🖥️ Functions of Operating System — Detailed Explanation

1️⃣ Resource Sharing (Resource Management)

An Operating System manages all hardware resources and shares them among multiple users and programs so the system works efficiently.

🔹 CPU Scheduling

CPU can run only one process at a time (per core). OS decides which process runs first and for how long. Uses scheduling algorithms like FCFS, Round Robin, Priority. Goal: maximize CPU use and reduce waiting time.

🔹 Memory Management

OS controls the main memory (RAM). Allocates memory to programs when they start. Frees memory when programs end. Prevents one program from accessing another’s memory. Uses techniques like paging and virtual memory.

🔹 Device Management

OS controls all input/output devices. Uses device drivers to communicate with hardware. Keeps track of which process is using which device. Handles device queues and access order.

🔹 File System Management

OS organizes data into files and directories. Handles file creation, deletion, read, write. Maintains file permissions. Manages disk space allocation.

2️⃣ Process Management

A process is a program in execution. OS manages the full life cycle of processes.

🔹 Process Creation & Termination

OS creates a process when a program runs. Assigns process ID, memory, CPU time. Terminates process after completion or error.

🔹 Process Scheduling

When multiple processes are ready, OS chooses which runs next. Maintains ready queue and waiting queue. Supports multitasking and multiprocessing.

🔹 Inter-Process Communication (IPC)

Processes sometimes need to share data. OS provides methods like: Pipes Shared memory Message passing Ensures communication is safe and synchronized.

3️⃣ Input / Output Handling

OS manages all input and output operations between software and hardware.

🔹 Device Drivers

Special programs that act as a translator between OS and device. Example: printer driver, graphics driver. Without drivers, OS cannot control devices properly.

🔹 Buffering

Temporary storage area used during data transfer. Helps match speed difference between CPU and devices. Improves performance by reducing wait time.

🔹 Spooling (related concept)

Stores I/O jobs in queue (like print queue). Executes them one by one.

4️⃣ Security

OS protects system, programs, and data from unauthorized access and threats.

🔹 User Authentication

Verifies user identity using: Username/password OTP Biometrics

🔹 Data Protection

Protects files using encryption and permissions. Prevents data corruption and theft.

🔹 Access Control

Different users get different rights: Read Write Execute Example: admin vs normal user.

🔹 System Protection

Prevents malware and unauthorized system changes.

5️⃣ Networking

Modern OS supports communication between computers and devices.

🔹 Network Protocol Support

Implements protocols like TCP/IP, HTTP, FTP. Ensures proper data formatting and transfer.

🔹 Network Communication

Enables: File sharing Printer sharing Internet access Remote login Manages network connections and sockets.

🔹 Resource Sharing over Network

Allows shared folders and shared devices across network.

6️⃣ Error Handling

OS continuously monitors system for errors and handles them.

🔹 Error Detection

Detects hardware faults, memory errors, illegal operations. Checks system calls and I/O operations.

🔹 Error Handling

Takes corrective action: Retry operation Stop process Show error message

🔹 Logging

Maintains system logs. Records errors and events. Helps in debugging and troubleshooting.