Deletions query

[Joe Saponic]

Like many people I discard unwanted material and delete it later using Secure Empty Trash. A quicker way is to copy-paste the name of the folder or file you want to delete across to a new folder created in another directory or part of the hard drive, so that when you drag it across and it asks whether you want to replace it you just click 'yes' and maybe 20GB of sludge vanishes almost immediately. Someone told me this might not be the best way to go about it, though he failed to explain why to my satisfaction even though I'm not especially well versed in computer matters. Can anyone advise me on this? Seems like a much better solution than waiting hours for the trash to empty.

Thanks.

 

[h9826790]

Like many people I discard unwanted material and delete it later using Secure Empty Trash. A quicker way is to copy-paste the name of the folder or file you want to delete across to a new folder created in another directory or part of the hard drive, so that when you drag it across and it asks whether you want to replace it you just click 'yes' and maybe 20GB of sludge vanishes almost immediately. Someone told me this might not be the best way to go about it, though he failed to explain why to my satisfaction even though I'm not especially well versed in computer matters. Can anyone advise me on this? Seems like a much better solution than waiting hours for the trash to empty.

Thanks.

I am just a normal computer user. However, my understanding is when you replace the folder by another folder with the same name. What you do is just make the file system that can't locate the old files anymore, but those files still physically exist on your HDD. Lots of data recovery software can easily locate those files (by scan through the entire HDD) and recovery them (basically just register those data as a files in the OS again).

I another word, in the software point of view, the file is deleted. However, in the hardware point of view, the data still there. Therefore, as long as there is one software can revalidate those data. That deleted file will magically re-appear again in the file system (software side).

What secure delete is actually a write action, not delete action. It delete a file on the software side, but actually over write all the data with 0 on the hardware side. Therefore, it takes much longer to finish the "delete" action. However, since the data was basically destroyed in both hardware and software side, it's much much harder to recover the data.

SSD may be a little bit different, because once the files mark as deleted by the OS, TRIM will tell the SSD controller that those data is no longer required, therefore, GC will physically destroy those data and free up the cell for future write action. This is how SSD keep the write performance. So, assume you leave the computer switch on, and let the SSD idle for some time. Those "quick deleted files" may actually completely destroyed on both software and hardware world.

 

[Joe Saponic]

I am just a normal computer user. However, my understanding is when you replace the folder by another folder with the same name. What you do is just make the file system that can't locate the old files anymore, but those files still physically exist on your HDD. Lots of data recovery software can easily locate those files (by scan through the entire HDD) and recovery them (basically just register those data as a files in the OS again).

I another word, in the software point of view, the file is deleted. However, in the hardware point of view, the data still there. Therefore, as long as there is one software can revalidate those data. That deleted file will magically re-appear again in the file system (software side).

What secure delete is actually a write action, not delete action. It delete a file on the software side, but actually over write all the data with 0 on the hardware side. Therefore, it takes much longer to finish the "delete" action. However, since the data was basically destroyed in both hardware and software side, it's much much harder to recover the data.

SSD may be a little bit different, because once the files mark as deleted by the OS, TRIM will tell the SSD controller that those data is no longer required, therefore, GC will physically destroy those data and free up the cell for future write action. This is how SSD keep the write performance. So, assume you leave the computer switch on, and let the SSD idle for some time. Those "quick deleted files" may actually completely destroyed on both software and hardware world.

[doublepost=1464108396][/doublepost]Thanks for this. There's nothing unsavoury in what I'm deleting so I'm sure it's potential availability doesn't matter that much. However I'll go back to secure delete in view of what you say. Thanks again for the advice.

 

[mildocjr]

Terminal is pretty quick too.

rm -r -f /FolderToRemove

or if you want to play with the black hole of computers

mv /FolderToRemove /dev/null

 

[ActionableMango]

[doublepost=1464108396][/doublepost]Thanks for this. There's nothing unsavoury in what I'm deleting so I'm sure it's potential availability doesn't matter that much.

If the potential availability doesn't matter and you don't like the long delete times, why are you using secure erase?

In any case, Secure Erase isn't even available in El Capitan.

 

[Joe Saponic]

If the potential availability doesn't matter and you don't like the long delete times, why are you using secure erase?

In any case, Secure Erase isn't even available in El Capitan.

Read the post. I'm not using Secure Erase. I have. I'm not now. That's the point.

There is nothing untoward implied by using Secure Erase. It's a tool. It's there to be used and, until recently, I used it.

You might infer that I don't run El Capitan from these details. You'd be right.

Thanks for getting back to me.
[doublepost=1464164043][/doublepost]

Terminal is pretty quick too.

rm -r -f /FolderToRemove

or if you want to play with the black hole of computers

mv /FolderToRemove /dev/null

I appreciate the tip but I'm not that advanced in computer use as I make clear in the post. In any case I stopped playing with holes, black and otherwise, after a protracted and somewhat rancourous divorce.