Slack
Slack is a little program I wrote for myself. I wanted to know how much disk space was wasted because of cluster size.
Synopsis
slack [-h|-?] path
Description
A cluster is the smallest size you can allocate on a disk, and files always occupy one or more clusters. Even a one-byte file occupies an entire cluster, which can easily be 4k, 8k or larger. So on a file system with 4k cluster size, a one-byte file produces 4095 byte of slack. If you have many very small files, the slack can be rather high. Slack calculates the slack and displays it.
The program outputs the slack for the directory you specify and its subdirectories, as well as some other information. If you call slack without parameters, it will use the current directory.
Here you can see it in action, in my Windows directory (note that I use a German Windows, where . is the thousands separator, and , is the decimal separator — it may use a different output format on your system, according to your settings).:

If you want help, you can specify -h or - ? as parameter.
Disclaimer
Slack is freeware. All rights are reserved. Its code is provided as is, expressly without a warranty of any kind. You use it at your own risk.
I hope this code is useful to you. If you use some of it, please credit me. If you modify or improve the program, please send me the modifications.
I may improve or enhance slack myself, and I will try to post changes here. But this is not a promise. Please don't request features.
Rudy Velthuis

Copyright © 2000, 2007 by Rudy Velthuis
