SSD storage is fundamentally very different from how HDD works, how sectors are mapped and are freed for reuse, and particularly around how thr floppy-disk-era sector overwrites and related practices simply serve to further wear the device for no tangible benefits. All freed blocks are necessarily erased, as part of preparing that same storage for re-use. Course, that'll eliminate everything else on the disk.With SSD storage and its use of TRIM, all deletions are secure. Or whatever disk held the file you want to eliminate. Really, the only way to make sure that any disk block that ever held your file would be to

That still doesn't catch it all - if the file you're shredding has been defragged, and some other file ended up occupying a block that used to hold the file, before you get around to shredding all the slack space on the disk, then that block is spared the 35 rounds of Gutman goodness. Then you would securely delete this file, that has just occupied nearly all the empty space on your disk. The only way I can think of to deal with this (maybe someone else can come up with a better way) is to write a bunch of data to the disk, and let the entire drive fill up completely. Then you run srm or similar on it, and it erases the new location 35 times with random data, but the old sectors it used to occupy are left alone. The file might have moved all over the drive in the past.įor example, if you defragment the disk (which OS X does on the fly, without you needing to tell it), the file will move to a different part of the disk. The problem with any secure deletion utility, is they only erase the parts of the HD that the file occupies now.

Reverse secure empty trash mac