So i was enjoying some down time for myself the other night taking a nice warm bath and letting my mind wander when i suddenly recalled a time when i worked at a research station and some idiot managed to somehow delete over 3000 excel spreadsheets worth of recently collected data. I was charged with recovering the data and scanning through everything to make sure it was ok and nothing deleted…must have spent nearly 2 weeks scanning through endless pages…and it just barely dawned on me to wonder…exactly…how the hell do data recovery tools collect “lost data”???
I get like a general idea of like how as long as like that “save location” isnt written over with new data, then technically that data is still…there???? I…thats as much as i understand.
Thanks much appreciated!
And for those wondering, it wasnt me, it was my first week on the job as the only SRA for that station and the person charged with training me for the day…i literally watched him highlight all the data, right click, and click delete on the data and then ask “where’d it all go?!?”
In: Technology
An harddrive is like a paper notes. You won’t cut a hole into it to erase content, because if so, you will also need to tape paper back.
So physically, the paper will always exists.
Then as for it contents, it is up to you to organize it and interprete it as you want.
You may see emptyness everywhere, but for a computer, those emptyness are still something – like (TLDR) they may see the space characters used in between word on the full page instead of emptyness. You don’t create data or delete data [physically] on an harddrive. If you prefer, see it like electrical switches. They may not be wired, but they will always exists.
That paper will be read by you to someone else, so only you need to be able to read it, but not the other guy.
Let create our own file system to manage our data on that paper note: A valid block (and existing block) of data on your page always start with a capital letter and end with a dot. If you see a dot followed by a non capital letter then it is free space until the next capital letter. So, basically how they teach you how to write a sentence.
So you start writing sentences on your page, 5, then 10 sentences. Then you figure out you don’t need the 3rd sentence anymore. You could erase that sentence and move everything after to clear the emptyness so it looks great.
That will take sometime. And, for a computer, reading data is hidden from the user. So why bottering to look nice when you just want to be fast so the user like you?
You remember our rules from above? They have been made to be fast.
Instead, you will just lower the first capital letter of the sentence you want to “erase”.
So later one, when you will read that paper, you will read the first sentence. After the dot you will start reading aloud only on the next capital letter. The next capital letter is on the 3rd sentence.
So for the user, the 2nd sentence doesn’t exists. Yet, it is still on your page.
If you need to write something, you will look for free spaces by looking for those “invalid” block of data – those invalid sentences.
If you want to recover a sentence, you will recreate, yourself, how our storage system work, but will basically swap out the rule of what is “sentences to read” with “what sentences to ignore”.
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