Operating Systems (CY-404) - Important Questions

Explain the services provided by an operating system to users and applications.

Discuss the characteristics and features of the operating system.

Explain the evolution of operating systems in detail and its impact on computing.

Define what a thread is and compare user-level vs kernel-level threads, including differences, advantages and disadvantages.

Explain how semaphores solve the critical section problem, including definition, wait/signal operations and illustrative example.

Define deadlock and explain the necessary conditions for deadlock and methods for deadlock prevention.

Consider three processes P1, P2, P3 with burst times 7, 3 and 6 units and arrival times 0, 1 and 2. Draw the Gantt chart and calculate average waiting time and average turnaround/completion time using Shortest Job First scheduling.

Consider the reference string 7, 0, 1, 2, 0, 3, 0, 4, 2, 3, 0, 3, 2, 1, 2, 0, 1, 7, 0, 1. Calculate the number of page faults using FIFO and LRU page replacement with 3 frames.

Define virtual memory and explain the advantages / benefits of virtual memory technique.

Explain the concept and need of demand paging with diagram.

Discuss contiguous file allocation method, including its advantages and disadvantages in comparison to linked allocation.

Calculate total head movement for FCFS disk scheduling given current head at track 143, previous at 125, and queue 86, 147, 91, 177, 94, 150, 102, 175, 130 on 0-199 tracks.

Write detailed notes on SSTF, SCAN and C-SCAN disk scheduling algorithms.

Explain the logical structure of I/O function with an example.

Differentiate between distributed and multiprocessor operating systems.