What is the function of the hard drive disk?

Answer 1

used for longer term storage of data

Answer 2

The primary function of the Hard Disk Drive in a computer is to store all the computers information, most importantly, the operating system.

It then is used to retrieve information at any given time. When you hear your Hard Drive making noise, this is because the magnetic disk inside it is spinning, and it's seeking requested information.

The information on your Hard Drive can also be loaded onto the RAM (Random Access Memory), so it won't always have to be pulled directly from the hard drive, which is a slower process.