as 1/4 of the reported size on disk.

Other folders with commercial software do not have a very
large difference, so why would there be a big difference
in the other files?

Thanks

 

[Tony Talmage]

Aye, that's correct.. typically one should not see a huge difference with
single files - no more than 4kb for an NTFS partition. However, if you get
properties for a folder with many small files, you will most likely see this
behaviour. For example, if I get properties on our courseware (6900 files
in 1100 folders), I see a huge difference in size due to the sheer number of
small html/asp files; I show 53.2MB, 72.9MB on disk. However, checking
properties of the courseware package shows a minute difference; only 1300
bytes.

So, I guess what I'm saying is that nothing can be done about the difference
between the file size and the used clusters, but I hope I've explained well
enough to answer the OP's question.

 

[Alex Nichol]

I have winXP SP2 on a NTFS and I am wondering why is
there sometimes a large difference between a file or
folder size and the size on disk. I have several folders
with .java, text and .class files and the reported size
is as low as 1/4 of the reported size on disk

They have probably been compressed - if a file or folder name is shown
in blue, that is what has happened. Otherwise such a discrepancy
would indicate a file with only about 1K of data, taking a full 4 K
cluster on an NTFS disk. You might get a bigger effect on a large FAT
32 one; big clusters