Data Destroyer
Testing purge speed

The time taken to purge a file depends mainly on its size, the number of overwrites performed and the disk write speed, but also on other factors such as the CPU speed, the extent to which the file is fragmented on the disk, and whether the operating system is also doing other things (such as writing to the paging file).

Clicking on Test purge speed brings up a drive selection window (unless there is only one disk drive connected).

The test involves writing up to 20 dummy files (of varying size, from 50 KB to 128 KB) to the selected drive. These files are then purged (using the currently specified purge type) to test the purge speed for that drive so as to get an estimate of purge time required for other files.

After the test the purge speed is displayed, and estimated times are given for files of various sizes.

A precise estimate of the time required for purging many files is not possible because the purge speed is much larger when purging a single large file than it is when purging many small files with the same total size. Thus when multiple files are being purged Data Destroyer calculates an adjustment factor to be applied to the measured disk purge speed. The resulting estimate is necessarily imprecise, and the actual time can be from a half to twice the estimate, but at least it gives you some estimate, which is better than none.

Next: Purging a single file
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