THE OPEN UNIVERSITY OF SRI LANKA FACULTY OF ENGINEERING DEPARTMENT OF ELECTRICAL AND COMPUTER ENGINEERING BACHELOR OF TECHNOLOGY EEX5235 – OPERATING SYSTEMS - TMA02 Academic Year – 2022/2023 Answers to this assignment should be uploaded to the given link in Moodle on or before the given due date. Hard copies will not be evaluated. Due Date : 04/12/2023 Question 1 i.) Describe the concept of polling and interrupt-driven I/O mechanisms. What are the advantages and disadvantages of each approach in handling I/O operations? Provide real-world examples of where each might be more suitable. ii.) Explain the concept of buffering in I/O systems. How does buffering improve overall system performance, and what trade-offs are involved in selecting appropriate buffer sizes? iii.) Discuss the challenges of error handling in I/O systems. What strategies and mechanisms are used to detect and handle errors effectively in I/O operations? Question 2 iv.) Briefly explain the steps involved in handling a page fault by an operating system. v.) Memory paging is a feature that permits extending the address space far beyond the available memory. [X] and [Y] denote different addresses. Name the components given as [X], [Y] and [Z] in the following diagram (Figure 2.1) and describe how the extension of the address space happens. Figure 2.1: Memory Paging 1 vi.) The following diagram (Figure 2.2) depicts CPU utilization vs degree of multiprogramming. Focus on the regions shown by (A) and (B) and describe the reasons for such a behavior. Figure 2.2: CPU Utilization vs Degree of multiprogramming Question 3 i.) Discuss the concept of virtualization in modern operating systems. How does virtualization benefit system management and resource allocation, and what are the different types of virtualization techniques employed in contemporary operating systems? ii.) Explain the role of multi-core processors and parallel processing in operating systems. How do modern operating systems harness the power of multiple cores, and what challenges arise in terms of synchronization and resource sharing? iii.) Describe the concept of secure boot in operating systems. What is the significance of secure boot, and how does it protect the integrity of the OS during the boot process? Discuss the role of Trusted Platform Module (TPM) in secure boot. Question 4 iv.) Using two operating systems you are familiar with as examples, describe how the types of files in the file systems are similar or differ. v.) Shared files and directories in a file system can be implemented in several ways. Name two common approaches adopted by operating systems for this and discuss merits and demerits of each approach. vi.) Consider a file system that uses a modified contiguous allocation scheme with support for extents. A file is a collection of extents, with each extent corresponding to a contiguous set of blocks. A key issue in such systems is the degree of variability in the size of extents. State the advantages and disadvantages of the following schemes. a. All extents are the same size, and the size is predetermines. b. Extents can be of any size and are allocated dynamically. c. Extents can be of a few fixed sizes, and these sizes are predetermined. 2
