UG S3 Operating Systems, First Internal Examination, August 2024

 Section A

Answer any 5 questions. Each question carries 2 marks.

1.      Define operating system

An operating system (OS) is a program that manages the computer hardware and provides a basis for application programs. It acts as an intermediary between the computer user and the computer hardware, optimizing hardware utilization and providing a user interface for executing programs.

2.      Write about evolution of OS

The evolution of operating systems is tied to the development of computer systems. Early systems included batch processing systems in the 1950s, time-sharing systems in the 1960s, and personal computer systems in the 1970s. Key milestones include the introduction of UNIX, the development of graphical user interfaces, and the rise of mobile operating systems like iOS and Android.

3.      What are the functions of OS?

The primary functions of an operating system include process management, memory management, storage management, device management, security and protection, and providing a user interface.

4.      What is Segmentation?

Segmentation is a memory management scheme that supports the user view of memory. A program is divided into segments, which are logical units such as functions, objects, or data arrays. Segmentation allows for more efficient and organized memory use by isolating different types of data and code.

5.      Explain demand paging

Demand paging is a memory management scheme where pages of a program are loaded into memory only when they are needed during execution. This reduces the amount of physical memory required and allows for more efficient use of resources.

6.      What is meant by page replacement?

Page replacement is a mechanism used in virtual memory systems to decide which page in memory should be swapped out when a new page needs to be loaded. Common page replacement algorithms include FIFO, LRU, and Optimal Page Replacement.

                                                                       (5 x 2 =10 Marks) 

Section B

Answer any 3 questions. Each question carries 5 marks.

7.      Write about are the components of a computer system

A computer system is composed of hardware, the operating system, application programs, and users. The hardware includes the CPU, memory, and I/O devices. The operating system manages hardware resources and provides services for application programs, which solve user problems.

8.      Write a short note on operating system user interface

The operating system user interface allows users to interact with the computer system. It can be a Command-Line Interface (CLI) where text commands are entered, a Graphical User Interface (GUI) where interactions are made through graphical elements, or a batch interface where commands are executed from files.

9.      Explain the concept of Virtual Memory

Virtual memory is a memory management technique that provides an "idealized abstraction of the storage resources that are actually available on a given machine" which creates the illusion to users of a very large (main) memory.

10.  Explain Optimal Page Replacement

Optimal Page Replacement is a theoretical page replacement algorithm that replaces the page that will not be used for the longest period of time in the future. It is used as a benchmark to compare the performance of other algorithms.

               (3 x 5 = 15 Marks) 

Section C

Answer any 1 question. The question carries 15 marks

11.  Explain System Calls & Types of System Calls

System calls provide an interface between a process and the operating system. They allow user-level processes to request services from the OS. Types of system calls include process control, file management, device management, information maintenance, communication, and protection.

12.  Explain Paging & Paging Hardware in detail

Paging is a memory management scheme that eliminates the need for contiguous allocation of physical memory. It divides the physical memory into fixed-sized blocks called frames and the logical memory into blocks of the same size called pages. Paging hardware includes the page table, which maps logical addresses to physical addresses, and the Memory Management Unit (MMU), which performs the address translation.

 

                        (1 X 15 = 15 Marks)