1. For the processes listed in the following table, draw a Gantt chart illustrating their execution using:

   • a) First-Come-First-Serve (FCFS)
   • b) Shortest-Job-First (SJF)
   • c) Shortest-Remaining-Time-Next (SRTN)
   • d) Round-Robin (quantum = 2)
   • e) Round-Robin (quantum = 1)

   Processes	Arrival Time	CPU Time
   A	0.000	3
   B	1.001	6
   C	4.001	4
   D	6.002	2

   • What is the turnaround time for each algorithm?

   OR

   What do you mean by disk management? What is the major difference between error handling and formatting?

2. How many page faults occur for each of the following page replacement algorithms for the reference string
   
   Code

   Copy

   0 1 7 2 3 2 7 1 0 3

   with four page frames and eight pages?
   Suppose all frames are initially empty.
   • a) Optimal replacement
   • b) FIFO replacement
   • c) LRU replacement
   • d) Clock replacement

3. Suppose that the disk drive has 50 cylinders, numbered from 0 to 49.
   The drive is currently serving the request at cylinder 20 and the previous request was at cylinder 25.
   The queue of pending requests is:
   Code

   Copy

   10, 22, 20, 2, 40, 6, 38

   (in this order).
   A seek takes 6 msec per cylinder moved. How much seek time is needed for the following disk-scheduling algorithms?
   • a) First-Come, First-Served (FCFS)
   • b) Shortest Seek Time First (SSTF)
   • c) SCAN
   • d) LOOK

Define the essential properties of the following types of operating systems:

• a) Batch
• b) Interactive
• c) Time sharing
• d) Real time
• e) Handheld

Describe how multithreading improves performance over a single-threaded solution.

“Using Semaphore is very critical for programmer.”
Do you support this statement? If yes, prove the statement with some logical facts.
If not, present your view with logical facts against the statement.

Students working at individual PCs in a computer laboratory send their files to be printed by a server which spools the files on its hard disk.
Under what conditions may a deadlock occur if the disk space for print spool is limited?
How may the deadlock be avoided?

What are Segmentation and Paging? Why are they sometimes combined into one scheme?

What are the differences between a trap and an interrupt? What is the use of each?

What is “device independence”? Define.

Explain how the File Allocation Table (FAT) manages files.
Mention the merits and demerits of using FAT.

Write short notes on (any two):
a) Unix file system
b) Race condition
c) Windows file system