INT 13h is like a secret code that your computer uses to talk to your hard drive or other storage devices, like flash drives or CDs. Kind of like how you need a special password to get into a secret club, your computer uses the code INT 13h to access the secret world of storing and retrieving information from these devices.
The code INT 13h tells your computer to talk to the BIOS (Basic Input/Output System), which is like the computer's brain. The BIOS controls things like turning the computer on and off, and controlling the keyboard and mouse. When the code is entered, the BIOS takes over and talks to the hard drive or other storage device using a language it understands.
It's important that the computer knows how to talk to the storage devices because it needs to be able to read and write to them in order to store and retrieve your files and programs. Without INT 13h, your computer wouldn't be able to do this, and you wouldn't be able to save your work or use any programs or apps. So, in a way, it's a super important code that helps your computer function.