WinDirStat

If you want to get a quick overview of where data is stored on a hard drive or network directory, and what types of files are present, try the free utility, WinDirStat, available at: https://windirstat.net/ .

As you can in this screen grab, WinDirStat shows the percentage of a drive's data that individual folders hold. So the 'My Documents' folder has 79.5% per cent of the data on the C drive, and the 'My Music' subfolder has 88.2% of the data in that 'My Documents' folder.

The graphic at the bottom of the screen shows at a glance that by far MPEGs are the most common file type on the C drive, by referring the color code list on the upper right.

Difference in File Size and File Size on Disk

When copying files from place to place in Windows you may have noticed that there is a difference between the size of the files in a folder and what Windows calls the 'Size on disk'.

The reason for this is that data is allocated in Windows in clusters, and each cluster must take up a certain number of bytes. Each file no matter how many individual bytes it has, must take up a fixed number of clusters. This leads to wasted space. For example a file that is 13.4 KB (13,753 bytes) will take up 16.0 KB (16,384 bytes) when the cluster size is 4096 bytes. You need four 4096 clusters to contain all of the data. You can determine the number of clusters taken up by a data set on your PC by using the Cluster Size Calc utility, available for download here. In this screen grab we can see how the utility calculates possible cluster sizes for the C:\FooFolder directory for which the Windows properties are shown above. We can see that since the size of the files in the folder is 81,550,109 bytes and the size on the disk is 81,625,088 bytes, with a difference of 74979 bytes, the cluster size must be 4096 bytes.

Dynamic Link Library Files

Dynamic Link Library files (.dll files) are used so different programs in Windows can share the same functionality. Normally these would be systems files on one's de-NIST list - non-responsive electronic files to be removed for the data set for review. However it is possible to view the contents of .dll files and see which functions they specify.

NirSoft's DDL Export Viewer can be downloaded here. It will generate a list of functions in each .dll file. Just a little Window into the obscure world of system files.