
Why do the Volume and Directory Panes Report Different Sizes?
The sizes that Baseline reports in the Volume pane, and the Directory pane are not identical.
The capacity/used/available figures in the Volumes pane are physical sizes.
The sizes reported in the directory pane for each file of folder are the sums of logical file sizes of the data and resource fork for the file, or for the files within a folder.
If you have a file containing five bytes, its logical size is five bytes. However its physical size will be considerably larger. On a machine with a 4K block size, the five bytes file actually uses 4 Kilobytes on disk (its physical size).
This accounts for part of the difference between the Volume and Directory pane figures.
Additionally, Baseline does not count the size of the directories themselves. A "directory" is really just a file that lists the files and subdirectories for the directory. These files take up space. The more items in the directory, the bigger the directory file.
Because directory sizes, in themselves, are not very informative, Baseline leaves them out.
Finally, Baseline can only scan directories to which you have read access. When run as a normal or administrative user, Baseline will not be able to scan other users files. See "How can I scan all of the files and folders on my hard disk?" for more information.
See also
How can I scan all of the files and folders on my hard disk?