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Wipe free space for Hdd/SSd Drive


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#1 OFFLINE Kpdatruth

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Posted 17 April 2011 - 03:10 AM

I've been doing some reading, the opinions on the subject left me with doubt. I wanted to know if it would be safe for me to use the wipe free space option on a Hdd/Ssd drive, and if I should use the MFT free space option. Also, what is the necessary level for cleaning. Will 1 pass be enough?

#2 OFFLINE Augeas

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Posted 17 April 2011 - 06:06 AM

Do you mean just SSD? Safe? Well it's certainly undesirable, and probably pointless. WFS and WMFT are essentially processes run by a file system written for hard drives, and would not, in my opinion, achieve what is intended on an SSD. I wouldn't even contemplate running it, and certainly wouldn't run it unless you have TRIM enabled. Even then running it once would be shortening the SSD's lifespan a little, running it regularly would be shortening it a lot.

Overwriting an SSD cluster causes a new cluster to be written and the old one flagged as invalid. So the principle of WFS and WMFT is compromised. On an HD you can overwrite a specific cluster, on an SSD you can't. Furthermore the process of WFS and WMFT involves creating and deleting files. Deleting files is a file system operation, without TRIM SSD's don't know or care about file deletion and will continue to maintain these clusters as valid.

In any event the SSD will probably take care of obsolete data by its own routines better than WFS or any O/S or user attempt to overwrite data. Invalid clusters will be cleared by SSD cleanup routines (garbage collection) and there is some talk of SSD internal routines reading NTFS bitmaps and clearing unused clusters automatically. How much truth there is in that I don't know.