This may well be a dumb question but my google-fu has not been able to solve it so far, so here goes...
I've had a 250GB external USB HDD (Acomdata, real size ~232GB) for quite some time that was used on both a system with XP and a Macbook, which I no longer have. It was originally formatted as FAT32.
I decided that before bringing it "back into commission" for backup purposes, I'd run Darik's Boot and Nuke (DBAN) to do a secure format outside of Windows. Problem is that DBAN doesn't like my laptop (non Mac) and the Linux kernel kept "panicing". Windows didn't recognize the drive after the botched format (I thought it killed the drive, but alas, I just had to go inside disk manager and create the RAW partition)
Vista doesn't like to format drives bigger than 32GB as FAT32, so I did a NTFS format (full, not with "quick" checked) with default cluster size. It worked but I see that there is now 96.8MB of used space and something like 14 files that I can't see (drive, properties). I have hidden files/folders, system folders all set to let me view them, and all I see is a $RECYCLEBIN and a System Volume Information folder. CHKDISK with all options shows no errors in log.
I used Heidi Eraser on both current files and free space and it still left 96.8MB as used.
Is this something to do with the NTFS formatting of the drive, or is there some sort of bigger problem? With indexing turned off, I would have thought it would use ~0MB of space.
The full format doesn't do anything different than reading the entire surface; it does not zero-write your disk its only useful for discovering bad sectors. Use quick format it will be the same.
Any NTFS partition will use space for its journal, which is about 100MB i think. So if a partition is 100GB and you put a filesystem on that, the usable space will always be less than 100GB even with zero files on it. Where else does it store information about the filesystem?
100MB is nothing compared to hundreds of gigabytes of space. But if you insist; FAT uses less space as its unreliable since it has no journaling at all.
as to your question this just came up in another thread on a win7 system it was boot files for system recovery. Now I was under the impression this was new to win 7 but it may have applied to vista as well.