Only computers can decipher the information contained in a binary file.

Operating systems take great care to ensure that each block of a file is written to a new, unwritten block of the storage medium in a sequential order. When working with magnetic disks, why is this step so crucial?

When a file is opened for the first time, it is the responsibility of the operating system to ensure that the file's blocks are written to the disc in the right sequence. Is there anything special about magnetic discs that makes this topic deserving of such a great lot of attention? Would it make a difference or not if, rather than traditional hard drives, solid-state drives (SSDs) were used? - What might possibly be causing this?

There is a finite number of primary partitions on a hard disc.