>>But how are you going to actually change the file system? You can't merely specify a cluster size for a single file. It's a disk wide change and cannot be easily controlled.
>
>I don't want to change anything. All I want to do, with my utility, is report how much space is used. Let's say it is obvious to the user that his cluster size is, e.g., 4 KB, but the program shows information based on 32 KB clusters (because of the FAT32 problem, or because of a network connection), the user can change from "Auto-detect" (the default) to "4 KB".
>
>Also, if the user gets information for a folder on a local NTFS partition (say, 4 KB clusters) and wants to know how much space the files would use on a FAT32 partition of 20 GB (16 KB clusters, if formatted without the "/Z:nn" option), the user can change the auto-detected 4 KB to 16 KB.


Umm, what would you say to a base unit of allocation of 512 bytes? That's typical of small (I think the border is 32 or 64GB) NTFS partitions.