WipeFS erases unused space on hard disks, USB flash drives etc, to prevent the recovery of deleted files. Any data which still resides in that unused space, albeit marked 'free', can be properly and securely deleted by overwriting it. As you may know, simply deleting a file does not actually delete the content of the file. Instead, the space that file occupied on the disk is simply marked as being 'free' and may exist for a long time until another file is allocated that space (or part of it).
Simply check the drive(s) you want to work on, the number of passes you want to perform (see Preferences) and click the "Start" button.
When wiping begins, you are shown the following information:
• The name of the volume whose free space is currently being wiped.
• The current block (blocks are files the application writes to your volume, they are temporary and deleted after wiping has completed successfully).
• The current pass of the block (see Preferences), if applicable.
• The value being used to overwrite the data (see Preferences).
• The number of remaining blocks yet to be made.
• The total progress.
The time it takes to wipe a volume depends on the size of the volume, the speed of your Mac (and amount of RAM), and how many passes you specify. Obviously, 8 passes will take eight times longer than 1 pass.
A quick test showed that an iMac with 2.66GHz CPU, 4GB DDR3 RAM would wipe 517GB in 3 hours 22 minutes (using one pass). So three passes would take about 10 hours.
When wiping the free space on a volume you will be asked to select a folder in which this app can store temporary files. You must have read/write permissions for the chosen folder.
The files created by this app will be cleaned-up after the free space has been successfully wiped or the process is aborted using the "Stop" button.
In the event the temporary files created by the application are not deleted, select the drives above and then click the "Clean up" button. You will then regain any lost disk space. If no temporary files are found, nothing will happen, if there are temporary files deleted you will be told how many were deleted.