What are the three main purposes of an operating system?

Compare Monolithic, Layered, Microkernel, and Modular operating system structures. How does each structure organize components, and what are the main advantages and disadvantages? Provide examples.

Explain the key differences between Batch Operating Systems, Multiprogramming Operating Systems, and Multitasking (Time-Sharing) Operating Systems. Specifically, describe how each system manages processes, CPU utilization, and user interaction. Provide examples of scenarios or use cases where each type of operating system would be most effective

What is a process in an operating system, and how does it differ from a program? Explain the different states a process can be in during its lifecycle.

Explain the concept of process synchronization. Why is it necessary, and what problems can arise if processes are not properly synchronized?

Outline the lifecycle of a process, describing each state and the events that trigger transitions between these states.

Describe process scheduling and the role of the scheduler in managing processes. How do different scheduling algorithms (e.g., FCFS, Round Robin) affect process performance and CPU utilization?

What is inter-process communication (IPC), and what are some common IPC mechanisms (e.g., pipes, message queues, shared memory)? In which scenarios would each mechanism be most appropriate

What is process synchronization, and why is it important in an operating system? Describe common synchronization mechanisms (e.g., mutexes, semaphores) and explain how they prevent issues like race conditions.

Consider the following set of processes with their respective arrival times and burst times:

Use the Round Robin (RR) scheduling algorithm with a time quantum of 3 units to answer the following questions:

• For Round Robin (RR): Calculate the waiting time, turnaround time, and completion time for each process.
• How does the time quantum affect the waiting time and turnaround time compared to other scheduling algorithms such as FCFS or SJF?
• Compare the performance of RR with a time quantum of 3 units to a time quantum of 2 unit. Which setting provides better system performance and why?

Explain the difference between user-level threads and kernel-level threads. What are the advantages and disadvantages of each type of thread? Explain with example.

Consider a system with two types of resources (R1, R2) and three processes (P1, P2, P3). The following allocation and request details are given:

Draw the Resource Allocation Graph and determine if the system is in a deadlock state.

Describe the difference between deadlock prevention, deadlock avoidance, and deadlock detection. Provide examples of techniques used for each approach.

Explain the difference between internal and external fragmentation.

Define TLB with diagram. Given the following information about a system with a TLB: Total memory accesses = 1500, Number of TLB hits 1200, Number of TLB misses = 250 Calculate the TLB Hit Rate and TLB Miss Rate.

What is paging in an operating system, and how does it manage memory? Explain the role of page tables in mapping logical addresses to physical addresses.

Given memory partition of 100KB, 500KB, 200KB, 300K and 600KB (in order), how would each of the first fit, best fit and worst fit algorithms place processes of 212KB, 417KB,112KB and 426KB (in order)? Which algorithm makes the most efficient use of memory?

Consider the following page reference string:

7, 0, 1, 2, 0, 3, 0, 4, 2, 3, 0, 3, 0, 3, 2, 1

How many page faults would occur for the following replacement algorithms, assuming three frames? Remember that all frames are initially empty, so your first unique pages will cost one fault each.

i) MRU (Most Recently Used)
ii) Optimal Page Replacement
iii) Second-Chance (Clock) Page Replacement

Explain the differences between segmentation and paging in the context of virtual memory management. How do these techniques complement each other?

Briefly explain the purposes of system calls and system programs.

Explain the moving-head disk mechanism in operating systems. How does the read/write head of a disk move to access different tracks, and how does this mechanism affect disk performance? Discuss the factors that influence seek time and the different types of disk scheduling algorithms used to optimize disk head movement. Include necessary diagrams.

How do you calculate the disk access time? A disk is advertised with a seek time of 3ms, 512 bytes per sector and 128 sectors per track. The disk rotates at 5, 200 rpm.

• Determine the average rotational delay for the disk.
• Determine the time required to read a 4 Mbyte file. You are to assume that the file occupies sectors on adjacent tracks.

A hard disk with 4 platters that has 2048 tracks for each platter and 1024 sectors for each track and 512-byte sector. Calculate total capacity.