It has many functions:
1. Provides User
Interface, connection between the user and the computer hardware.
2. Does memory
management and file management. For example, decides when
RAM should run and when it can take data from HDD.
3. Does
Peripheral Management, coordinates Basic Input and output system (BIOS). It
controls the peripherals through device drivers that act as translator between
the devices and the computer.
4. Provides
Security by preventing unauthorized access, requiring usernames and
passwords.
5. Allows Multitasking.
6. Allows
Networking by sharing data among the devices.