Understanding Operating Systems Concepts

Operating systems are fundamental to computer science. Understand key concepts for exams and interviews.

What is an Operating System?

An OS is system software that manages hardware and software resources.

Key Concepts

Process Management

• Processes and threads
• CPU scheduling algorithms
• Inter-process communication

Memory Management

• Virtual memory
• Paging and segmentation
• Memory allocation

File Systems

• File organization
• Directory structures
• File permissions

CPU Scheduling Algorithms

First-Come, First-Served (FCFS)

Simple but can cause convoy effect.

Shortest Job First (SJF)

Optimal average waiting time but requires prediction.

Round Robin

Each process gets equal time quantum.

Priority Scheduling

Higher priority processes run first.

Virtual Memory

Virtual memory allows programs to use more memory than physically available:

Physical Memory | Virtual Memory
   4 GB     |     8 GB

Benefits:

• Run larger programs
• Multiple programs simultaneously
• Efficient memory usage

Deadlocks

Deadlock occurs when processes wait indefinitely:

Four Conditions:

1. Mutual exclusion
2. Hold and wait
3. No preemption
4. Circular wait

Prevention Strategies:

• Resource allocation algorithms
• Timeout mechanisms
• Deadlock detection and recovery