What is a Hard Disk? How Is Data Stored and Retrieved? What is Disk Formatting ( Physical Disk Formatting and Logical Disk Formatting )? What is a File System? What are Partitions? Why Use Multiple Partitions? How a Computer Boots? In this quick introduction to hard disks, there is a very useful warning that people would have to never forget: since formatting the disk deteriorates the properties of the magnetic material, format the disk when it is necessary only that means there is no way other than formatting.