IFD "wipe unused sectors" option

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geosiou
Posts: 5
Joined: Fri Mar 21, 2014 8:11 pm

IFD "wipe unused sectors" option

Post by geosiou »

I have backed up my entire HD drive (one primary partition) after a clean Windows 7 installation (+ drivers & updates). Since then, I installed a LOT of programs, but now I want to restore to the same hard disk.
Then I will install Office and backup again.
Should I also check the "wipe unused sectors" during the clean Windows restore? At first sight it seems that it shouldn't matter, but since the restore state would use less hard disk than the already used, wouldn't it leave the rest of the disk show as "used" (sectors), so a future backup (after Office) would result in a much larger image file?
What I mean: let's say I'm now using 100GB (out of 320GB) HD space. Then after the clean Windows restore (10GB) plus Office and other essentials (say another 10GB), will the rest 80GB (up to the previous 100GN used size) get detected as used in a future backup? Will the future backup be of 100GB image size?
And if yes, would the "wipe unused sectors" write zeros before the clean Windows restore, so only 10GB of data show as used in HD? Then add Office and essential installations of another 10GB and the HD usage will be only 20GB with the rest sectors zeroed and thus the final new backup will result in an only 20GB image file?...
TeraByte Support(PP)
Posts: 1644
Joined: Fri Aug 12, 2011 12:51 am

Re: IFD "wipe unused sectors" option

Post by TeraByte Support(PP) »

Used space on the partition is still used space regardless of whether or not unused space is wiped. If there is only 10GB of data in the file system then that's what would be considered for the backup (assuming you're not backing up unused sectors).
geosiou
Posts: 5
Joined: Fri Mar 21, 2014 8:11 pm

Re: IFD "wipe unused sectors" option

Post by geosiou »

Thank you for your reply!

Since my clean Windows restore will overwrite only 10GB of my 100GB used space (full of data) HD, and since the rest of the 90GB of previous used space will still be used space (with data on it), how will a future IFD back up not consider all 100GB of data need to be imaged?

(and no, I'm not backing up unused sectors - and don't know what this has to do since I'm talking about used sectors... The way I have understood is that if I was backing up unused sectors as well, the image file would be of 320GB size - the full HD size, wouldn't it?)
TeraByte Support(PP)
Posts: 1644
Joined: Fri Aug 12, 2011 12:51 am

Re: IFD "wipe unused sectors" option

Post by TeraByte Support(PP) »

The file system on the partition (NTFS, FAT32, etc.) is used to determine what is used space and what is unused. The 90GB of data would still be on the disk if you looked at the sectors (assuming not wiped), but the file system would show that space as unused and it wouldn't be backed up.

If you include unused sectors in the backup, the image file can be very large. The file size may be as large as the entire partition/disk (320GB, in this case), but would still include the entire area (used and unused space) even if it compressed to the size of the used data or smaller.
geosiou
Posts: 5
Joined: Fri Mar 21, 2014 8:11 pm

Re: IFD "wipe unused sectors" option

Post by geosiou »

Sorry for my late reply, but thank you very much!! I think I fully understood!
It's like when deleting files, isn't it? The sectors are marked as deleted, but the data is actually there, ready to be overwritten by new files.
(Maybe even better analogy; quick and full format...)
So, wipe is ONLY a matter of security; to avoid undelete software recover the data... I can't think of any other case one is willing to use it...
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