What happens to that information? How can it be destroyed?
In: Technology
It depends what kind of memory. I will go over several types:
RAM: RAM memory stores data as electrical charges. These charges need to be “recharged” very frequently (a few dozen times a second). If the electrical supply is interrupted, the charge in the memory will leak out, and the information will be erased. The information can also be erased by purposefully draining the charge out of certain memory locations using an “erase” command.
Hard Drives: Hard drives store data as magnetized particles embedded in a spinning disk. A “read/write” head moves above the disk, and applies a magnetic field that can change the magnetization of the particles. When you erase a file, the write head overwrites the data (pattern of magnetic particles) with other data.
Flash Memory: Many computers have SSDs with flash memory instead of hard drives. Like RAM, SSDs store data in the form of electrical charges. Unlike RAM, these electrical charges don’t drain quickly, so you can leave a flash drive for months or years without power and still have the data. In order to erase data, you send a command to the flash memory to intentionally drain the electricity from the memory locations you want erased.
When you delete a file on your hard drive or SSD, often the file isn’t actually deleted. Your drive keeps an index of all the files on the drive, and where they are stored. When you delete a file, the drive deletes the index entry for that file. The data may still be on the disk, until that area of the drive is over-written with a new file. This is how data recovery programs work, they ignore the file index and hunt for evidence of old files on the disk. You can deliberately delete a file by manually over-writing the region where the file was stored with other data. Drive-wiping programs erase disk by writing random data to the entire drive to make sure all the old data is gone.
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