Why deleting data is too slow ?

Question

Can anyone please tell me that if deleting data is just marking of data as deleted in File Allocation Table then why it took too much time to deallocate data ??

It must be very fast. OS doesn't even have to touch any data, just mark data as deleted

How how can I read data from hard disk using C which is marked as deleted??

Answer 1

Martin Taylor
Does now mine question is better??😅😅

And now OS doesn't use FAT anymore ?

And files are saved for sequential access in hard disk.

Answer 2

Martin Taylor
I wants to learn all of these low level stuff

From where should I start ?
From where I can get proper information ?
Please help ☹️☹️

Answer 3

Martin Taylor
Should I apply for computer science or for electric engineering in university

After almost 3 months I will join university

Answer 4

Martin Taylor If modern Operating Systems doesn't give much low level access then I'm ready to use old operating systems and make my own simple operating systems to practice and learn.
Thanks you