Unit 1: Introduction to Operating System

 Function, Evolution, and Different Types of Operating Systems:

Question: What is the primary function of an operating system?

Answer: The primary function of an operating system is to manage and coordinate computer hardware and software resources to provide a stable and efficient computing environment. 

 

Question: How has the evolution of operating systems progressed over time?

Answer: Operating systems have evolved from simple batch processing systems to modern, user-friendly interfaces, incorporating features like multitasking, multiuser support, and graphical user interfaces (GUIs).

 

Question: Name two different types of operating systems and highlight their key characteristics.

Answer: Two types of operating systems are single-user operating systems (e.g., MS-DOS) and multi-user operating systems (e.g., Unix/Linux). Single-user systems are designed for individual users, while multi-user systems support multiple users concurrently.

Desirable Characteristics and Features of an Operating System:

Question: What are some desirable characteristics of an operating system?

Answer: Desirable characteristics include reliability, security, portability, scalability, and a user-friendly interface.

 

Question: How does the user interface contribute to the usability of an operating system?

Answer: A user-friendly interface simplifies interactions between users and the operating system, enhancing ease of use and accessibility.

Operating Systems Services:

Question: Identify two types of services provided by operating systems.

Answer: Operating systems provide process management services (managing running programs) and file management services (organizing and accessing data on storage devices). 

 

Question: Differentiate between services provided through commands and system calls.

Answer: Commands are instructions entered by users, while system calls are programmatic requests to the operating system for specific services.

System Calls and Low-Level Implementation:

Question: Why do we need system calls in operating systems?

Answer: System calls provide a controlled interface for user programs to request services from the operating system, ensuring proper execution of privileged operations. 

 

Question: How are system calls implemented at a low level?

Answer: System calls involve a transition from user mode to kernel mode, achieved through a software interrupt or trap instruction, allowing the program to enter the kernel and execute privileged operations.

Portability Issues:

Question: What are the portability issues associated with system calls?

Answer: Portability issues arise when system calls are platform-dependent, making it challenging to execute the same code on different hardware architectures or operating systems.

Operating System Structures:

Question: Name three types of operating system structures.

Answer: Monolithic, layered, and microkernel are three types of operating system structures. 

 

Question: How does modularity contribute to the design of operating systems?

Answer: Modularity enhances flexibility and maintainability by breaking down the operating system into independent modules, making it easier to understand, update, and debug.

Note: These questions and answers cover key aspects of the provided syllabus, offering a foundation for understanding the function, evolution, services, and structures of operating systems.