(1) "Physical deletion" is a concept when computers process data.
The opposite of physical deletion is logical deletion. Logical deletion is to mark the data to be deleted for deletion. Logically, the data is deleted, but the data itself still exists! Physical deletion, on the other hand, completely removes the data from the medium.
For example, when a file is deleted on a disk, during the deletion operation, only a delete mark is made in the file allocation table FAT, but the file data in the disk sector still exists, which is logical deletion! Physical deletion means that some software uses some specific algorithms when deleting, and repeatedly reads and writes the sector where the deleted file is located, so as to achieve the purpose of complete deletion. As for writing files, the allocation of sectors is random. Logically deleted files are easy to recover while physically deleted files are difficult to recover!
(2) How to implement logical deletion?
I will introduce this tomorrow (๑• . •๑)