Operating Systems (AL-501) - Important Questions

What is an operating system? Explain its different types/classification with suitable examples.

Explain the services and functions provided by an operating system, including how they are provided through system calls and commands with examples.

Discuss disk space allocation methods: contiguous, linked and indexed allocation with diagrams, advantages and disadvantages.

Explain directory structures in file systems and discuss file protection mechanisms and access control methods.

Consider a given set of processes with arrival time and burst time. Draw Gantt chart and calculate turnaround time and waiting time for FCFS, SJF, SRTF and Round Robin (quantum 10) scheduling algorithms.

What are threads and multithreading? Compare user-level threads and kernel-level threads in terms of creation, scheduling, performance and overhead.

Explain the producer-consumer problem and its solution using semaphores, showing how synchronization and mutual exclusion are achieved.

What do you understand by system call? List and explain four system calls used for process management.

Define deadlock and explain the four necessary conditions / characterization for deadlock to occur.

Explain the Banker's algorithm for deadlock avoidance, including deadlock conditions.

Using Banker's algorithm on a given snapshot, compute the Need matrix, determine if the system is in a safe state with safe sequence, and check if a request can be granted.

Explain the concept of paging and how it helps in memory management.

Given memory partitions 100K, 500K, 200K, 300K, 600K in order, show how First-fit, Best-fit and Worst-fit place processes 212K, 417K, 112K and 426K in order and determine which algorithm makes the most effective use of memory.

Explain demand paging and determine the number of page faults for a given reference string using FIFO, LRU and Optimal page replacement algorithms with three page frames.

Explain the role of the Kernel I/O Subsystem in an operating system. Discuss how I/O requests are transformed into hardware operations.

Differentiate between synchronous and asynchronous I/O operations.