How does mobile phones memory work?

[Aesteras]

Hi, everyone!
With all the news lately about mobile phones leaks, I was curious about how mobile phones work.
I know the latest case had little to do with the phones memories, and it was all because of a security flaw from a cloud-based storage service, but anyway, it got me into thinking.
So, how does the storage system of a mobile phone (be it MicroSD cards or internal memories) work?
Is it similar to the way hard disk drives work for PCs?
If you delete a file, is it gone for good or could someone with access to your phone retrieve it someway?
And if so, is there anything you can do to prevent that from happening (like wiping the memory, etc.)?

 

[riksweeney]

Phones store data in the same way as computers do. When you take a photo or install an app, the phone will look for an unused area in the file system and place the data there.

When a photo, app, music or other data is removed from your phone, the file system will return to the area that the data has been placed and mark that area as unused, freeing up the space for other data.

In reality, the data is still there, but as far as the phone is concerned, the space that it used to occupy is empty. You can use software to retrieve that data, provided that it hasn't been replaced, partially or fully.

You can certainly get software that will scramble the empty space on your computer/phone/whatever so that old data isn't retrievable, but personally, I prefer that I can still retrieve the data as I've had problems in the past where I've had memory cards corrupt on me, or in one case, a jerk from HP wiped my HDD even though the screen just needed replacing.

 

[Aesteras]

I see, that's good to know.
Thanks for such a detailed answer!