New securely erased drive not empty according to Disk Utility Erased 32GB USB flash storage with Disk Utility's "Secure Erase" feature, one pass of zeros. Disk Utility now reports that there is only 26GB of my drive available. Not sure what is going on here, but I'd like to know where my 6GB of space went.

Update: Zeroed the drive using DD, created new partition using Disk Utility, resized the partition and created a new one. It appears that for each of my partitions created, 6GB of the available space is taken up by something. The hidden files (Trashes, Spotlight, and fseventsd) do not account for this usage. This is really baffling and annoying, and any clue as to what is happening would be very appreciated.

Edit: Pictures to clarify:

Problem occurs on more than one drive, I think it has something to do with either journaling or local time machine backups.
This is likely coming from one or two things (or both).

Partitioning a disk, any disk, takes up drive space. In the megabyte range it is not even noticeable. In the gigabyte range it can be a substantial byte (sorry...) out of the drive. 

Also computer makers and Drive/RAM makers often calculate bytes differently. O/S companies (Apple, Microsoft, etc...) call 1K 1024 bytes. Drive/RAM makers call 1K 1000 bytes. If you do the math it looks like you "lost" a lot of space when it is just different conventions.

Also formatting a drive will map out bad blocks. So depending on how many bad blocks there are that can reduce the size of the formatted volume as well.