Hey guys what is the difference between empty trash & secure empty & if I secure empty the trash will it affect my SSD? It certainly takes longer.
simple delete just really 'unlinks' the file from directory/folder/filesystem entries, but does not really delete the file, just referencess to it/ways to access it.
secure deletion actually overwrites the deleted file with random data before doing the above. I don't recall if secure empty trash does a single pass over the file or 7. The US government/DOD/etc. generally requires a 3 pass overwrite to consider data to be truly wiped.
So, it's up to you - use normal delete, and it's not difficult to buy or write a program that can recover the original files, but if you aren't worried about the laptop or data winding up stolen or in someone elses hands, or if you are constantly adding and deleting data and keep your drive near capacity, it's not that big of a deal.
A single pass or more of random overwrite is going to ensure most available programs (that I'm aware of, anyways) are not going to be able to recover your deleted data at all. A single pass *may* be recoverable by data recovery experts charging insane $, and multiple passes makes recovery *almost* to possibly entirely impossible regardless of who is trying to recover it.
Obviously, a simple directly/file 'unlink'/entry removal - nearly instant, and any of the overwrite/secure methods are significantly longer, and will be longer based on the number of passes made.
Can anyone confirm the number of passes made by 'secure empty trash'? It' using 'srm' under the covers, so easy enough to test I suppose..better would be if there's a way to change the number of passes made by secure empty trash - anyone know a setting or plist entry on that one?
Oh, PS - secure empty trash will be doing significantly more writes to a disk (or SSD) than normal deletion does. SSDs are generally rated at least years of usage, but it depends on how accurate vs how much you're writing to it, up to you - you can look up the numbers of writes estimated for specific SsDs before failure if you'd like.