Briefly explain the functions of operating system.

An Operating System (OS) is system software that acts as an intermediary between the user, application programs and computer hardware. It manages resources and ensures smooth, secure and efficient operation. Examples: Windows, Linux, macOS.

Major functions:

1. Process Management: Creates, schedules and ends processes. Decides which task gets CPU time and for how long. Handles multitasking — e.g., typing in Word while music plays and printing runs in background.

2. Memory Management: Allocates RAM to each program, keeps track of free and used memory, and uses virtual memory (part of hard disk) when RAM is full. Also protects one program from overwriting another’s memory.

3. File Management: Organizes files in folders/drives, controls creation, naming, copying, deletion, searching and access permissions. Example: NTFS in Windows allows read/write permissions per user.

4. Device Management: Communicates with all input/output devices through drivers using spooling and buffering. Example: print spooler lets you keep working while printer prints queue-wise.

5. Security and User Management: Creates user accounts, passwords and access rights. Prevents unauthorized access and protects data from viruses and misuse. In offices, admin, manager and clerk get different access levels.

Without an OS, the user would have to control hardware manually with machine code — the OS hides this complexity and gives easy GUI/CLI to work with.