Lecture 02: System Calls and Operating System Structures

1. What are System Calls?
2. System Call Lifecycle and Examples
3. SOS Structures: Monolithic, Layered, Microkernel
4. Performance and Modularity Trade-offs
5. Summary and Q&A

Slide Deck

Key Takeaways

• System Calls serve as the secure interface between user applications and the OS kernel, enabling controlled access to hardware and services.
• OS Structure directly impacts performance, modularity, and fault isolation. The choice of architecture influences how the OS handles complexity and failures.
• Real-World Usage:
  • Linux uses a hybrid monolithic model — fast but extensible.
  • Microkernels (e.g., QNX, MINIX) are favored in embedded and safety-critical systems for their reliability and modularity.