Storage space on disk drives is divided into fixed size blocks called
clusters. Typically clusters are 4096 bytes, 8192, 16384 etc. depending on
the size of the hard drive.
Size of files is variable. A file has to fit into a cluster that is as big
as the file or bigger. Therefore a 1000 byte file will take up a 4096 byte
cluster on disk (the wasted 3096 bytes is known as slack space).
Statistically on average each file on disk wastes half a cluster of space.
Typical installation of Windows with 50,000 files wastes 200MB on 8GB
partition, 400MB on 16GB, 800MB on 32GB etc.
> When I right-click on a folder in the explorer and choose
> the properties, the system told me to number for the size
> (or space, because I'am on a french version) the folder use.
> He give me the size (space) and size on disk (disk space ?).
> When I've got a difference, from where come the difference ?
> Thank you